org.springframework.jdbc.support.lob

Class 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, 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 
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method and Description
      java.io.InputStream getBlobAsBinaryStream(java.sql.ResultSet rs, int columnIndex)
      Retrieve the given column as binary stream from the given ResultSet.
      byte[] getBlobAsBytes(java.sql.ResultSet rs, int columnIndex)
      Retrieve the given column as bytes from the given ResultSet.
      java.io.InputStream getClobAsAsciiStream(java.sql.ResultSet rs, int columnIndex)
      Retrieve the given column as ASCII stream from the given ResultSet.
      java.io.Reader getClobAsCharacterStream(java.sql.ResultSet rs, int columnIndex)
      Retrieve the given column as character stream from the given ResultSet.
      java.lang.String getClobAsString(java.sql.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 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

        @Nullable
        public byte[] getBlobAsBytes(java.sql.ResultSet rs,
                                               int columnIndex)
                                        throws java.sql.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:
        java.sql.SQLException - if thrown by JDBC methods
        See Also:
        ResultSet.getBytes(int)
      • getBlobAsBinaryStream

        @Nullable
        public java.io.InputStream getBlobAsBinaryStream(java.sql.ResultSet rs,
                                                                   int columnIndex)
                                                            throws java.sql.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:
        java.sql.SQLException - if thrown by JDBC methods
        See Also:
        ResultSet.getBinaryStream(int)
      • getClobAsString

        @Nullable
        public java.lang.String getClobAsString(java.sql.ResultSet rs,
                                                          int columnIndex)
                                                   throws java.sql.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:
        java.sql.SQLException - if thrown by JDBC methods
        See Also:
        ResultSet.getString(int)
      • getClobAsAsciiStream

        public java.io.InputStream getClobAsAsciiStream(java.sql.ResultSet rs,
                                                        int columnIndex)
                                                 throws java.sql.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:
        java.sql.SQLException - if thrown by JDBC methods
        See Also:
        ResultSet.getAsciiStream(int)
      • getClobAsCharacterStream

        public java.io.Reader getClobAsCharacterStream(java.sql.ResultSet rs,
                                                       int columnIndex)
                                                throws java.sql.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:
        java.sql.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()