org.springframework.jdbc.support.lob.DefaultLobHandler

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 链接如下：

http://static.springsource.org/spring/docs/2.5.x/api/org/springframework/jdbc/support/lob/DefaultLobHandler.html

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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

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public class DefaultLobHandlerextends AbstractLobHandler

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

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, and only to a limited degree to Oracle 10g! As a consequence, use OracleLobHandler for accessing Oracle BLOBs/CLOBs.

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.

See the LobHandler javadoc for a summary of recommendations.

Since:

04.12.2003

Author:

Juergen Hoeller

See Also:

setStreamAsLob(boolean), 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)

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Nested Class Summary

protected  class	DefaultLobHandler.DefaultLobCreator           Default LobCreator implementation as inner class.

 

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Field Summary

protected  Log	logger

 

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Constructor Summary

DefaultLobHandler()

 

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Method Summary

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. a session for creating BLOBs and CLOBs.
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.

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

getBlobAsBinaryStream, getBlobAsBytes, getClobAsAsciiStream, getClobAsCharacterStream, getClobAsString

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Methods inherited from class java.lang.Object

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

 

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Field Detail

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logger

protected final Log logger

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Constructor Detail

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DefaultLobHandler

public DefaultLobHandler()

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Method Detail

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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).

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)

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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 usage, 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)

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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)

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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)

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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)

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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)

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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)

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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()