org.springframework.jdbc.support.lob

Class DefaultLobHandler

java.lang.Object

org.springframework.jdbc.support.lob.AbstractLobHandler

org.springframework.jdbc.support.lob.DefaultLobHandler

All Implemented Interfaces:

LobHandler

public class DefaultLobHandler
extends AbstractLobHandler

Default implementation of the LobHandler interface. Invokes the direct accessor methods that java.sql.ResultSet and java.sql.PreparedStatement offer.

By default, incoming streams are going to be passed to the appropriate setBinary/Ascii/CharacterStream method on the JDBC driver's PreparedStatement. If the specified content length is negative, this handler will use the JDBC 4.0 variants of the set-stream methods without a length parameter; otherwise, it will pass the specified length on to the driver.

This LobHandler should work for any JDBC driver that is JDBC compliant in terms of the spec's suggestions regarding simple BLOB and CLOB handling. This does not apply to Oracle 9i's drivers at all; as of Oracle 10g, it does work but may still come with LOB size limitations. Consider using recent Oracle drivers even when working against an older database server. See the LobHandler javadoc for the full set of recommendations.

Some JDBC drivers require values with a BLOB/CLOB target column to be explicitly set through the JDBC setBlob / setClob API: for example, PostgreSQL's driver. Switch the "wrapAsLob" property to "true" when operating against such a driver.

On JDBC 4.0, this LobHandler also supports streaming the BLOB/CLOB content via the setBlob / setClob variants that take a stream argument directly. Consider switching the "streamAsLob" property to "true" when operating against a fully compliant JDBC 4.0 driver.

Finally, primarily as a direct equivalent to OracleLobHandler, this LobHandler also supports the creation of temporary BLOB/CLOB objects. Consider switching the "createTemporaryLob" property to "true" when "streamAsLob" happens to run into LOB size limitations.

See the LobHandler interface javadoc for a summary of recommendations.

Since:

04.12.2003

Author:

Juergen Hoeller

See Also:

ResultSet.getBytes(int), ResultSet.getBinaryStream(int), ResultSet.getString(int), ResultSet.getAsciiStream(int), ResultSet.getCharacterStream(int), PreparedStatement.setBytes(int, byte[]), PreparedStatement.setBinaryStream(int, java.io.InputStream, int), PreparedStatement.setString(int, java.lang.String), PreparedStatement.setAsciiStream(int, java.io.InputStream, int), PreparedStatement.setCharacterStream(int, java.io.Reader, int)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected class	DefaultLobHandler.DefaultLobCreator Default LobCreator implementation as an inner class.

Field Summary

Fields

Modifier and Type	Field and Description
protected Log	logger

Constructor Summary

Constructors

Constructor and Description
DefaultLobHandler()

Method Summary

Modifier and Type	Method and Description
InputStream	getBlobAsBinaryStream(ResultSet rs, int columnIndex) Retrieve the given column as binary stream from the given ResultSet.
byte[]	getBlobAsBytes(ResultSet rs, int columnIndex) Retrieve the given column as bytes from the given ResultSet.
InputStream	getClobAsAsciiStream(ResultSet rs, int columnIndex) Retrieve the given column as ASCII stream from the given ResultSet.
Reader	getClobAsCharacterStream(ResultSet rs, int columnIndex) Retrieve the given column as character stream from the given ResultSet.
String	getClobAsString(ResultSet rs, int columnIndex) Retrieve the given column as String from the given ResultSet.
LobCreator	getLobCreator() Create a new LobCreator instance, i.e.
void	setCreateTemporaryLob(boolean createTemporaryLob) Specify whether to copy a byte array / String into a temporary JDBC Blob / Clob object created through the JDBC 4.0 createBlob / createClob methods.
void	setStreamAsLob(boolean streamAsLob) Specify whether to submit a binary stream / character stream to the JDBC driver as explicit LOB content, using the JDBC 4.0 setBlob / setClob method with a stream argument.
void	setWrapAsLob(boolean wrapAsLob) Specify whether to submit a byte array / String to the JDBC driver wrapped in a JDBC Blob / Clob object, using the JDBC setBlob / setClob method with a Blob / Clob argument.

Methods inherited from class org.springframework.jdbc.support.lob.AbstractLobHandler

getBlobAsBinaryStream, getBlobAsBytes, getClobAsAsciiStream, getClobAsCharacterStream, getClobAsString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logger

protected final Log logger

Constructor Detail

DefaultLobHandler

public DefaultLobHandler()

Method Detail

setWrapAsLob

public void setWrapAsLob(boolean wrapAsLob)

Specify whether to submit a byte array / String to the JDBC driver wrapped in a JDBC Blob / Clob object, using the JDBC setBlob / setClob method with a Blob / Clob argument.

Default is "false", using the common JDBC 2.0 setBinaryStream / setCharacterStream method for setting the content. Switch this to "true" for explicit Blob / Clob wrapping against JDBC drivers that are known to require such wrapping (e.g. PostgreSQL's for access to OID columns, whereas BYTEA columns need to be accessed the standard way).

This setting affects byte array / String arguments as well as stream arguments, unless "streamAsLob" overrides this handling to use JDBC 4.0's new explicit streaming support (if available).

See Also:

PreparedStatement.setBlob(int, java.sql.Blob), PreparedStatement.setClob(int, java.sql.Clob)

setStreamAsLob

public void setStreamAsLob(boolean streamAsLob)

Specify whether to submit a binary stream / character stream to the JDBC driver as explicit LOB content, using the JDBC 4.0 setBlob / setClob method with a stream argument.

Default is "false", using the common JDBC 2.0 setBinaryStream / setCharacterStream method for setting the content. Switch this to "true" for explicit JDBC 4.0 streaming, provided that your JDBC driver actually supports those JDBC 4.0 operations (e.g. Derby's).

This setting affects stream arguments as well as byte array / String arguments, requiring JDBC 4.0 support. For supporting LOB content against JDBC 3.0, check out the "wrapAsLob" setting.

See Also:

PreparedStatement.setBlob(int, java.io.InputStream, long), PreparedStatement.setClob(int, java.io.Reader, long)

setCreateTemporaryLob

public void setCreateTemporaryLob(boolean createTemporaryLob)

Specify whether to copy a byte array / String into a temporary JDBC Blob / Clob object created through the JDBC 4.0 createBlob / createClob methods.

Default is "false", using the common JDBC 2.0 setBinaryStream / setCharacterStream method for setting the content. Switch this to "true" for explicit Blob / Clob creation using JDBC 4.0.

This setting affects stream arguments as well as byte array / String arguments, requiring JDBC 4.0 support. For supporting LOB content against JDBC 3.0, check out the "wrapAsLob" setting.

See Also:

Connection.createBlob(), Connection.createClob()

getBlobAsBytes

public byte[] getBlobAsBytes(ResultSet rs,
                             int columnIndex)
                      throws SQLException

Description copied from interface: LobHandler

Retrieve the given column as bytes from the given ResultSet. Might simply invoke ResultSet.getBytes or work with ResultSet.getBlob, depending on the database and driver.

Parameters:

rs - the ResultSet to retrieve the content from

columnIndex - the column index to use

Returns:

the content as byte array, or null in case of SQL NULL

Throws:

SQLException - if thrown by JDBC methods

See Also:

ResultSet.getBytes(int)

getBlobAsBinaryStream

public InputStream getBlobAsBinaryStream(ResultSet rs,
                                         int columnIndex)
                                  throws SQLException

Description copied from interface: LobHandler

Retrieve the given column as binary stream from the given ResultSet. Might simply invoke ResultSet.getBinaryStream or work with ResultSet.getBlob, depending on the database and driver.

Parameters:

rs - the ResultSet to retrieve the content from

columnIndex - the column index to use

Returns:

the content as binary stream, or null in case of SQL NULL

Throws:

SQLException - if thrown by JDBC methods

See Also:

ResultSet.getBinaryStream(int)

getClobAsString

public String getClobAsString(ResultSet rs,
                              int columnIndex)
                       throws SQLException

Description copied from interface: LobHandler

Retrieve the given column as String from the given ResultSet. Might simply invoke ResultSet.getString or work with ResultSet.getClob, depending on the database and driver.

Parameters:

rs - the ResultSet to retrieve the content from

columnIndex - the column index to use

Returns:

the content as String, or null in case of SQL NULL

Throws:

SQLException - if thrown by JDBC methods

See Also:

ResultSet.getString(int)

getClobAsAsciiStream

public InputStream getClobAsAsciiStream(ResultSet rs,
                                        int columnIndex)
                                 throws SQLException

Description copied from interface: LobHandler

Retrieve the given column as ASCII stream from the given ResultSet. Might simply invoke ResultSet.getAsciiStream or work with ResultSet.getClob, depending on the database and driver.

Parameters:

rs - the ResultSet to retrieve the content from

columnIndex - the column index to use

Returns:

the content as ASCII stream, or null in case of SQL NULL

Throws:

SQLException - if thrown by JDBC methods

See Also:

ResultSet.getAsciiStream(int)

getClobAsCharacterStream

public Reader getClobAsCharacterStream(ResultSet rs,
                                       int columnIndex)
                                throws SQLException

Description copied from interface: LobHandler

Retrieve the given column as character stream from the given ResultSet. Might simply invoke ResultSet.getCharacterStream or work with ResultSet.getClob, depending on the database and driver.

Parameters:

rs - the ResultSet to retrieve the content from

columnIndex - the column index to use

Returns:

the content as character stream

Throws:

SQLException - if thrown by JDBC methods

See Also:

ResultSet.getCharacterStream(int)

getLobCreator

public LobCreator getLobCreator()

Description copied from interface: LobHandler

Create a new LobCreator instance, i.e. a session for creating BLOBs and CLOBs. Needs to be closed after the created LOBs are not needed anymore - typically after statement execution or transaction completion.

Returns:

the new LobCreator instance

See Also:

LobCreator.close()