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, 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

    All Methods Instance Methods Concrete Methods
    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

          @Nullable
          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

          @Nullable
          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

          @Nullable
          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()`