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Interface Blob

All Known Implementing Classes:

SerialBlob

public interfaceBlob

The representation (mapping) in the Java 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 interfacesResultSet,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 theBlob interface must be fully implemented if the JDBC driver supports the data type.

Since:

1.2

length

longlength()            throwsSQLException

Returns the number of bytes in theBLOB value designated by thisBlob object.

Returns:

length of theBLOB 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)                throwsSQLException

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 1

length - the number of consecutive bytes to be copied; the value for length must be 0 or greater

Returns:

a byte array containing up tolength 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 0

SQLFeatureNotSupportedException - if the JDBC driver does not support this method

Since:

1.2

See Also:

setBytes(long, byte[])

getBinaryStream

InputStreamgetBinaryStream()                            throwsSQLException

Retrieves theBLOB value designated by thisBlob instance as a stream.

Returns:

a stream containing theBLOB data

Throws:

SQLException - if there is an error accessing theBLOB value

SQLFeatureNotSupportedException - if the JDBC driver does not support this method

Since:

1.2

See Also:

setBinaryStream(long)

position

longposition(byte[] pattern,              long start)              throwsSQLException

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 search

start - 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 1

SQLFeatureNotSupportedException - if the JDBC driver does not support this method

Since:

1.2

position

longposition(Blob pattern,              long start)              throwsSQLException

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 search

start - 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 1

SQLFeatureNotSupportedException - if the JDBC driver does not support this method

Since:

1.2

setBytes

intsetBytes(long pos,             byte[] bytes)             throwsSQLException

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 forpos 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 1

bytes - 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 1

SQLFeatureNotSupportedException - if the JDBC driver does not support this method

Since:

1.4

See Also:

getBytes(long, int)

setBytes

intsetBytes(long pos,             byte[] bytes,             int offset,             int len)             throwsSQLException

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 forpos 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 1

bytes - the array of bytes to be written to thisBLOB object

offset - the offset into the arraybytes at which to start reading the bytes to be set

len - 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 1

SQLFeatureNotSupportedException - if the JDBC driver does not support this method

Since:

1.4

See Also:

getBytes(long, int)

setBinaryStream

OutputStreamsetBinaryStream(long pos)                             throwsSQLException

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 forpos 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:

ajava.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 1

SQLFeatureNotSupportedException - if the JDBC driver does not support this method

Since:

1.4

See Also:

getBinaryStream()

truncate

voidtruncate(long len)              throwsSQLException

Truncates theBLOB value that thisBlob object represents to belen bytes in length.

Note: If the value specified forpos 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 0

SQLFeatureNotSupportedException - if the JDBC driver does not support this method

Since:

1.4

free

voidfree()          throwsSQLException

This method frees theBlob object and releases the resources that it holds. The object is invalid once thefree method is called.

Afterfree 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 resources

SQLFeatureNotSupportedException - if the JDBC driver does not support this method

Since:

1.6

getBinaryStream

InputStreamgetBinaryStream(long pos,                            long length)                            throwsSQLException

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 1

length - 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