org.springframework.jdbc.support.lob.LobHandler |
Known Indirect Subclasses |
Abstraction for handling large binary fields and large text fields in
specific databases, no matter if represented as simple types or Large OBjects.
Its main purpose is to isolate Oracle's peculiar handling of LOBs in
OracleLobHandler
; most other databases should be able to work
with the provided DefaultLobHandler
.
Provides accessor methods for BLOBs and CLOBs, and acts as factory for LobCreator instances, to be used as sessions for creating BLOBs or CLOBs. LobCreators are typically instantiated for each statement execution or for each transaction; they are not thread-safe because they might track allocated database resources in order to free them after execution.
Most databases/drivers should be able to work with DefaultLobHandler
,
which by default delegates to JDBC's direct accessor methods, avoiding the
java.sql.Blob
and java.sql.Clob
API completely.
DefaultLobHandler
can also be configured to access LOBs using
PreparedStatement.setBlob/setClob
(e.g. for PostgreSQL), through
setting the "wrapAsLob"
property.
Unfortunately, Oracle 9i just accepts Blob/Clob instances created via its own
proprietary BLOB/CLOB API, and additionally doesn't accept large streams for
PreparedStatement's corresponding setter methods. Therefore, you need to use
OracleLobHandler
there, which uses Oracle's BLOB/CLOB API for both types
of access. The Oracle 10g JDBC driver should basically work with
DefaultLobHandler
as well, with some limitations in terms of LOB sizes.
Of course, you need to declare different field types for each database. In Oracle, any binary content needs to go into a BLOB, and all character content beyond 4000 bytes needs to go into a CLOB. In MySQL, there is no notion of a CLOB type but rather a LONGTEXT type that behaves like a VARCHAR. For complete portability, use a LobHandler for fields that might typically require LOBs on some database because of the field size (take Oracle's numbers as a guideline).
Summarizing the recommended options (for actual LOB fields):
DefaultLobHandler
with streamAsLob=true
.
DefaultLobHandler
with wrapAsLob=true
.
OracleLobHandler
with a connection-pool-specific
NativeJdbcExtractor
.
DefaultLobHandler
.
Public Methods | |||||||||||
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Retrieve the given column as binary stream from the given ResultSet.
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Retrieve the given column as binary stream from the given ResultSet.
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Retrieve the given column as bytes from the given ResultSet.
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Retrieve the given column as bytes from the given ResultSet.
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Retrieve the given column as ASCII stream from the given ResultSet.
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Retrieve the given column as ASCII stream from the given ResultSet.
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Retrieve the given column as character stream from the given ResultSet.
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Retrieve the given column as character stream from the given ResultSet.
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Retrieve the given column as String from the given ResultSet.
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Retrieve the given column as String from the given ResultSet.
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Create a new
LobCreator instance, i.e. |
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnIndex | the column index to use |
null
in case of SQL NULLSQLException | if thrown by JDBC methods |
---|
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnName | the column name to use |
null
in case of SQL NULLSQLException | if thrown by JDBC methods |
---|
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnIndex | the column index to use |
null
in case of SQL NULLSQLException | if thrown by JDBC methods |
---|
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnName | the column name to use |
null
in case of SQL NULLSQLException | if thrown by JDBC methods |
---|
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnIndex | the column index to use |
null
in case of SQL NULLSQLException | if thrown by JDBC methods |
---|
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnName | the column name to use |
null
in case of SQL NULLSQLException | if thrown by JDBC methods |
---|
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnName | the column name to use |
SQLException | if thrown by JDBC methods |
---|
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnIndex | the column index to use |
SQLException | if thrown by JDBC methods |
---|
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnIndex | the column index to use |
null
in case of SQL NULLSQLException | if thrown by JDBC methods |
---|
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.
rs | the ResultSet to retrieve the content from |
---|---|
columnName | the column name to use |
null
in case of SQL NULLSQLException | if thrown by JDBC methods |
---|
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.