-
- All Known Implementing Classes:
- SerialBlob
public interface Blob
The representation (mapping) in the JavaTM programming language of an SQLBLOB
value. An SQLBLOB
is a built-in type that stores a Binary Large Object as a column value in a row of a database table. By default drivers implementBlob
using an SQLlocator(BLOB)
, which means that aBlob
object contains a logical pointer to the SQLBLOB
data rather than the data itself. ABlob
object is valid for the duration of the transaction in which is was created.Methods in the interfaces
ResultSet
,CallableStatement
, andPreparedStatement
, such asgetBlob
andsetBlob
allow a programmer to access an SQLBLOB
value. TheBlob
interface provides methods for getting the length of an SQLBLOB
(Binary Large Object) value, for materializing aBLOB
value on the client, and for determining the position of a pattern of bytes within aBLOB
value. In addition, this interface has methods for updating aBLOB
value.All methods on the
Blob
interface must be fully implemented if the JDBC driver supports the data type.- Since:
- 1.2
-
-
Method Summary
Methods Modifier and Type Method and Description void
free()
This method frees theBlob
object and releases the resources that it holds.InputStream
getBinaryStream()
Retrieves theBLOB
value designated by thisBlob
instance as a stream.InputStream
getBinaryStream(long pos, long length)
Returns anInputStream
object that contains a partialBlob
value, starting with the byte specified by pos, which is length bytes in length.byte[]
getBytes(long pos, int length)
Retrieves all or part of theBLOB
value that thisBlob
object represents, as an array of bytes.long
length()
Returns the number of bytes in theBLOB
value designated by thisBlob
object.long
position(Blob pattern, long start)
Retrieves the byte position in theBLOB
value designated by thisBlob
object at whichpattern
begins.long
position(byte[] pattern, long start)
Retrieves the byte position at which the specified byte arraypattern
begins within theBLOB
value that thisBlob
object represents.OutputStream
setBinaryStream(long pos)
Retrieves a stream that can be used to write to theBLOB
value that thisBlob
object represents.int
setBytes(long pos, byte[] bytes)
Writes the given array of bytes to theBLOB
value that thisBlob
object represents, starting at positionpos
, and returns the number of bytes written.int
setBytes(long pos, byte[] bytes, int offset, int len)
Writes all or part of the givenbyte
array to theBLOB
value that thisBlob
object represents and returns the number of bytes written.void
truncate(long len)
Truncates theBLOB
value that thisBlob
object represents to belen
bytes in length.
-
-
-
Method Detail
-
length
long length() throws SQLException
Returns the number of bytes in theBLOB
value designated by thisBlob
object.- Returns:
- length of the
BLOB
in bytes - Throws:
SQLException
- if there is an error accessing the length of theBLOB
SQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.2
-
getBytes
byte[] getBytes(long pos, int length) throws SQLException
Retrieves all or part of theBLOB
value that thisBlob
object represents, as an array of bytes. Thisbyte
array contains up tolength
consecutive bytes starting at positionpos
.- Parameters:
pos
- the ordinal position of the first byte in theBLOB
value to be extracted; the first byte is at position 1length
- the number of consecutive bytes to be copied; the value for length must be 0 or greater- Returns:
- a byte array containing up to
length
consecutive bytes from theBLOB
value designated by thisBlob
object, starting with the byte at positionpos
- Throws:
SQLException
- if there is an error accessing theBLOB
value; if pos is less than 1 or length is less than 0SQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.2
- See Also:
setBytes(long, byte[])
-
getBinaryStream
InputStream getBinaryStream() throws SQLException
Retrieves theBLOB
value designated by thisBlob
instance as a stream.- Returns:
- a stream containing the
BLOB
data - Throws:
SQLException
- if there is an error accessing theBLOB
valueSQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.2
- See Also:
setBinaryStream(long)
-
position
long position(byte[] pattern, long start) throws SQLException
Retrieves the byte position at which the specified byte arraypattern
begins within theBLOB
value that thisBlob
object represents. The search forpattern
begins at positionstart
.- Parameters:
pattern
- the byte array for which to searchstart
- the position at which to begin searching; the first position is 1- Returns:
- the position at which the pattern appears, else -1
- Throws:
SQLException
- if there is an error accessing theBLOB
or if start is less than 1SQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.2
-
position
long position(Blob pattern, long start) throws SQLException
Retrieves the byte position in theBLOB
value designated by thisBlob
object at whichpattern
begins. The search begins at positionstart
.- Parameters:
pattern
- theBlob
object designating theBLOB
value for which to searchstart
- the position in theBLOB
value at which to begin searching; the first position is 1- Returns:
- the position at which the pattern begins, else -1
- Throws:
SQLException
- if there is an error accessing theBLOB
value or if start is less than 1SQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.2
-
setBytes
int setBytes(long pos, byte[] bytes) throws SQLException
Writes the given array of bytes to theBLOB
value that thisBlob
object represents, starting at positionpos
, and returns the number of bytes written. The array of bytes will overwrite the existing bytes in theBlob
object starting at the positionpos
. If the end of theBlob
value is reached while writing the array of bytes, then the length of theBlob
value will be increased to accomodate the extra bytes.Note: If the value specified for
pos
is greater then the length+1 of theBLOB
value then the behavior is undefined. Some JDBC drivers may throw aSQLException
while other drivers may support this operation.- Parameters:
pos
- the position in theBLOB
object at which to start writing; the first position is 1bytes
- the array of bytes to be written to theBLOB
value that thisBlob
object represents- Returns:
- the number of bytes written
- Throws:
SQLException
- if there is an error accessing theBLOB
value or if pos is less than 1SQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.4
- See Also:
getBytes(long, int)
-
setBytes
int setBytes(long pos, byte[] bytes, int offset, int len) throws SQLException
Writes all or part of the givenbyte
array to theBLOB
value that thisBlob
object represents and returns the number of bytes written. Writing starts at positionpos
in theBLOB
value;len
bytes from the given byte array are written. The array of bytes will overwrite the existing bytes in theBlob
object starting at the positionpos
. If the end of theBlob
value is reached while writing the array of bytes, then the length of theBlob
value will be increased to accomodate the extra bytes.Note: If the value specified for
pos
is greater then the length+1 of theBLOB
value then the behavior is undefined. Some JDBC drivers may throw aSQLException
while other drivers may support this operation.- Parameters:
pos
- the position in theBLOB
object at which to start writing; the first position is 1bytes
- the array of bytes to be written to thisBLOB
objectoffset
- the offset into the arraybytes
at which to start reading the bytes to be setlen
- the number of bytes to be written to theBLOB
value from the array of bytesbytes
- Returns:
- the number of bytes written
- Throws:
SQLException
- if there is an error accessing theBLOB
value or if pos is less than 1SQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.4
- See Also:
getBytes(long, int)
-
setBinaryStream
OutputStream setBinaryStream(long pos) throws SQLException
Retrieves a stream that can be used to write to theBLOB
value that thisBlob
object represents. The stream begins at positionpos
. The bytes written to the stream will overwrite the existing bytes in theBlob
object starting at the positionpos
. If the end of theBlob
value is reached while writing to the stream, then the length of theBlob
value will be increased to accomodate the extra bytes.Note: If the value specified for
pos
is greater then the length+1 of theBLOB
value then the behavior is undefined. Some JDBC drivers may throw aSQLException
while other drivers may support this operation.- Parameters:
pos
- the position in theBLOB
value at which to start writing; the first position is 1- Returns:
- a
java.io.OutputStream
object to which data can be written - Throws:
SQLException
- if there is an error accessing theBLOB
value or if pos is less than 1SQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.4
- See Also:
getBinaryStream()
-
truncate
void truncate(long len) throws SQLException
Truncates theBLOB
value that thisBlob
object represents to belen
bytes in length.Note: If the value specified for
pos
is greater then the length+1 of theBLOB
value then the behavior is undefined. Some JDBC drivers may throw aSQLException
while other drivers may support this operation.- Parameters:
len
- the length, in bytes, to which theBLOB
value that thisBlob
object represents should be truncated- Throws:
SQLException
- if there is an error accessing theBLOB
value or if len is less than 0SQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.4
-
free
void free() throws SQLException
This method frees theBlob
object and releases the resources that it holds. The object is invalid once thefree
method is called.After
free
has been called, any attempt to invoke a method other thanfree
will result in aSQLException
being thrown. Iffree
is called multiple times, the subsequent calls tofree
are treated as a no-op.- Throws:
SQLException
- if an error occurs releasing the Blob's resourcesSQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.6
-
getBinaryStream
InputStream getBinaryStream(long pos, long length) throws SQLException
Returns anInputStream
object that contains a partialBlob
value, starting with the byte specified by pos, which is length bytes in length.- Parameters:
pos
- the offset to the first byte of the partial value to be retrieved. The first byte in theBlob
is at position 1length
- the length in bytes of the partial value to be retrieved- Returns:
InputStream
through which the partialBlob
value can be read.- Throws:
SQLException
- if pos is less than 1 or if pos is greater than the number of bytes in theBlob
or if pos + length is greater than the number of bytes in theBlob
SQLFeatureNotSupportedException
- if the JDBC driver does not support this method- Since:
- 1.6
-
-
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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/sql/Blob.html
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