Class AbstractLobStreamingResultSetExtractor<T>
- java.lang.Object
- org.springframework.jdbc.core.support.AbstractLobStreamingResultSetExtractor<T>
- All Implemented Interfaces:
ResultSetExtractor<T>
public abstract class AbstractLobStreamingResultSetExtractor<T> extends Object implements ResultSetExtractor<T>
Abstract ResultSetExtractor implementation that assumes streaming of LOB data. Typically used as inner class, with access to surrounding method arguments.Delegates to the
streamData
template method for streaming LOB content to some OutputStream, typically using a LobHandler. Converts an IOException thrown during streaming to a LobRetrievalFailureException.A usage example with JdbcTemplate:
JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource); // reusable object final LobHandler lobHandler = new DefaultLobHandler(); // reusable object jdbcTemplate.query( "SELECT content FROM imagedb WHERE image_name=?", new Object[] {name}, new AbstractLobStreamingResultSetExtractor() { public void streamData(ResultSet rs) throws SQLException, IOException { FileCopyUtils.copy(lobHandler.getBlobAsBinaryStream(rs, 1), contentStream); } } );
- Since:
- 1.0.2
- Author:
- Juergen Hoeller
- See Also:
LobHandler
,LobRetrievalFailureException
Constructor Summary
Constructors Constructor Description AbstractLobStreamingResultSetExtractor()
Method Summary
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description T
extractData(ResultSet rs)
Delegates to handleNoRowFound, handleMultipleRowsFound and streamData, according to the ResultSet state.protected void
handleMultipleRowsFound()
Handle the case where the ResultSet contains multiple rows.protected void
handleNoRowFound()
Handle the case where the ResultSet does not contain a row.protected abstract void
streamData(ResultSet rs)
Stream LOB content from the given ResultSet to some OutputStream.
Constructor Detail
AbstractLobStreamingResultSetExtractor
public AbstractLobStreamingResultSetExtractor()
Method Detail
extractData
public final T extractData(ResultSet rs) throws SQLException, DataAccessException
Delegates to handleNoRowFound, handleMultipleRowsFound and streamData, according to the ResultSet state. Converts an IOException thrown by streamData to a LobRetrievalFailureException.- Specified by:
extractData
in interfaceResultSetExtractor<T>
- Parameters:
rs
- ResultSet to extract data from. Implementations should not close this: it will be closed by the calling JdbcTemplate.- Returns:
- an arbitrary result object, or
null
if none (the extractor will typically be stateful in the latter case). - Throws:
SQLException
- if a SQLException is encountered getting column values or navigating (that is, there's no need to catch SQLException)DataAccessException
- in case of custom exceptions- See Also:
handleNoRowFound()
,handleMultipleRowsFound()
,streamData(java.sql.ResultSet)
,LobRetrievalFailureException
handleNoRowFound
protected void handleNoRowFound() throws DataAccessException
Handle the case where the ResultSet does not contain a row.- Throws:
DataAccessException
- a corresponding exception, by default an EmptyResultDataAccessException- See Also:
EmptyResultDataAccessException
handleMultipleRowsFound
protected void handleMultipleRowsFound() throws DataAccessException
Handle the case where the ResultSet contains multiple rows.- Throws:
DataAccessException
- a corresponding exception, by default an IncorrectResultSizeDataAccessException- See Also:
IncorrectResultSizeDataAccessException
streamData
protected abstract void streamData(ResultSet rs) throws SQLException, IOException, DataAccessException
Stream LOB content from the given ResultSet to some OutputStream.Typically used as inner class, with access to surrounding method arguments and to a LobHandler instance variable of the surrounding class.
- Parameters:
rs
- the ResultSet to take the LOB content from- Throws:
SQLException
- if thrown by JDBC methodsIOException
- if thrown by stream access methodsDataAccessException
- in case of custom exceptions- See Also:
LobHandler.getBlobAsBinaryStream(java.sql.ResultSet, java.lang.String)
,FileCopyUtils