- java.lang.Object
-
- java.nio.file.Files
-
public final class Files extends Object
This class consists exclusively of static methods that operate on files, directories, or other types of files.In most cases, the methods defined here will delegate to the associated file system provider to perform the file operations.
- Since:
- 1.7
-
-
Method Summary
Methods Modifier and Type Method and Description static long
copy(InputStream in, Path target, CopyOption... options)
Copies all bytes from an input stream to a file.static long
copy(Path source, OutputStream out)
Copies all bytes from a file to an output stream.static Path
copy(Path source, Path target, CopyOption... options)
Copy a file to a target file.static Path
createDirectories(Path dir, FileAttribute<?>... attrs)
Creates a directory by creating all nonexistent parent directories first.static Path
createDirectory(Path dir, FileAttribute<?>... attrs)
Creates a new directory.static Path
createFile(Path path, FileAttribute<?>... attrs)
Creates a new and empty file, failing if the file already exists.static Path
createLink(Path link, Path existing)
Creates a new link (directory entry) for an existing file (optional operation).static Path
createSymbolicLink(Path link, Path target, FileAttribute<?>... attrs)
Creates a symbolic link to a target (optional operation).static Path
createTempDirectory(Path dir, String prefix, FileAttribute<?>... attrs)
Creates a new directory in the specified directory, using the given prefix to generate its name.static Path
createTempDirectory(String prefix, FileAttribute<?>... attrs)
Creates a new directory in the default temporary-file directory, using the given prefix to generate its name.static Path
createTempFile(Path dir, String prefix, String suffix, FileAttribute<?>... attrs)
Creates a new empty file in the specified directory, using the given prefix and suffix strings to generate its name.static Path
createTempFile(String prefix, String suffix, FileAttribute<?>... attrs)
Creates an empty file in the default temporary-file directory, using the given prefix and suffix to generate its name.static void
delete(Path path)
Deletes a file.static boolean
deleteIfExists(Path path)
Deletes a file if it exists.static boolean
exists(Path path, LinkOption... options)
Tests whether a file exists.static Object
getAttribute(Path path, String attribute, LinkOption... options)
Reads the value of a file attribute.static <V extends FileAttributeView>
VgetFileAttributeView(Path path, Class<V> type, LinkOption... options)
Returns a file attribute view of a given type.static FileStore
getFileStore(Path path)
Returns theFileStore
representing the file store where a file is located.static FileTime
getLastModifiedTime(Path path, LinkOption... options)
Returns a file's last modified time.static UserPrincipal
getOwner(Path path, LinkOption... options)
Returns the owner of a file.static Set<PosixFilePermission>
getPosixFilePermissions(Path path, LinkOption... options)
Returns a file's POSIX file permissions.static boolean
isDirectory(Path path, LinkOption... options)
Tests whether a file is a directory.static boolean
isExecutable(Path path)
Tests whether a file is executable.static boolean
isHidden(Path path)
Tells whether or not a file is considered hidden.static boolean
isReadable(Path path)
Tests whether a file is readable.static boolean
isRegularFile(Path path, LinkOption... options)
Tests whether a file is a regular file with opaque content.static boolean
isSameFile(Path path, Path path2)
Tests if two paths locate the same file.static boolean
isSymbolicLink(Path path)
Tests whether a file is a symbolic link.static boolean
isWritable(Path path)
Tests whether a file is writable.static Path
move(Path source, Path target, CopyOption... options)
Move or rename a file to a target file.static BufferedReader
newBufferedReader(Path path, Charset cs)
Opens a file for reading, returning aBufferedReader
that may be used to read text from the file in an efficient manner.static BufferedWriter
newBufferedWriter(Path path, Charset cs, OpenOption... options)
Opens or creates a file for writing, returning aBufferedWriter
that may be used to write text to the file in an efficient manner.static SeekableByteChannel
newByteChannel(Path path, OpenOption... options)
Opens or creates a file, returning a seekable byte channel to access the file.static SeekableByteChannel
newByteChannel(Path path, Set<? extends OpenOption> options, FileAttribute<?>... attrs)
Opens or creates a file, returning a seekable byte channel to access the file.static DirectoryStream<Path>
newDirectoryStream(Path dir)
Opens a directory, returning aDirectoryStream
to iterate over all entries in the directory.static DirectoryStream<Path>
newDirectoryStream(Path dir, DirectoryStream.Filter<? super Path> filter)
Opens a directory, returning aDirectoryStream
to iterate over the entries in the directory.static DirectoryStream<Path>
newDirectoryStream(Path dir, String glob)
Opens a directory, returning aDirectoryStream
to iterate over the entries in the directory.static InputStream
newInputStream(Path path, OpenOption... options)
Opens a file, returning an input stream to read from the file.static OutputStream
newOutputStream(Path path, OpenOption... options)
Opens or creates a file, returning an output stream that may be used to write bytes to the file.static boolean
notExists(Path path, LinkOption... options)
Tests whether the file located by this path does not exist.static String
probeContentType(Path path)
Probes the content type of a file.static byte[]
readAllBytes(Path path)
Reads all the bytes from a file.static List<String>
readAllLines(Path path, Charset cs)
Read all lines from a file.static <A extends BasicFileAttributes>
AreadAttributes(Path path, Class<A> type, LinkOption... options)
Reads a file's attributes as a bulk operation.static Map<String,Object>
readAttributes(Path path, String attributes, LinkOption... options)
Reads a set of file attributes as a bulk operation.static Path
readSymbolicLink(Path link)
Reads the target of a symbolic link (optional operation).static Path
setAttribute(Path path, String attribute, Object value, LinkOption... options)
Sets the value of a file attribute.static Path
setLastModifiedTime(Path path, FileTime time)
Updates a file's last modified time attribute.static Path
setOwner(Path path, UserPrincipal owner)
Updates the file owner.static Path
setPosixFilePermissions(Path path, Set<PosixFilePermission> perms)
Sets a file's POSIX permissions.static long
size(Path path)
Returns the size of a file (in bytes).static Path
walkFileTree(Path start, FileVisitor<? super Path> visitor)
Walks a file tree.static Path
walkFileTree(Path start, Set<FileVisitOption> options, int maxDepth, FileVisitor<? super Path> visitor)
Walks a file tree.static Path
write(Path path, byte[] bytes, OpenOption... options)
Writes bytes to a file.static Path
write(Path path, Iterable<? extends CharSequence> lines, Charset cs, OpenOption... options)
Write lines of text to a file.
-
-
-
Method Detail
-
newInputStream
public static InputStream newInputStream(Path path, OpenOption... options) throws IOException
Opens a file, returning an input stream to read from the file. The stream will not be buffered, and is not required to support themark
orreset
methods. The stream will be safe for access by multiple concurrent threads. Reading commences at the beginning of the file. Whether the returned stream is asynchronously closeable and/or interruptible is highly file system provider specific and therefore not specified.The
options
parameter determines how the file is opened. If no options are present then it is equivalent to opening the file with theREAD
option. In addition to theREAD
option, an implementation may also support additional implementation specific options.- Parameters:
path
- the path to the file to openoptions
- options specifying how the file is opened- Returns:
- a new input stream
- Throws:
IllegalArgumentException
- if an invalid combination of options is specifiedUnsupportedOperationException
- if an unsupported option is specifiedIOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.
-
newOutputStream
public static OutputStream newOutputStream(Path path, OpenOption... options) throws IOException
Opens or creates a file, returning an output stream that may be used to write bytes to the file. The resulting stream will not be buffered. The stream will be safe for access by multiple concurrent threads. Whether the returned stream is asynchronously closeable and/or interruptible is highly file system provider specific and therefore not specified.This method opens or creates a file in exactly the manner specified by the
newByteChannel
method with the exception that theREAD
option may not be present in the array of options. If no options are present then this method works as if theCREATE
,TRUNCATE_EXISTING
, andWRITE
options are present. In other words, it opens the file for writing, creating the file if it doesn't exist, or initially truncating an existingregular-file
to a size of0
if it exists.Usage Examples:
Path path = ... // truncate and overwrite an existing file, or create the file if // it doesn't initially exist OutputStream out = Files.newOutputStream(path); // append to an existing file, fail if the file does not exist out = Files.newOutputStream(path, APPEND); // append to an existing file, create file if it doesn't initially exist out = Files.newOutputStream(path, CREATE, APPEND); // always create new file, failing if it already exists out = Files.newOutputStream(path, CREATE_NEW);
- Parameters:
path
- the path to the file to open or createoptions
- options specifying how the file is opened- Returns:
- a new output stream
- Throws:
IllegalArgumentException
- ifoptions
contains an invalid combination of optionsUnsupportedOperationException
- if an unsupported option is specifiedIOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the file. ThecheckDelete
method is invoked to check delete access if the file is opened with theDELETE_ON_CLOSE
option.
-
newByteChannel
public static SeekableByteChannel newByteChannel(Path path, Set<? extends OpenOption> options, FileAttribute<?>... attrs) throws IOException
Opens or creates a file, returning a seekable byte channel to access the file.The
options
parameter determines how the file is opened. TheREAD
andWRITE
options determine if the file should be opened for reading and/or writing. If neither option (or theAPPEND
option) is present then the file is opened for reading. By default reading or writing commence at the beginning of the file.In the addition to
READ
andWRITE
, the following options may be present:Option Description APPEND
If this option is present then the file is opened for writing and each invocation of the channel's write
method first advances the position to the end of the file and then writes the requested data. Whether the advancement of the position and the writing of the data are done in a single atomic operation is system-dependent and therefore unspecified. This option may not be used in conjunction with theREAD
orTRUNCATE_EXISTING
options.TRUNCATE_EXISTING
If this option is present then the existing file is truncated to a size of 0 bytes. This option is ignored when the file is opened only for reading. CREATE_NEW
If this option is present then a new file is created, failing if the file already exists or is a symbolic link. When creating a file the check for the existence of the file and the creation of the file if it does not exist is atomic with respect to other file system operations. This option is ignored when the file is opened only for reading. CREATE
If this option is present then an existing file is opened if it exists, otherwise a new file is created. This option is ignored if the CREATE_NEW
option is also present or the file is opened only for reading.DELETE_ON_CLOSE
When this option is present then the implementation makes a best effort attempt to delete the file when closed by the close
method. If theclose
method is not invoked then a best effort attempt is made to delete the file when the Java virtual machine terminates.SPARSE
When creating a new file this option is a hint that the new file will be sparse. This option is ignored when not creating a new file. SYNC
Requires that every update to the file's content or metadata be written synchronously to the underlying storage device. (see Synchronized I/O file integrity). DSYNC
Requires that every update to the file's content be written synchronously to the underlying storage device. (see Synchronized I/O file integrity). An implementation may also support additional implementation specific options.
The
attrs
parameter is optionalfile-attributes
to set atomically when a new file is created.In the case of the default provider, the returned seekable byte channel is a
FileChannel
.Usage Examples:
Path path = ... // open file for reading ReadableByteChannel rbc = Files.newByteChannel(path, EnumSet.of(READ))); // open file for writing to the end of an existing file, creating // the file if it doesn't already exist WritableByteChannel wbc = Files.newByteChannel(path, EnumSet.of(CREATE,APPEND)); // create file with initial permissions, opening it for both reading and writing
FileAttribute<<SetPosixFilePermission>> perms = ...
SeekableByteChannel sbc = Files.newByteChannel(path, EnumSet.of(CREATE_NEW,READ,WRITE), perms);- Parameters:
path
- the path to the file to open or createoptions
- options specifying how the file is openedattrs
- an optional list of file attributes to set atomically when creating the file- Returns:
- a new seekable byte channel
- Throws:
IllegalArgumentException
- if the set contains an invalid combination of optionsUnsupportedOperationException
- if an unsupported open option is specified or the array contains attributes that cannot be set atomically when creating the fileFileAlreadyExistsException
- if a file of that name already exists and theCREATE_NEW
option is specified (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the path if the file is opened for reading. ThecheckWrite
method is invoked to check write access to the path if the file is opened for writing. ThecheckDelete
method is invoked to check delete access if the file is opened with theDELETE_ON_CLOSE
option.- See Also:
FileChannel.open(Path,Set,FileAttribute[])
-
newByteChannel
public static SeekableByteChannel newByteChannel(Path path, OpenOption... options) throws IOException
Opens or creates a file, returning a seekable byte channel to access the file.This method opens or creates a file in exactly the manner specified by the
newByteChannel
method.- Parameters:
path
- the path to the file to open or createoptions
- options specifying how the file is opened- Returns:
- a new seekable byte channel
- Throws:
IllegalArgumentException
- if the set contains an invalid combination of optionsUnsupportedOperationException
- if an unsupported open option is specifiedFileAlreadyExistsException
- if a file of that name already exists and theCREATE_NEW
option is specified (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the path if the file is opened for reading. ThecheckWrite
method is invoked to check write access to the path if the file is opened for writing. ThecheckDelete
method is invoked to check delete access if the file is opened with theDELETE_ON_CLOSE
option.- See Also:
FileChannel.open(Path,OpenOption[])
-
newDirectoryStream
public static DirectoryStream<Path> newDirectoryStream(Path dir) throws IOException
Opens a directory, returning aDirectoryStream
to iterate over all entries in the directory. The elements returned by the directory stream'siterator
are of typePath
, each one representing an entry in the directory. ThePath
objects are obtained as if byresolving
the name of the directory entry againstdir
.When not using the try-with-resources construct, then directory stream's
close
method should be invoked after iteration is completed so as to free any resources held for the open directory.When an implementation supports operations on entries in the directory that execute in a race-free manner then the returned directory stream is a
SecureDirectoryStream
.- Parameters:
dir
- the path to the directory- Returns:
- a new and open
DirectoryStream
object - Throws:
NotDirectoryException
- if the file could not otherwise be opened because it is not a directory (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the directory.
-
newDirectoryStream
public static DirectoryStream<Path> newDirectoryStream(Path dir, String glob) throws IOException
Opens a directory, returning aDirectoryStream
to iterate over the entries in the directory. The elements returned by the directory stream'siterator
are of typePath
, each one representing an entry in the directory. ThePath
objects are obtained as if byresolving
the name of the directory entry againstdir
. The entries returned by the iterator are filtered by matching theString
representation of their file names against the given globbing pattern.For example, suppose we want to iterate over the files ending with ".java" in a directory:
Path dir = ... try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir, "*.java")) { : }
The globbing pattern is specified by the
getPathMatcher
method.When not using the try-with-resources construct, then directory stream's
close
method should be invoked after iteration is completed so as to free any resources held for the open directory.When an implementation supports operations on entries in the directory that execute in a race-free manner then the returned directory stream is a
SecureDirectoryStream
.- Parameters:
dir
- the path to the directoryglob
- the glob pattern- Returns:
- a new and open
DirectoryStream
object - Throws:
PatternSyntaxException
- if the pattern is invalidNotDirectoryException
- if the file could not otherwise be opened because it is not a directory (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the directory.
-
newDirectoryStream
public static DirectoryStream<Path> newDirectoryStream(Path dir, DirectoryStream.Filter<? super Path> filter) throws IOException
Opens a directory, returning aDirectoryStream
to iterate over the entries in the directory. The elements returned by the directory stream'siterator
are of typePath
, each one representing an entry in the directory. ThePath
objects are obtained as if byresolving
the name of the directory entry againstdir
. The entries returned by the iterator are filtered by the givenfilter
.When not using the try-with-resources construct, then directory stream's
close
method should be invoked after iteration is completed so as to free any resources held for the open directory.Where the filter terminates due to an uncaught error or runtime exception then it is propagated to the
hasNext
ornext
method. Where anIOException
is thrown, it results in thehasNext
ornext
method throwing aDirectoryIteratorException
with theIOException
as the cause.When an implementation supports operations on entries in the directory that execute in a race-free manner then the returned directory stream is a
SecureDirectoryStream
.Usage Example: Suppose we want to iterate over the files in a directory that are larger than 8K.
DirectoryStream.Filter<Path> filter = new DirectoryStream.Filter<Path>() { public boolean accept(Path file) throws IOException { return (Files.size(file) > 8192L); } }; Path dir = ... try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir, filter)) { : }
- Parameters:
dir
- the path to the directoryfilter
- the directory stream filter- Returns:
- a new and open
DirectoryStream
object - Throws:
NotDirectoryException
- if the file could not otherwise be opened because it is not a directory (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the directory.
-
createFile
public static Path createFile(Path path, FileAttribute<?>... attrs) throws IOException
Creates a new and empty file, failing if the file already exists. The check for the existence of the file and the creation of the new file if it does not exist are a single operation that is atomic with respect to all other filesystem activities that might affect the directory.The
attrs
parameter is optionalfile-attributes
to set atomically when creating the file. Each attribute is identified by itsname
. If more than one attribute of the same name is included in the array then all but the last occurrence is ignored.- Parameters:
path
- the path to the file to createattrs
- an optional list of file attributes to set atomically when creating the file- Returns:
- the file
- Throws:
UnsupportedOperationException
- if the array contains an attribute that cannot be set atomically when creating the fileFileAlreadyExistsException
- if a file of that name already exists (optional specific exception)IOException
- if an I/O error occurs or the parent directory does not existSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the new file.
-
createDirectory
public static Path createDirectory(Path dir, FileAttribute<?>... attrs) throws IOException
Creates a new directory. The check for the existence of the file and the creation of the directory if it does not exist are a single operation that is atomic with respect to all other filesystem activities that might affect the directory. ThecreateDirectories
method should be used where it is required to create all nonexistent parent directories first.The
attrs
parameter is optionalfile-attributes
to set atomically when creating the directory. Each attribute is identified by itsname
. If more than one attribute of the same name is included in the array then all but the last occurrence is ignored.- Parameters:
dir
- the directory to createattrs
- an optional list of file attributes to set atomically when creating the directory- Returns:
- the directory
- Throws:
UnsupportedOperationException
- if the array contains an attribute that cannot be set atomically when creating the directoryFileAlreadyExistsException
- if a directory could not otherwise be created because a file of that name already exists (optional specific exception)IOException
- if an I/O error occurs or the parent directory does not existSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the new directory.
-
createDirectories
public static Path createDirectories(Path dir, FileAttribute<?>... attrs) throws IOException
Creates a directory by creating all nonexistent parent directories first. Unlike thecreateDirectory
method, an exception is not thrown if the directory could not be created because it already exists.The
attrs
parameter is optionalfile-attributes
to set atomically when creating the nonexistent directories. Each file attribute is identified by itsname
. If more than one attribute of the same name is included in the array then all but the last occurrence is ignored.If this method fails, then it may do so after creating some, but not all, of the parent directories.
- Parameters:
dir
- the directory to createattrs
- an optional list of file attributes to set atomically when creating the directory- Returns:
- the directory
- Throws:
UnsupportedOperationException
- if the array contains an attribute that cannot be set atomically when creating the directoryFileAlreadyExistsException
- ifdir
exists but is not a directory (optional specific exception)IOException
- if an I/O error occursSecurityException
- in the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked prior to attempting to create a directory and itscheckRead
is invoked for each parent directory that is checked. Ifdir
is not an absolute path then itstoAbsolutePath
may need to be invoked to get its absolute path. This may invoke the security manager'scheckPropertyAccess
method to check access to the system propertyuser.dir
-
createTempFile
public static Path createTempFile(Path dir, String prefix, String suffix, FileAttribute<?>... attrs) throws IOException
Creates a new empty file in the specified directory, using the given prefix and suffix strings to generate its name. The resultingPath
is associated with the sameFileSystem
as the given directory.The details as to how the name of the file is constructed is implementation dependent and therefore not specified. Where possible the
prefix
andsuffix
are used to construct candidate names in the same manner as theFile.createTempFile(String,String,File)
method.As with the
File.createTempFile
methods, this method is only part of a temporary-file facility. Where used as a work files, the resulting file may be opened using theDELETE_ON_CLOSE
option so that the file is deleted when the appropriateclose
method is invoked. Alternatively, ashutdown-hook
, or theFile.deleteOnExit()
mechanism may be used to delete the file automatically.The
attrs
parameter is optionalfile-attributes
to set atomically when creating the file. Each attribute is identified by itsname
. If more than one attribute of the same name is included in the array then all but the last occurrence is ignored. When no file attributes are specified, then the resulting file may have more restrictive access permissions to files created by theFile.createTempFile(String,String,File)
method.- Parameters:
dir
- the path to directory in which to create the fileprefix
- the prefix string to be used in generating the file's name; may benull
suffix
- the suffix string to be used in generating the file's name; may benull
, in which case ".tmp
" is usedattrs
- an optional list of file attributes to set atomically when creating the file- Returns:
- the path to the newly created file that did not exist before this method was invoked
- Throws:
IllegalArgumentException
- if the prefix or suffix parameters cannot be used to generate a candidate file nameUnsupportedOperationException
- if the array contains an attribute that cannot be set atomically when creating the directoryIOException
- if an I/O error occurs ordir
does not existSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the file.
-
createTempFile
public static Path createTempFile(String prefix, String suffix, FileAttribute<?>... attrs) throws IOException
Creates an empty file in the default temporary-file directory, using the given prefix and suffix to generate its name. The resultingPath
is associated with the defaultFileSystem
.This method works in exactly the manner specified by the
createTempFile(Path,String,String,FileAttribute[])
method for the case that thedir
parameter is the temporary-file directory.- Parameters:
prefix
- the prefix string to be used in generating the file's name; may benull
suffix
- the suffix string to be used in generating the file's name; may benull
, in which case ".tmp
" is usedattrs
- an optional list of file attributes to set atomically when creating the file- Returns:
- the path to the newly created file that did not exist before this method was invoked
- Throws:
IllegalArgumentException
- if the prefix or suffix parameters cannot be used to generate a candidate file nameUnsupportedOperationException
- if the array contains an attribute that cannot be set atomically when creating the directoryIOException
- if an I/O error occurs or the temporary-file directory does not existSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the file.
-
createTempDirectory
public static Path createTempDirectory(Path dir, String prefix, FileAttribute<?>... attrs) throws IOException
Creates a new directory in the specified directory, using the given prefix to generate its name. The resultingPath
is associated with the sameFileSystem
as the given directory.The details as to how the name of the directory is constructed is implementation dependent and therefore not specified. Where possible the
prefix
is used to construct candidate names.As with the
createTempFile
methods, this method is only part of a temporary-file facility. Ashutdown-hook
, or theFile.deleteOnExit()
mechanism may be used to delete the directory automatically.The
attrs
parameter is optionalfile-attributes
to set atomically when creating the directory. Each attribute is identified by itsname
. If more than one attribute of the same name is included in the array then all but the last occurrence is ignored.- Parameters:
dir
- the path to directory in which to create the directoryprefix
- the prefix string to be used in generating the directory's name; may benull
attrs
- an optional list of file attributes to set atomically when creating the directory- Returns:
- the path to the newly created directory that did not exist before this method was invoked
- Throws:
IllegalArgumentException
- if the prefix cannot be used to generate a candidate directory nameUnsupportedOperationException
- if the array contains an attribute that cannot be set atomically when creating the directoryIOException
- if an I/O error occurs ordir
does not existSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access when creating the directory.
-
createTempDirectory
public static Path createTempDirectory(String prefix, FileAttribute<?>... attrs) throws IOException
Creates a new directory in the default temporary-file directory, using the given prefix to generate its name. The resultingPath
is associated with the defaultFileSystem
.This method works in exactly the manner specified by
createTempDirectory(Path,String,FileAttribute[])
method for the case that thedir
parameter is the temporary-file directory.- Parameters:
prefix
- the prefix string to be used in generating the directory's name; may benull
attrs
- an optional list of file attributes to set atomically when creating the directory- Returns:
- the path to the newly created directory that did not exist before this method was invoked
- Throws:
IllegalArgumentException
- if the prefix cannot be used to generate a candidate directory nameUnsupportedOperationException
- if the array contains an attribute that cannot be set atomically when creating the directoryIOException
- if an I/O error occurs or the temporary-file directory does not existSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access when creating the directory.
-
createSymbolicLink
public static Path createSymbolicLink(Path link, Path target, FileAttribute<?>... attrs) throws IOException
Creates a symbolic link to a target (optional operation).The
target
parameter is the target of the link. It may be anabsolute
or relative path and may not exist. When the target is a relative path then file system operations on the resulting link are relative to the path of the link.The
attrs
parameter is optionalattributes
to set atomically when creating the link. Each attribute is identified by itsname
. If more than one attribute of the same name is included in the array then all but the last occurrence is ignored.Where symbolic links are supported, but the underlying
FileStore
does not support symbolic links, then this may fail with anIOException
. Additionally, some operating systems may require that the Java virtual machine be started with implementation specific privileges to create symbolic links, in which case this method may throwIOException
.- Parameters:
link
- the path of the symbolic link to createtarget
- the target of the symbolic linkattrs
- the array of attributes to set atomically when creating the symbolic link- Returns:
- the path to the symbolic link
- Throws:
UnsupportedOperationException
- if the implementation does not support symbolic links or the array contains an attribute that cannot be set atomically when creating the symbolic linkFileAlreadyExistsException
- if a file with the name already exists (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, it deniesLinkPermission
("symbolic") or itscheckWrite
method denies write access to the path of the symbolic link.
-
createLink
public static Path createLink(Path link, Path existing) throws IOException
Creates a new link (directory entry) for an existing file (optional operation).The
link
parameter locates the directory entry to create. Theexisting
parameter is the path to an existing file. This method creates a new directory entry for the file so that it can be accessed usinglink
as the path. On some file systems this is known as creating a "hard link". Whether the file attributes are maintained for the file or for each directory entry is file system specific and therefore not specified. Typically, a file system requires that all links (directory entries) for a file be on the same file system. Furthermore, on some platforms, the Java virtual machine may require to be started with implementation specific privileges to create hard links or to create links to directories.- Parameters:
link
- the link (directory entry) to createexisting
- a path to an existing file- Returns:
- the path to the link (directory entry)
- Throws:
UnsupportedOperationException
- if the implementation does not support adding an existing file to a directoryFileAlreadyExistsException
- if the entry could not otherwise be created because a file of that name already exists (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, it deniesLinkPermission
("hard") or itscheckWrite
method denies write access to either the link or the existing file.
-
delete
public static void delete(Path path) throws IOException
Deletes a file.An implementation may require to examine the file to determine if the file is a directory. Consequently this method may not be atomic with respect to other file system operations. If the file is a symbolic link then the symbolic link itself, not the final target of the link, is deleted.
If the file is a directory then the directory must be empty. In some implementations a directory has entries for special files or links that are created when the directory is created. In such implementations a directory is considered empty when only the special entries exist. This method can be used with the
walkFileTree
method to delete a directory and all entries in the directory, or an entire file-tree where required.On some operating systems it may not be possible to remove a file when it is open and in use by this Java virtual machine or other programs.
- Parameters:
path
- the path to the file to delete- Throws:
NoSuchFileException
- if the file does not exist (optional specific exception)DirectoryNotEmptyException
- if the file is a directory and could not otherwise be deleted because the directory is not empty (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, theSecurityManager.checkDelete(String)
method is invoked to check delete access to the file
-
deleteIfExists
public static boolean deleteIfExists(Path path) throws IOException
Deletes a file if it exists.As with the
delete(Path)
method, an implementation may need to examine the file to determine if the file is a directory. Consequently this method may not be atomic with respect to other file system operations. If the file is a symbolic link, then the symbolic link itself, not the final target of the link, is deleted.If the file is a directory then the directory must be empty. In some implementations a directory has entries for special files or links that are created when the directory is created. In such implementations a directory is considered empty when only the special entries exist.
On some operating systems it may not be possible to remove a file when it is open and in use by this Java virtual machine or other programs.
- Parameters:
path
- the path to the file to delete- Returns:
true
if the file was deleted by this method;false
if the file could not be deleted because it did not exist- Throws:
DirectoryNotEmptyException
- if the file is a directory and could not otherwise be deleted because the directory is not empty (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, theSecurityManager.checkDelete(String)
method is invoked to check delete access to the file.
-
copy
public static Path copy(Path source, Path target, CopyOption... options) throws IOException
Copy a file to a target file.This method copies a file to the target file with the
options
parameter specifying how the copy is performed. By default, the copy fails if the target file already exists or is a symbolic link, except if the source and target are thesame
file, in which case the method completes without copying the file. File attributes are not required to be copied to the target file. If symbolic links are supported, and the file is a symbolic link, then the final target of the link is copied. If the file is a directory then it creates an empty directory in the target location (entries in the directory are not copied). This method can be used with thewalkFileTree
method to copy a directory and all entries in the directory, or an entire file-tree where required.The
options
parameter may include any of the following:Option Description REPLACE_EXISTING
If the target file exists, then the target file is replaced if it is not a non-empty directory. If the target file exists and is a symbolic link, then the symbolic link itself, not the target of the link, is replaced. COPY_ATTRIBUTES
Attempts to copy the file attributes associated with this file to the target file. The exact file attributes that are copied is platform and file system dependent and therefore unspecified. Minimally, the last-modified-time
is copied to the target file if supported by both the source and target file store. Copying of file timestamps may result in precision loss.NOFOLLOW_LINKS
Symbolic links are not followed. If the file is a symbolic link, then the symbolic link itself, not the target of the link, is copied. It is implementation specific if file attributes can be copied to the new link. In other words, the COPY_ATTRIBUTES
option may be ignored when copying a symbolic link.An implementation of this interface may support additional implementation specific options.
Copying a file is not an atomic operation. If an
IOException
is thrown then it possible that the target file is incomplete or some of its file attributes have not been copied from the source file. When theREPLACE_EXISTING
option is specified and the target file exists, then the target file is replaced. The check for the existence of the file and the creation of the new file may not be atomic with respect to other file system activities.Usage Example: Suppose we want to copy a file into a directory, giving it the same file name as the source file:
Path source = ... Path newdir = ... Files.copy(source, newdir.resolve(source.getFileName());
- Parameters:
source
- the path to the file to copytarget
- the path to the target file (may be associated with a different provider to the source path)options
- options specifying how the copy should be done- Returns:
- the path to the target file
- Throws:
UnsupportedOperationException
- if the array contains a copy option that is not supportedFileAlreadyExistsException
- if the target file exists but cannot be replaced because theREPLACE_EXISTING
option is not specified (optional specific exception)DirectoryNotEmptyException
- theREPLACE_EXISTING
option is specified but the file cannot be replaced because it is a non-empty directory (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the source file, thecheckWrite
is invoked to check write access to the target file. If a symbolic link is copied the security manager is invoked to checkLinkPermission
("symbolic")
.
-
move
public static Path move(Path source, Path target, CopyOption... options) throws IOException
Move or rename a file to a target file.By default, this method attempts to move the file to the target file, failing if the target file exists except if the source and target are the
same
file, in which case this method has no effect. If the file is a symbolic link then the symbolic link itself, not the target of the link, is moved. This method may be invoked to move an empty directory. In some implementations a directory has entries for special files or links that are created when the directory is created. In such implementations a directory is considered empty when only the special entries exist. When invoked to move a directory that is not empty then the directory is moved if it does not require moving the entries in the directory. For example, renaming a directory on the sameFileStore
will usually not require moving the entries in the directory. When moving a directory requires that its entries be moved then this method fails (by throwing anIOException
). To move a file tree may involve copying rather than moving directories and this can be done using thecopy
method in conjunction with theFiles.walkFileTree
utility method.The
options
parameter may include any of the following:Option Description REPLACE_EXISTING
If the target file exists, then the target file is replaced if it is not a non-empty directory. If the target file exists and is a symbolic link, then the symbolic link itself, not the target of the link, is replaced. ATOMIC_MOVE
The move is performed as an atomic file system operation and all other options are ignored. If the target file exists then it is implementation specific if the existing file is replaced or this method fails by throwing an IOException
. If the move cannot be performed as an atomic file system operation thenAtomicMoveNotSupportedException
is thrown. This can arise, for example, when the target location is on a differentFileStore
and would require that the file be copied, or target location is associated with a different provider to this object.An implementation of this interface may support additional implementation specific options.
Where the move requires that the file be copied then the
last-modified-time
is copied to the new file. An implementation may also attempt to copy other file attributes but is not required to fail if the file attributes cannot be copied. When the move is performed as a non-atomic operation, and aIOException
is thrown, then the state of the files is not defined. The original file and the target file may both exist, the target file may be incomplete or some of its file attributes may not been copied from the original file.Usage Examples: Suppose we want to rename a file to "newname", keeping the file in the same directory:
Path source = ... Files.move(source, source.resolveSibling("newname"));
Alternatively, suppose we want to move a file to new directory, keeping the same file name, and replacing any existing file of that name in the directory:Path source = ... Path newdir = ... Files.move(source, newdir.resolve(source.getFileName()), REPLACE_EXISTING);
- Parameters:
source
- the path to the file to movetarget
- the path to the target file (may be associated with a different provider to the source path)options
- options specifying how the move should be done- Returns:
- the path to the target file
- Throws:
UnsupportedOperationException
- if the array contains a copy option that is not supportedFileAlreadyExistsException
- if the target file exists but cannot be replaced because theREPLACE_EXISTING
option is not specified (optional specific exception)DirectoryNotEmptyException
- theREPLACE_EXISTING
option is specified but the file cannot be replaced because it is a non-empty directory (optional specific exception)AtomicMoveNotSupportedException
- if the options array contains theATOMIC_MOVE
option but the file cannot be moved as an atomic file system operation.IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to both the source and target file.
-
readSymbolicLink
public static Path readSymbolicLink(Path link) throws IOException
Reads the target of a symbolic link (optional operation).If the file system supports symbolic links then this method is used to read the target of the link, failing if the file is not a symbolic link. The target of the link need not exist. The returned
Path
object will be associated with the same file system aslink
.- Parameters:
link
- the path to the symbolic link- Returns:
- a
Path
object representing the target of the link - Throws:
UnsupportedOperationException
- if the implementation does not support symbolic linksNotLinkException
- if the target could otherwise not be read because the file is not a symbolic link (optional specific exception)IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, it checks thatFilePermission
has been granted with the "readlink
" action to read the link.
-
getFileStore
public static FileStore getFileStore(Path path) throws IOException
Returns theFileStore
representing the file store where a file is located.Once a reference to the
FileStore
is obtained it is implementation specific if operations on the returnedFileStore
, orFileStoreAttributeView
objects obtained from it, continue to depend on the existence of the file. In particular the behavior is not defined for the case that the file is deleted or moved to a different file store.- Parameters:
path
- the path to the file- Returns:
- the file store where the file is stored
- Throws:
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file, and in addition it checksRuntimePermission
("getFileStoreAttributes")
-
isSameFile
public static boolean isSameFile(Path path, Path path2) throws IOException
Tests if two paths locate the same file.If both
Path
objects areequal
then this method returnstrue
without checking if the file exists. If the twoPath
objects are associated with different providers then this method returnsfalse
. Otherwise, this method checks if bothPath
objects locate the same file, and depending on the implementation, may require to open or access both files.If the file system and files remain static, then this method implements an equivalence relation for non-null
Paths
.- It is reflexive: for
Path
f
,isSameFile(f,f)
should returntrue
. - It is symmetric: for two
Paths
f
andg
,isSameFile(f,g)
will equalisSameFile(g,f)
. - It is transitive: for three
Paths
f
,g
, andh
, ifisSameFile(f,g)
returnstrue
andisSameFile(g,h)
returnstrue
, thenisSameFile(g,h)
will return returntrue
.
- Parameters:
path
- one path to the filepath2
- the other path- Returns:
true
if, and only if, the two paths locate the same file- Throws:
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to both files.- See Also:
BasicFileAttributes.fileKey()
- It is reflexive: for
-
isHidden
public static boolean isHidden(Path path) throws IOException
Tells whether or not a file is considered hidden. The exact definition of hidden is platform or provider dependent. On UNIX for example a file is considered to be hidden if its name begins with a period character ('.'). On Windows a file is considered hidden if it isn't a directory and the DOShidden
attribute is set.Depending on the implementation this method may require to access the file system to determine if the file is considered hidden.
- Parameters:
path
- the path to the file to test- Returns:
true
if the file is considered hidden- Throws:
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.
-
probeContentType
public static String probeContentType(Path path) throws IOException
Probes the content type of a file.This method uses the installed
FileTypeDetector
implementations to probe the given file to determine its content type. Each file type detector'sprobeContentType
is invoked, in turn, to probe the file type. If the file is recognized then the content type is returned. If the file is not recognized by any of the installed file type detectors then a system-default file type detector is invoked to guess the content type.A given invocation of the Java virtual machine maintains a system-wide list of file type detectors. Installed file type detectors are loaded using the service-provider loading facility defined by the
ServiceLoader
class. Installed file type detectors are loaded using the system class loader. If the system class loader cannot be found then the extension class loader is used; If the extension class loader cannot be found then the bootstrap class loader is used. File type detectors are typically installed by placing them in a JAR file on the application class path or in the extension directory, the JAR file contains a provider-configuration file namedjava.nio.file.spi.FileTypeDetector
in the resource directoryMETA-INF/services
, and the file lists one or more fully-qualified names of concrete subclass ofFileTypeDetector
that have a zero argument constructor. If the process of locating or instantiating the installed file type detectors fails then an unspecified error is thrown. The ordering that installed providers are located is implementation specific.The return value of this method is the string form of the value of a Multipurpose Internet Mail Extension (MIME) content type as defined by RFC 2045: Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies. The string is guaranteed to be parsable according to the grammar in the RFC.
- Parameters:
path
- the path to the file to probe- Returns:
- The content type of the file, or
null
if the content type cannot be determined - Throws:
IOException
- if an I/O error occursSecurityException
- If a security manager is installed and it denies an unspecified permission required by a file type detector implementation.
-
getFileAttributeView
public static <V extends FileAttributeView> V getFileAttributeView(Path path, Class<V> type, LinkOption... options)
Returns a file attribute view of a given type.A file attribute view provides a read-only or updatable view of a set of file attributes. This method is intended to be used where the file attribute view defines type-safe methods to read or update the file attributes. The
type
parameter is the type of the attribute view required and the method returns an instance of that type if supported. TheBasicFileAttributeView
type supports access to the basic attributes of a file. Invoking this method to select a file attribute view of that type will always return an instance of that class.The
options
array may be used to indicate how symbolic links are handled by the resulting file attribute view for the case that the file is a symbolic link. By default, symbolic links are followed. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed. This option is ignored by implementations that do not support symbolic links.Usage Example: Suppose we want read or set a file's ACL, if supported:
Path path = ... AclFileAttributeView view = Files.getFileAttributeView(path, AclFileAttributeView.class); if (view != null) { List<AclEntry> acl = view.getAcl(); : }
- Parameters:
path
- the path to the filetype
- theClass
object corresponding to the file attribute viewoptions
- options indicating how symbolic links are handled- Returns:
- a file attribute view of the specified type, or
null
if the attribute view type is not available
-
readAttributes
public static <A extends BasicFileAttributes> A readAttributes(Path path, Class<A> type, LinkOption... options) throws IOException
Reads a file's attributes as a bulk operation.The
type
parameter is the type of the attributes required and this method returns an instance of that type if supported. All implementations support a basic set of file attributes and so invoking this method with atype
parameter ofBasicFileAttributes.class
will not throwUnsupportedOperationException
.The
options
array may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed and the file attribute of the final target of the link is read. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.It is implementation specific if all file attributes are read as an atomic operation with respect to other file system operations.
Usage Example: Suppose we want to read a file's attributes in bulk:
Path path = ... BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class);
Alternatively, suppose we want to read file's POSIX attributes without following symbolic links:PosixFileAttributes attrs = Files.readAttributes(path, PosixFileAttributes.class, NOFOLLOW_LINKS);
- Parameters:
path
- the path to the filetype
- theClass
of the file attributes required to readoptions
- options indicating how symbolic links are handled- Returns:
- the file attributes
- Throws:
UnsupportedOperationException
- if an attributes of the given type are not supportedIOException
- if an I/O error occursSecurityException
- In the case of the default provider, a security manager is installed, itscheckRead
method is invoked to check read access to the file. If this method is invoked to read security sensitive attributes then the security manager may be invoke to check for additional permissions.
-
setAttribute
public static Path setAttribute(Path path, String attribute, Object value, LinkOption... options) throws IOException
Sets the value of a file attribute.The
attribute
parameter identifies the attribute to be set and takes the form:[view-name:]attribute-name
where square brackets [...] delineate an optional component and the character':'
stands for itself.view-name is the
name
of aFileAttributeView
that identifies a set of file attributes. If not specified then it defaults to"basic"
, the name of the file attribute view that identifies the basic set of file attributes common to many file systems. attribute-name is the name of the attribute within the set.The
options
array may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed and the file attribute of the final target of the link is set. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.Usage Example: Suppose we want to set the DOS "hidden" attribute:
Path path = ... Files.setAttribute(path, "dos:hidden", true);
- Parameters:
path
- the path to the fileattribute
- the attribute to setvalue
- the attribute valueoptions
- options indicating how symbolic links are handled- Returns:
- the
path
parameter - Throws:
UnsupportedOperationException
- if the attribute view is not availableIllegalArgumentException
- if the attribute name is not specified, or is not recognized, or the attribute value is of the correct type but has an inappropriate valueClassCastException
- if the attribute value is not of the expected type or is a collection containing elements that are not of the expected typeIOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, itscheckWrite
method denies write access to the file. If this method is invoked to set security sensitive attributes then the security manager may be invoked to check for additional permissions.
-
getAttribute
public static Object getAttribute(Path path, String attribute, LinkOption... options) throws IOException
Reads the value of a file attribute.The
attribute
parameter identifies the attribute to be read and takes the form:[view-name:]attribute-name
where square brackets [...] delineate an optional component and the character':'
stands for itself.view-name is the
name
of aFileAttributeView
that identifies a set of file attributes. If not specified then it defaults to"basic"
, the name of the file attribute view that identifies the basic set of file attributes common to many file systems. attribute-name is the name of the attribute.The
options
array may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed and the file attribute of the final target of the link is read. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.Usage Example: Suppose we require the user ID of the file owner on a system that supports a "
unix
" view:Path path = ... int uid = (Integer)Files.getAttribute(path, "unix:uid");
- Parameters:
path
- the path to the fileattribute
- the attribute to readoptions
- options indicating how symbolic links are handled- Returns:
- the attribute value
- Throws:
UnsupportedOperationException
- if the attribute view is not availableIllegalArgumentException
- if the attribute name is not specified or is not recognizedIOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, itscheckRead
method denies read access to the file. If this method is invoked to read security sensitive attributes then the security manager may be invoked to check for additional permissions.
-
readAttributes
public static Map<String,Object> readAttributes(Path path, String attributes, LinkOption... options) throws IOException
Reads a set of file attributes as a bulk operation.The
attributes
parameter identifies the attributes to be read and takes the form:[view-name:]attribute-list
where square brackets [...] delineate an optional component and the character':'
stands for itself.view-name is the
name
of aFileAttributeView
that identifies a set of file attributes. If not specified then it defaults to"basic"
, the name of the file attribute view that identifies the basic set of file attributes common to many file systems.The attribute-list component is a comma separated list of zero or more names of attributes to read. If the list contains the value
"*"
then all attributes are read. Attributes that are not supported are ignored and will not be present in the returned map. It is implementation specific if all attributes are read as an atomic operation with respect to other file system operations.The following examples demonstrate possible values for the
attributes
parameter:"*"
Read all basic-file-attributes
."size,lastModifiedTime,lastAccessTime"
Reads the file size, last modified time, and last access time attributes. "posix:*"
Read all POSIX-file-attributes
."posix:permissions,owner,size"
Reads the POSX file permissions, owner, and file size. The
options
array may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed and the file attribute of the final target of the link is read. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.- Parameters:
path
- the path to the fileattributes
- the attributes to readoptions
- options indicating how symbolic links are handled- Returns:
- a map of the attributes returned; The map's keys are the attribute names, its values are the attribute values
- Throws:
UnsupportedOperationException
- if the attribute view is not availableIllegalArgumentException
- if no attributes are specified or an unrecognized attributes is specifiedIOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, itscheckRead
method denies read access to the file. If this method is invoked to read security sensitive attributes then the security manager may be invoke to check for additional permissions.
-
getPosixFilePermissions
public static Set<PosixFilePermission> getPosixFilePermissions(Path path, LinkOption... options) throws IOException
Returns a file's POSIX file permissions.The
path
parameter is associated with aFileSystem
that supports thePosixFileAttributeView
. This attribute view provides access to file attributes commonly associated with files on file systems used by operating systems that implement the Portable Operating System Interface (POSIX) family of standards.The
options
array may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed and the file attribute of the final target of the link is read. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.- Parameters:
path
- the path to the fileoptions
- options indicating how symbolic links are handled- Returns:
- the file permissions
- Throws:
UnsupportedOperationException
- if the associated file system does not support thePosixFileAttributeView
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, a security manager is installed, and it deniesRuntimePermission
("accessUserInformation") or itscheckRead
method denies read access to the file.
-
setPosixFilePermissions
public static Path setPosixFilePermissions(Path path, Set<PosixFilePermission> perms) throws IOException
Sets a file's POSIX permissions.The
path
parameter is associated with aFileSystem
that supports thePosixFileAttributeView
. This attribute view provides access to file attributes commonly associated with files on file systems used by operating systems that implement the Portable Operating System Interface (POSIX) family of standards.- Parameters:
path
- A file reference that locates the fileperms
- The new set of permissions- Throws:
UnsupportedOperationException
- if the associated file system does not support thePosixFileAttributeView
ClassCastException
- if the sets contains elements that are not of typePosixFilePermission
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, it deniesRuntimePermission
("accessUserInformation") or itscheckWrite
method denies write access to the file.
-
getOwner
public static UserPrincipal getOwner(Path path, LinkOption... options) throws IOException
Returns the owner of a file.The
path
parameter is associated with a file system that supportsFileOwnerAttributeView
. This file attribute view provides access to a file attribute that is the owner of the file.- Parameters:
path
- A file reference that locates the fileoptions
- options indicating how symbolic links are handled- Returns:
- A user principal representing the owner of the file
- Throws:
UnsupportedOperationException
- if the associated file system does not support theFileOwnerAttributeView
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, it deniesRuntimePermission
("accessUserInformation") or itscheckRead
method denies read access to the file.
-
setOwner
public static Path setOwner(Path path, UserPrincipal owner) throws IOException
Updates the file owner.The
path
parameter is associated with a file system that supportsFileOwnerAttributeView
. This file attribute view provides access to a file attribute that is the owner of the file.Usage Example: Suppose we want to make "joe" the owner of a file:
Path path = ... UserPrincipalLookupService lookupService = provider(path).getUserPrincipalLookupService(); UserPrincipal joe = lookupService.lookupPrincipalByName("joe"); Files.setOwner(path, joe);
- Parameters:
path
- A file reference that locates the fileowner
- The new file owner- Throws:
UnsupportedOperationException
- if the associated file system does not support theFileOwnerAttributeView
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, it deniesRuntimePermission
("accessUserInformation") or itscheckWrite
method denies write access to the file.- See Also:
FileSystem.getUserPrincipalLookupService()
,UserPrincipalLookupService
-
isSymbolicLink
public static boolean isSymbolicLink(Path path)
Tests whether a file is a symbolic link.Where is it required to distinguish an I/O exception from the case that the file is not a symbolic link then the file attributes can be read with the
readAttributes
method and the file type tested with theBasicFileAttributes.isSymbolicLink()
method.- Returns:
true
if the file is a symbolic link;false
if the file does not exist, is not a symbolic link, or it cannot be determined if the file is a symbolic link or not.- Throws:
SecurityException
- In the case of the default provider, and a security manager is installed, itscheckRead
method denies read access to the file.
-
isDirectory
public static boolean isDirectory(Path path, LinkOption... options)
Tests whether a file is a directory.The
options
array may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed and the file attribute of the final target of the link is read. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.Where is it required to distinguish an I/O exception from the case that the file is not a directory then the file attributes can be read with the
readAttributes
method and the file type tested with theBasicFileAttributes.isDirectory()
method.- Parameters:
path
- the path to the file to testoptions
- options indicating how symbolic links are handled- Returns:
true
if the file is a directory;false
if the file does not exist, is not a directory, or it cannot be determined if the file is a directory or not.- Throws:
SecurityException
- In the case of the default provider, and a security manager is installed, itscheckRead
method denies read access to the file.
-
isRegularFile
public static boolean isRegularFile(Path path, LinkOption... options)
Tests whether a file is a regular file with opaque content.The
options
array may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed and the file attribute of the final target of the link is read. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.Where is it required to distinguish an I/O exception from the case that the file is not a regular file then the file attributes can be read with the
readAttributes
method and the file type tested with theBasicFileAttributes.isRegularFile()
method.- Parameters:
path
- the path to the fileoptions
- options indicating how symbolic links are handled- Returns:
true
if the file is a regular file;false
if the file does not exist, is not a regular file, or it cannot be determined if the file is a regular file or not.- Throws:
SecurityException
- In the case of the default provider, and a security manager is installed, itscheckRead
method denies read access to the file.
-
getLastModifiedTime
public static FileTime getLastModifiedTime(Path path, LinkOption... options) throws IOException
Returns a file's last modified time.The
options
array may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed and the file attribute of the final target of the link is read. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.- Parameters:
path
- the path to the fileoptions
- options indicating how symbolic links are handled- Returns:
- a
FileTime
representing the time the file was last modified, or an implementation specific default when a time stamp to indicate the time of last modification is not supported by the file system - Throws:
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, itscheckRead
method denies read access to the file.- See Also:
BasicFileAttributes.lastModifiedTime()
-
setLastModifiedTime
public static Path setLastModifiedTime(Path path, FileTime time) throws IOException
Updates a file's last modified time attribute. The file time is converted to the epoch and precision supported by the file system. Converting from finer to coarser granularities result in precision loss. The behavior of this method when attempting to set the last modified time when it is not supported by the file system or is outside the range supported by the underlying file store is not defined. It may or not fail by throwing anIOException
.Usage Example: Suppose we want to set the last modified time to the current time:
Path path = ... FileTime now = FileTime.fromMillis(System.currentTimeMillis()); Files.setLastModifiedTime(path, now);
- Parameters:
path
- the path to the filetime
- the new last modified time- Returns:
- the file
- Throws:
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, the security manager'scheckWrite
method is invoked to check write access to file- See Also:
BasicFileAttributeView.setTimes(java.nio.file.attribute.FileTime, java.nio.file.attribute.FileTime, java.nio.file.attribute.FileTime)
-
size
public static long size(Path path) throws IOException
Returns the size of a file (in bytes). The size may differ from the actual size on the file system due to compression, support for sparse files, or other reasons. The size of files that are notregular
files is implementation specific and therefore unspecified.- Parameters:
path
- the path to the file- Returns:
- the file size, in bytes
- Throws:
IOException
- if an I/O error occursSecurityException
- In the case of the default provider, and a security manager is installed, itscheckRead
method denies read access to the file.- See Also:
BasicFileAttributes.size()
-
exists
public static boolean exists(Path path, LinkOption... options)
Tests whether a file exists.The
options
parameter may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.Note that the result of this method is immediately outdated. If this method indicates the file exists then there is no guarantee that a subsequence access will succeed. Care should be taken when using this method in security sensitive applications.
- Parameters:
path
- the path to the file to testoptions
- options indicating how symbolic links are handled .- Returns:
true
if the file exists;false
if the file does not exist or its existence cannot be determined.- Throws:
SecurityException
- In the case of the default provider, theSecurityManager.checkRead(String)
is invoked to check read access to the file.- See Also:
notExists(java.nio.file.Path, java.nio.file.LinkOption...)
-
notExists
public static boolean notExists(Path path, LinkOption... options)
Tests whether the file located by this path does not exist. This method is intended for cases where it is required to take action when it can be confirmed that a file does not exist.The
options
parameter may be used to indicate how symbolic links are handled for the case that the file is a symbolic link. By default, symbolic links are followed. If the optionNOFOLLOW_LINKS
is present then symbolic links are not followed.Note that this method is not the complement of the
exists
method. Where it is not possible to determine if a file exists or not then both methods returnfalse
. As with theexists
method, the result of this method is immediately outdated. If this method indicates the file does exist then there is no guarantee that a subsequence attempt to create the file will succeed. Care should be taken when using this method in security sensitive applications.- Parameters:
path
- the path to the file to testoptions
- options indicating how symbolic links are handled- Returns:
true
if the file does not exist;false
if the file exists or its existence cannot be determined- Throws:
SecurityException
- In the case of the default provider, theSecurityManager.checkRead(String)
is invoked to check read access to the file.
-
isReadable
public static boolean isReadable(Path path)
Tests whether a file is readable. This method checks that a file exists and that this Java virtual machine has appropriate privileges that would allow it open the file for reading. Depending on the implementation, this method may require to read file permissions, access control lists, or other file attributes in order to check the effective access to the file. Consequently, this method may not be atomic with respect to other file system operations.Note that the result of this method is immediately outdated, there is no guarantee that a subsequent attempt to open the file for reading will succeed (or even that it will access the same file). Care should be taken when using this method in security sensitive applications.
- Parameters:
path
- the path to the file to check- Returns:
true
if the file exists and is readable;false
if the file does not exist, read access would be denied because the Java virtual machine has insufficient privileges, or access cannot be determined- Throws:
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
is invoked to check read access to the file.
-
isWritable
public static boolean isWritable(Path path)
Tests whether a file is writable. This method checks that a file exists and that this Java virtual machine has appropriate privileges that would allow it open the file for writing. Depending on the implementation, this method may require to read file permissions, access control lists, or other file attributes in order to check the effective access to the file. Consequently, this method may not be atomic with respect to other file system operations.Note that result of this method is immediately outdated, there is no guarantee that a subsequent attempt to open the file for writing will succeed (or even that it will access the same file). Care should be taken when using this method in security sensitive applications.
- Parameters:
path
- the path to the file to check- Returns:
true
if the file exists and is writable;false
if the file does not exist, write access would be denied because the Java virtual machine has insufficient privileges, or access cannot be determined- Throws:
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
is invoked to check write access to the file.
-
isExecutable
public static boolean isExecutable(Path path)
Tests whether a file is executable. This method checks that a file exists and that this Java virtual machine has appropriate privileges toexecute
the file. The semantics may differ when checking access to a directory. For example, on UNIX systems, checking for execute access checks that the Java virtual machine has permission to search the directory in order to access file or subdirectories.Depending on the implementation, this method may require to read file permissions, access control lists, or other file attributes in order to check the effective access to the file. Consequently, this method may not be atomic with respect to other file system operations.
Note that the result of this method is immediately outdated, there is no guarantee that a subsequent attempt to execute the file will succeed (or even that it will access the same file). Care should be taken when using this method in security sensitive applications.
- Parameters:
path
- the path to the file to check- Returns:
true
if the file exists and is executable;false
if the file does not exist, execute access would be denied because the Java virtual machine has insufficient privileges, or access cannot be determined- Throws:
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckExec
is invoked to check execute access to the file.
-
walkFileTree
public static Path walkFileTree(Path start, Set<FileVisitOption> options, int maxDepth, FileVisitor<? super Path> visitor) throws IOException
Walks a file tree.This method walks a file tree rooted at a given starting file. The file tree traversal is depth-first with the given
FileVisitor
invoked for each file encountered. File tree traversal completes when all accessible files in the tree have been visited, or a visit method returns a result ofTERMINATE
. Where a visit method terminates due anIOException
, an uncaught error, or runtime exception, then the traversal is terminated and the error or exception is propagated to the caller of this method.For each file encountered this method attempts to read its
BasicFileAttributes
. If the file is not a directory then thevisitFile
method is invoked with the file attributes. If the file attributes cannot be read, due to an I/O exception, then thevisitFileFailed
method is invoked with the I/O exception.Where the file is a directory, and the directory could not be opened, then the
visitFileFailed
method is invoked with the I/O exception, after which, the file tree walk continues, by default, at the next sibling of the directory.Where the directory is opened successfully, then the entries in the directory, and their descendants are visited. When all entries have been visited, or an I/O error occurs during iteration of the directory, then the directory is closed and the visitor's
postVisitDirectory
method is invoked. The file tree walk then continues, by default, at the next sibling of the directory.By default, symbolic links are not automatically followed by this method. If the
options
parameter contains theFOLLOW_LINKS
option then symbolic links are followed. When following links, and the attributes of the target cannot be read, then this method attempts to get theBasicFileAttributes
of the link. If they can be read then thevisitFile
method is invoked with the attributes of the link (otherwise thevisitFileFailed
method is invoked as specified above).If the
options
parameter contains theFOLLOW_LINKS
option then this method keeps track of directories visited so that cycles can be detected. A cycle arises when there is an entry in a directory that is an ancestor of the directory. Cycle detection is done by recording thefile-key
of directories, or if file keys are not available, by invoking theisSameFile
method to test if a directory is the same file as an ancestor. When a cycle is detected it is treated as an I/O error, and thevisitFileFailed
method is invoked with an instance ofFileSystemLoopException
.The
maxDepth
parameter is the maximum number of levels of directories to visit. A value of0
means that only the starting file is visited, unless denied by the security manager. A value ofMAX_VALUE
may be used to indicate that all levels should be visited. ThevisitFile
method is invoked for all files, including directories, encountered atmaxDepth
, unless the basic file attributes cannot be read, in which case thevisitFileFailed
method is invoked.If a visitor returns a result of
null
thenNullPointerException
is thrown.When a security manager is installed and it denies access to a file (or directory), then it is ignored and the visitor is not invoked for that file (or directory).
- Parameters:
start
- the starting fileoptions
- options to configure the traversalmaxDepth
- the maximum number of directory levels to visitvisitor
- the file visitor to invoke for each file- Returns:
- the starting file
- Throws:
IllegalArgumentException
- if themaxDepth
parameter is negativeSecurityException
- If the security manager denies access to the starting file. In the case of the default provider, thecheckRead
method is invoked to check read access to the directory.IOException
- if an I/O error is thrown by a visitor method
-
walkFileTree
public static Path walkFileTree(Path start, FileVisitor<? super Path> visitor) throws IOException
Walks a file tree.This method works as if invoking it were equivalent to evaluating the expression:
In other words, it does not follow symbolic links, and visits all levels of the file tree.walkFileTree(start, EnumSet.noneOf(FileVisitOption.class), Integer.MAX_VALUE, visitor)
- Parameters:
start
- the starting filevisitor
- the file visitor to invoke for each file- Returns:
- the starting file
- Throws:
SecurityException
- If the security manager denies access to the starting file. In the case of the default provider, thecheckRead
method is invoked to check read access to the directory.IOException
- if an I/O error is thrown by a visitor method
-
newBufferedReader
public static BufferedReader newBufferedReader(Path path, Charset cs) throws IOException
Opens a file for reading, returning aBufferedReader
that may be used to read text from the file in an efficient manner. Bytes from the file are decoded into characters using the specified charset. Reading commences at the beginning of the file.The
Reader
methods that read from the file throwIOException
if a malformed or unmappable byte sequence is read.- Parameters:
path
- the path to the filecs
- the charset to use for decoding- Returns:
- a new buffered reader, with default buffer size, to read text from the file
- Throws:
IOException
- if an I/O error occurs opening the fileSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.- See Also:
readAllLines(java.nio.file.Path, java.nio.charset.Charset)
-
newBufferedWriter
public static BufferedWriter newBufferedWriter(Path path, Charset cs, OpenOption... options) throws IOException
Opens or creates a file for writing, returning aBufferedWriter
that may be used to write text to the file in an efficient manner. Theoptions
parameter specifies how the the file is created or opened. If no options are present then this method works as if theCREATE
,TRUNCATE_EXISTING
, andWRITE
options are present. In other words, it opens the file for writing, creating the file if it doesn't exist, or initially truncating an existingregular-file
to a size of0
if it exists.The
Writer
methods to write text throwIOException
if the text cannot be encoded using the specified charset.- Parameters:
path
- the path to the filecs
- the charset to use for encodingoptions
- options specifying how the file is opened- Returns:
- a new buffered writer, with default buffer size, to write text to the file
- Throws:
IOException
- if an I/O error occurs opening or creating the fileUnsupportedOperationException
- if an unsupported option is specifiedSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the file.- See Also:
write(Path,Iterable,Charset,OpenOption[])
-
copy
public static long copy(InputStream in, Path target, CopyOption... options) throws IOException
Copies all bytes from an input stream to a file. On return, the input stream will be at end of stream.By default, the copy fails if the target file already exists or is a symbolic link. If the
REPLACE_EXISTING
option is specified, and the target file already exists, then it is replaced if it is not a non-empty directory. If the target file exists and is a symbolic link, then the symbolic link is replaced. In this release, theREPLACE_EXISTING
option is the only option required to be supported by this method. Additional options may be supported in future releases.If an I/O error occurs reading from the input stream or writing to the file, then it may do so after the target file has been created and after some bytes have been read or written. Consequently the input stream may not be at end of stream and may be in an inconsistent state. It is strongly recommended that the input stream be promptly closed if an I/O error occurs.
This method may block indefinitely reading from the input stream (or writing to the file). The behavior for the case that the input stream is asynchronously closed or the thread interrupted during the copy is highly input stream and file system provider specific and therefore not specified.
Usage example: Suppose we want to capture a web page and save it to a file:
Path path = ... URI u = URI.create("http://java.sun.com/"); try (InputStream in = u.toURL().openStream()) { Files.copy(in, path); }
- Parameters:
in
- the input stream to read fromtarget
- the path to the fileoptions
- options specifying how the copy should be done- Returns:
- the number of bytes read or written
- Throws:
IOException
- if an I/O error occurs when reading or writingFileAlreadyExistsException
- if the target file exists but cannot be replaced because theREPLACE_EXISTING
option is not specified (optional specific exception)DirectoryNotEmptyException
- theREPLACE_EXISTING
option is specified but the file cannot be replaced because it is a non-empty directory (optional specific exception) *UnsupportedOperationException
- ifoptions
contains a copy option that is not supportedSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the file. Where theREPLACE_EXISTING
option is specified, the security manager'scheckDelete
method is invoked to check that an existing file can be deleted.
-
copy
public static long copy(Path source, OutputStream out) throws IOException
Copies all bytes from a file to an output stream.If an I/O error occurs reading from the file or writing to the output stream, then it may do so after some bytes have been read or written. Consequently the output stream may be in an inconsistent state. It is strongly recommended that the output stream be promptly closed if an I/O error occurs.
This method may block indefinitely writing to the output stream (or reading from the file). The behavior for the case that the output stream is asynchronously closed or the thread interrupted during the copy is highly output stream and file system provider specific and therefore not specified.
Note that if the given output stream is
Flushable
then itsflush
method may need to invoked after this method completes so as to flush any buffered output.- Parameters:
source
- the path to the fileout
- the output stream to write to- Returns:
- the number of bytes read or written
- Throws:
IOException
- if an I/O error occurs when reading or writingSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.
-
readAllBytes
public static byte[] readAllBytes(Path path) throws IOException
Reads all the bytes from a file. The method ensures that the file is closed when all bytes have been read or an I/O error, or other runtime exception, is thrown.Note that this method is intended for simple cases where it is convenient to read all bytes into a byte array. It is not intended for reading in large files.
- Parameters:
path
- the path to the file- Returns:
- a byte array containing the bytes read from the file
- Throws:
IOException
- if an I/O error occurs reading from the streamOutOfMemoryError
- if an array of the required size cannot be allocated, for example the file is larger that2GB
SecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.
-
readAllLines
public static List<String> readAllLines(Path path, Charset cs) throws IOException
Read all lines from a file. This method ensures that the file is closed when all bytes have been read or an I/O error, or other runtime exception, is thrown. Bytes from the file are decoded into characters using the specified charset.This method recognizes the following as line terminators:
-
\u000D
followed by\u000A
, CARRIAGE RETURN followed by LINE FEED -
\u000A
, LINE FEED -
\u000D
, CARRIAGE RETURN
Additional Unicode line terminators may be recognized in future releases.
Note that this method is intended for simple cases where it is convenient to read all lines in a single operation. It is not intended for reading in large files.
- Parameters:
path
- the path to the filecs
- the charset to use for decoding- Returns:
- the lines from the file as a
List
; whether theList
is modifiable or not is implementation dependent and therefore not specified - Throws:
IOException
- if an I/O error occurs reading from the file or a malformed or unmappable byte sequence is readSecurityException
- In the case of the default provider, and a security manager is installed, thecheckRead
method is invoked to check read access to the file.- See Also:
newBufferedReader(java.nio.file.Path, java.nio.charset.Charset)
-
-
write
public static Path write(Path path, byte[] bytes, OpenOption... options) throws IOException
Writes bytes to a file. Theoptions
parameter specifies how the the file is created or opened. If no options are present then this method works as if theCREATE
,TRUNCATE_EXISTING
, andWRITE
options are present. In other words, it opens the file for writing, creating the file if it doesn't exist, or initially truncating an existingregular-file
to a size of0
. All bytes in the byte array are written to the file. The method ensures that the file is closed when all bytes have been written (or an I/O error or other runtime exception is thrown). If an I/O error occurs then it may do so after the file has created or truncated, or after some bytes have been written to the file.Usage example: By default the method creates a new file or overwrites an existing file. Suppose you instead want to append bytes to an existing file:
Path path = ... byte[] bytes = ... Files.write(path, bytes, StandardOpenOption.APPEND);
- Parameters:
path
- the path to the filebytes
- the byte array with the bytes to writeoptions
- options specifying how the file is opened- Returns:
- the path
- Throws:
IOException
- if an I/O error occurs writing to or creating the fileUnsupportedOperationException
- if an unsupported option is specifiedSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the file.
-
write
public static Path write(Path path, Iterable<? extends CharSequence> lines, Charset cs, OpenOption... options) throws IOException
Write lines of text to a file. Each line is a char sequence and is written to the file in sequence with each line terminated by the platform's line separator, as defined by the system propertyline.separator
. Characters are encoded into bytes using the specified charset.The
options
parameter specifies how the the file is created or opened. If no options are present then this method works as if theCREATE
,TRUNCATE_EXISTING
, andWRITE
options are present. In other words, it opens the file for writing, creating the file if it doesn't exist, or initially truncating an existingregular-file
to a size of0
. The method ensures that the file is closed when all lines have been written (or an I/O error or other runtime exception is thrown). If an I/O error occurs then it may do so after the file has created or truncated, or after some bytes have been written to the file.- Parameters:
path
- the path to the filelines
- an object to iterate over the char sequencescs
- the charset to use for encodingoptions
- options specifying how the file is opened- Returns:
- the path
- Throws:
IOException
- if an I/O error occurs writing to or creating the file, or the text cannot be encoded using the specified charsetUnsupportedOperationException
- if an unsupported option is specifiedSecurityException
- In the case of the default provider, and a security manager is installed, thecheckWrite
method is invoked to check write access to the file.
-
-
Traduction non disponible
Les API Java ne sont pas encore traduites en français sur l'infobrol. Seule la version anglaise est disponible pour l'instant.
Version en cache
24/11/2024 13:21:53 Cette version de la page est en cache (à la date du 24/11/2024 13:21:53) afin d'accélérer le traitement. Vous pouvez activer le mode utilisateur dans le menu en haut pour afficher la dernère version de la page.Document créé le 11/06/2005, dernière modification le 04/03/2020
Source du document imprimé : https://www.gaudry.be/java-api-rf-java/nio/file/Files.html
L'infobrol est un site personnel dont le contenu n'engage que moi. Le texte est mis à disposition sous licence CreativeCommons(BY-NC-SA). Plus d'info sur les conditions d'utilisation et sur l'auteur.
Références
Ces références et liens indiquent des documents consultés lors de la rédaction de cette page, ou qui peuvent apporter un complément d'information, mais les auteurs de ces sources ne peuvent être tenus responsables du contenu de cette page.
L'auteur de ce site est seul responsable de la manière dont sont présentés ici les différents concepts, et des libertés qui sont prises avec les ouvrages de référence. N'oubliez pas que vous devez croiser les informations de sources multiples afin de diminuer les risques d'erreurs.