org.springframework.jdbc.core

Class RowMapperResultSetExtractor<T>

  • java.lang.Object
    • org.springframework.jdbc.core.RowMapperResultSetExtractor<T>
  • Type Parameters:
    T - the result element type
    All Implemented Interfaces:
    ResultSetExtractor<java.util.List<T>>


    public class RowMapperResultSetExtractor<T>
    extends java.lang.Object
    implements ResultSetExtractor<java.util.List<T>>
    Adapter implementation of the ResultSetExtractor interface that delegates to a RowMapper which is supposed to create an object for each row. Each object is added to the results List of this ResultSetExtractor.

    Useful for the typical case of one object per row in the database table. The number of entries in the results list will match the number of rows.

    Note that a RowMapper object is typically stateless and thus reusable; just the RowMapperResultSetExtractor adapter is stateful.

    A usage example with JdbcTemplate:

    JdbcTemplate jdbcTemplate = new JdbcTemplate(dataSource);  // reusable object
     RowMapper rowMapper = new UserRowMapper();  // reusable object
    
     List allUsers = (List) jdbcTemplate.query(
         "select * from user",
         new RowMapperResultSetExtractor(rowMapper, 10));
    
     User user = (User) jdbcTemplate.queryForObject(
         "select * from user where id=?", new Object[] {id},
         new RowMapperResultSetExtractor(rowMapper, 1));

    Alternatively, consider subclassing MappingSqlQuery from the jdbc.object package: Instead of working with separate JdbcTemplate and RowMapper objects, you can have executable query objects (containing row-mapping logic) there.

    Since:
    1.0.2
    Author:
    Juergen Hoeller
    See Also:
    RowMapper, JdbcTemplate, MappingSqlQuery
    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method and Description
      java.util.List<T> extractData(java.sql.ResultSet rs)
      Implementations must implement this method to process the entire ResultSet.
      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
    • Constructor Detail

      • RowMapperResultSetExtractor

        public RowMapperResultSetExtractor(RowMapper<T> rowMapper)
        Create a new RowMapperResultSetExtractor.
        Parameters:
        rowMapper - the RowMapper which creates an object for each row
      • RowMapperResultSetExtractor

        public RowMapperResultSetExtractor(RowMapper<T> rowMapper,
                                           int rowsExpected)
        Create a new RowMapperResultSetExtractor.
        Parameters:
        rowMapper - the RowMapper which creates an object for each row
        rowsExpected - the number of expected rows (just used for optimized collection handling)
    • Method Detail

      • extractData

        public java.util.List<T> extractData(java.sql.ResultSet rs)
                                      throws java.sql.SQLException
        Description copied from interface: ResultSetExtractor
        Implementations must implement this method to process the entire ResultSet.
        Specified by:
        extractData in interface ResultSetExtractor<java.util.List<T>>
        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)