org.springframework.jdbc.core

Interface ResultSetExtractor<T>

  • Type Parameters:
    T - the result type
    All Known Implementing Classes:
    AbstractLobStreamingResultSetExtractor, RowMapperResultSetExtractor, SqlRowSetResultSetExtractor
    Functional Interface:
    This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.


    @FunctionalInterface
    public interface ResultSetExtractor<T>
    Callback interface used by JdbcTemplate's query methods. Implementations of this interface perform the actual work of extracting results from a ResultSet, but don't need to worry about exception handling. SQLExceptions will be caught and handled by the calling JdbcTemplate.

    This interface is mainly used within the JDBC framework itself. A RowMapper is usually a simpler choice for ResultSet processing, mapping one result object per row instead of one result object for the entire ResultSet.

    Note: In contrast to a RowCallbackHandler, a ResultSetExtractor object is typically stateless and thus reusable, as long as it doesn't access stateful resources (such as output streams when streaming LOB contents) or keep result state within the object.

    Since:
    April 24, 2003
    Author:
    Rod Johnson, Juergen Hoeller
    See Also:
    JdbcTemplate, RowCallbackHandler, RowMapper, AbstractLobStreamingResultSetExtractor
    • Method Detail

      • extractData

        @Nullable
        T extractData(java.sql.ResultSet rs)
                         throws java.sql.SQLException,
                                DataAccessException
        Implementations must implement this method to process the entire ResultSet.
        Parameters:
        rs - the 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:
        java.sql.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