- java.lang.Object
-
- java.io.Writer
-
- java.io.PrintWriter
-
- All Implemented Interfaces:
- Closeable, Flushable, Appendable, AutoCloseable
public class PrintWriter extends Writer
Prints formatted representations of objects to a text-output stream. This class implements all of the print methods found inPrintStream
. It does not contain methods for writing raw bytes, for which a program should use unencoded byte streams.Unlike the
PrintStream
class, if automatic flushing is enabled it will be done only when one of the println, printf, or format methods is invoked, rather than whenever a newline character happens to be output. These methods use the platform's own notion of line separator rather than the newline character.Methods in this class never throw I/O exceptions, although some of its constructors may. The client may inquire as to whether any errors have occurred by invoking
checkError()
.- Since:
- JDK1.1
-
-
Field Summary
Fields Modifier and Type Field and Description protected Writer
out
The underlying character-output stream of thisPrintWriter
.-
Fields inherited from class java.io.Writer
lock
-
-
Constructor Summary
Constructors Constructor and Description PrintWriter(File file)
Creates a new PrintWriter, without automatic line flushing, with the specified file.PrintWriter(File file, String csn)
Creates a new PrintWriter, without automatic line flushing, with the specified file and charset.PrintWriter(OutputStream out)
Creates a new PrintWriter, without automatic line flushing, from an existing OutputStream.PrintWriter(OutputStream out, boolean autoFlush)
Creates a new PrintWriter from an existing OutputStream.PrintWriter(String fileName)
Creates a new PrintWriter, without automatic line flushing, with the specified file name.PrintWriter(String fileName, String csn)
Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset.PrintWriter(Writer out)
Creates a new PrintWriter, without automatic line flushing.PrintWriter(Writer out, boolean autoFlush)
Creates a new PrintWriter.
-
Method Summary
Methods Modifier and Type Method and Description PrintWriter
append(char c)
Appends the specified character to this writer.PrintWriter
append(CharSequence csq)
Appends the specified character sequence to this writer.PrintWriter
append(CharSequence csq, int start, int end)
Appends a subsequence of the specified character sequence to this writer.boolean
checkError()
Flushes the stream if it's not closed and checks its error state.protected void
clearError()
Clears the error state of this stream.void
close()
Closes the stream and releases any system resources associated with it.void
flush()
Flushes the stream.PrintWriter
format(Locale l, String format, Object... args)
Writes a formatted string to this writer using the specified format string and arguments.PrintWriter
format(String format, Object... args)
Writes a formatted string to this writer using the specified format string and arguments.void
print(boolean b)
Prints a boolean value.void
print(char c)
Prints a character.void
print(char[] s)
Prints an array of characters.void
print(double d)
Prints a double-precision floating-point number.void
print(float f)
Prints a floating-point number.void
print(int i)
Prints an integer.void
print(long l)
Prints a long integer.void
print(Object obj)
Prints an object.void
print(String s)
Prints a string.PrintWriter
printf(Locale l, String format, Object... args)
A convenience method to write a formatted string to this writer using the specified format string and arguments.PrintWriter
printf(String format, Object... args)
A convenience method to write a formatted string to this writer using the specified format string and arguments.void
println()
Terminates the current line by writing the line separator string.void
println(boolean x)
Prints a boolean value and then terminates the line.void
println(char x)
Prints a character and then terminates the line.void
println(char[] x)
Prints an array of characters and then terminates the line.void
println(double x)
Prints a double-precision floating-point number and then terminates the line.void
println(float x)
Prints a floating-point number and then terminates the line.void
println(int x)
Prints an integer and then terminates the line.void
println(long x)
Prints a long integer and then terminates the line.void
println(Object x)
Prints an Object and then terminates the line.void
println(String x)
Prints a String and then terminates the line.protected void
setError()
Indicates that an error has occurred.void
write(char[] buf)
Writes an array of characters.void
write(char[] buf, int off, int len)
Writes A Portion of an array of characters.void
write(int c)
Writes a single character.void
write(String s)
Writes a string.void
write(String s, int off, int len)
Writes a portion of a string.
-
-
-
Field Detail
-
out
protected Writer out
The underlying character-output stream of thisPrintWriter
.- Since:
- 1.2
-
-
Constructor Detail
-
PrintWriter
public PrintWriter(Writer out)
Creates a new PrintWriter, without automatic line flushing.- Parameters:
out
- A character-output stream
-
PrintWriter
public PrintWriter(Writer out, boolean autoFlush)
Creates a new PrintWriter.- Parameters:
out
- A character-output streamautoFlush
- A boolean; if true, the println, printf, or format methods will flush the output buffer
-
PrintWriter
public PrintWriter(OutputStream out)
Creates a new PrintWriter, without automatic line flushing, from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding.- Parameters:
out
- An output stream- See Also:
OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)
-
PrintWriter
public PrintWriter(OutputStream out, boolean autoFlush)
Creates a new PrintWriter from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding.- Parameters:
out
- An output streamautoFlush
- A boolean; if true, the println, printf, or format methods will flush the output buffer- See Also:
OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)
-
PrintWriter
public PrintWriter(String fileName) throws FileNotFoundException
Creates a new PrintWriter, without automatic line flushing, with the specified file name. This convenience constructor creates the necessary intermediateOutputStreamWriter
, which will encode characters using the default charset for this instance of the Java virtual machine.- Parameters:
fileName
- The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.- Throws:
FileNotFoundException
- If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the fileSecurityException
- If a security manager is present andcheckWrite(fileName)
denies write access to the file- Since:
- 1.5
-
PrintWriter
public PrintWriter(String fileName, String csn) throws FileNotFoundException, UnsupportedEncodingException
Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter
, which will encode characters using the provided charset.- Parameters:
fileName
- The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.csn
- The name of a supported charset- Throws:
FileNotFoundException
- If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the fileSecurityException
- If a security manager is present andcheckWrite(fileName)
denies write access to the fileUnsupportedEncodingException
- If the named charset is not supported- Since:
- 1.5
-
PrintWriter
public PrintWriter(File file) throws FileNotFoundException
Creates a new PrintWriter, without automatic line flushing, with the specified file. This convenience constructor creates the necessary intermediateOutputStreamWriter
, which will encode characters using the default charset for this instance of the Java virtual machine.- Parameters:
file
- The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.- Throws:
FileNotFoundException
- If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the fileSecurityException
- If a security manager is present andcheckWrite(file.getPath())
denies write access to the file- Since:
- 1.5
-
PrintWriter
public PrintWriter(File file, String csn) throws FileNotFoundException, UnsupportedEncodingException
Creates a new PrintWriter, without automatic line flushing, with the specified file and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter
, which will encode characters using the provided charset.- Parameters:
file
- The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.csn
- The name of a supported charset- Throws:
FileNotFoundException
- If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the fileSecurityException
- If a security manager is present andcheckWrite(file.getPath())
denies write access to the fileUnsupportedEncodingException
- If the named charset is not supported- Since:
- 1.5
-
-
Method Detail
-
flush
public void flush()
Flushes the stream.- Specified by:
flush
in interfaceFlushable
- Specified by:
flush
in classWriter
- See Also:
checkError()
-
close
public void close()
Closes the stream and releases any system resources associated with it. Closing a previously closed stream has no effect.- Specified by:
close
in interfaceCloseable
- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in classWriter
- See Also:
checkError()
-
checkError
public boolean checkError()
Flushes the stream if it's not closed and checks its error state.- Returns:
true
if the print stream has encountered an error, either on the underlying output stream or during a format conversion.
-
setError
protected void setError()
Indicates that an error has occurred.This method will cause subsequent invocations of
checkError()
to return true untilclearError()
is invoked.
-
clearError
protected void clearError()
Clears the error state of this stream.This method will cause subsequent invocations of
checkError()
to return false until another write operation fails and invokessetError()
.- Since:
- 1.6
-
write
public void write(int c)
Writes a single character.
-
write
public void write(char[] buf, int off, int len)
Writes A Portion of an array of characters.
-
write
public void write(char[] buf)
Writes an array of characters. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.
-
write
public void write(String s, int off, int len)
Writes a portion of a string.
-
write
public void write(String s)
Writes a string. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.
-
print
public void print(boolean b)
Prints a boolean value. The string produced by
is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of theString.valueOf(boolean)
method.write(int)
- Parameters:
b
- Theboolean
to be printed
-
print
public void print(char c)
Prints a character. The character is translated into one or more bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the
method.write(int)
- Parameters:
c
- Thechar
to be printed
-
print
public void print(int i)
Prints an integer. The string produced by
is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of theString.valueOf(int)
method.write(int)
- Parameters:
i
- Theint
to be printed- See Also:
Integer.toString(int)
-
print
public void print(long l)
Prints a long integer. The string produced by
is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of theString.valueOf(long)
method.write(int)
- Parameters:
l
- Thelong
to be printed- See Also:
Long.toString(long)
-
print
public void print(float f)
Prints a floating-point number. The string produced by
is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of theString.valueOf(float)
method.write(int)
- Parameters:
f
- Thefloat
to be printed- See Also:
Float.toString(float)
-
print
public void print(double d)
Prints a double-precision floating-point number. The string produced by
is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of theString.valueOf(double)
method.write(int)
- Parameters:
d
- Thedouble
to be printed- See Also:
Double.toString(double)
-
print
public void print(char[] s)
Prints an array of characters. The characters are converted into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the
method.write(int)
- Parameters:
s
- The array of chars to be printed- Throws:
NullPointerException
- Ifs
isnull
-
print
public void print(String s)
Prints a string. If the argument isnull
then the string"null"
is printed. Otherwise, the string's characters are converted into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the
method.write(int)
- Parameters:
s
- TheString
to be printed
-
print
public void print(Object obj)
Prints an object. The string produced by the
method is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of theString.valueOf(Object)
method.write(int)
- Parameters:
obj
- TheObject
to be printed- See Also:
Object.toString()
-
println
public void println()
Terminates the current line by writing the line separator string. The line separator string is defined by the system propertyline.separator
, and is not necessarily a single newline character ('\n'
).
-
println
public void println(boolean x)
Prints a boolean value and then terminates the line. This method behaves as though it invokes
and thenprint(boolean)
.println()
- Parameters:
x
- theboolean
value to be printed
-
println
public void println(char x)
Prints a character and then terminates the line. This method behaves as though it invokes
and thenprint(char)
.println()
- Parameters:
x
- thechar
value to be printed
-
println
public void println(int x)
Prints an integer and then terminates the line. This method behaves as though it invokes
and thenprint(int)
.println()
- Parameters:
x
- theint
value to be printed
-
println
public void println(long x)
Prints a long integer and then terminates the line. This method behaves as though it invokes
and thenprint(long)
.println()
- Parameters:
x
- thelong
value to be printed
-
println
public void println(float x)
Prints a floating-point number and then terminates the line. This method behaves as though it invokes
and thenprint(float)
.println()
- Parameters:
x
- thefloat
value to be printed
-
println
public void println(double x)
Prints a double-precision floating-point number and then terminates the line. This method behaves as though it invokes
and thenprint(double)
.println()
- Parameters:
x
- thedouble
value to be printed
-
println
public void println(char[] x)
Prints an array of characters and then terminates the line. This method behaves as though it invokes
and thenprint(char[])
.println()
- Parameters:
x
- the array ofchar
values to be printed
-
println
public void println(String x)
Prints a String and then terminates the line. This method behaves as though it invokes
and thenprint(String)
.println()
- Parameters:
x
- theString
value to be printed
-
println
public void println(Object x)
Prints an Object and then terminates the line. This method calls at first String.valueOf(x) to get the printed object's string value, then behaves as though it invokes
and thenprint(String)
.println()
- Parameters:
x
- TheObject
to be printed.
-
printf
public PrintWriter printf(String format, Object... args)
A convenience method to write a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer.An invocation of this method of the form out.printf(format, args) behaves in exactly the same way as the invocation
out.format(format, args)
- Parameters:
format
- A format string as described in Format string syntax.args
- Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.- Returns:
- This writer
- Throws:
IllegalFormatException
- If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.NullPointerException
- If the format is null- Since:
- 1.5
-
printf
public PrintWriter printf(Locale l, String format, Object... args)
A convenience method to write a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer.An invocation of this method of the form out.printf(l, format, args) behaves in exactly the same way as the invocation
out.format(l, format, args)
- Parameters:
l
- The locale to apply during formatting. If l is null then no localization is applied.format
- A format string as described in Format string syntax.args
- Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.- Returns:
- This writer
- Throws:
IllegalFormatException
- If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.NullPointerException
- If the format is null- Since:
- 1.5
-
format
public PrintWriter format(String format, Object... args)
Writes a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer.The locale always used is the one returned by
Locale.getDefault()
, regardless of any previous invocations of other formatting methods on this object.- Parameters:
format
- A format string as described in Format string syntax.args
- Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.- Returns:
- This writer
- Throws:
IllegalFormatException
- If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the Formatter class specification.NullPointerException
- If the format is null- Since:
- 1.5
-
format
public PrintWriter format(Locale l, String format, Object... args)
Writes a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer.- Parameters:
l
- The locale to apply during formatting. If l is null then no localization is applied.format
- A format string as described in Format string syntax.args
- Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by The Java™ Virtual Machine Specification. The behaviour on a null argument depends on the conversion.- Returns:
- This writer
- Throws:
IllegalFormatException
- If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.NullPointerException
- If the format is null- Since:
- 1.5
-
append
public PrintWriter append(CharSequence csq)
Appends the specified character sequence to this writer.An invocation of this method of the form out.append(csq) behaves in exactly the same way as the invocation
out.write(csq.toString())
Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking the toString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.
- Specified by:
append
in interfaceAppendable
- Overrides:
append
in classWriter
- Parameters:
csq
- The character sequence to append. If csq is null, then the four characters "null" are appended to this writer.- Returns:
- This writer
- Since:
- 1.5
-
append
public PrintWriter append(CharSequence csq, int start, int end)
Appends a subsequence of the specified character sequence to this writer.An invocation of this method of the form out.append(csq, start, end) when csq is not null, behaves in exactly the same way as the invocation
out.write(csq.subSequence(start, end).toString())
- Specified by:
append
in interfaceAppendable
- Overrides:
append
in classWriter
- Parameters:
csq
- The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null".start
- The index of the first character in the subsequenceend
- The index of the character following the last character in the subsequence- Returns:
- This writer
- Throws:
IndexOutOfBoundsException
- If start or end are negative, start is greater than end, or end is greater than csq.length()- Since:
- 1.5
-
append
public PrintWriter append(char c)
Appends the specified character to this writer.An invocation of this method of the form out.append(c) behaves in exactly the same way as the invocation
out.write(c)
- Specified by:
append
in interfaceAppendable
- Overrides:
append
in classWriter
- Parameters:
c
- The 16-bit character to append- Returns:
- This writer
- Since:
- 1.5
-
-
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Dokument erstellt 11/06/2005, zuletzt geändert 04/03/2020
Quelle des gedruckten Dokuments:https://www.gaudry.be/de/java-api-rf-java/io/PrintWriter.html
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