A generic ResultSetExtractor to be used with Spring's JdbcTemplate for any simple beans.

GenericResultSetExtractor.java

import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.function.BiConsumer;
import java.util.function.Supplier;

import org.springframework.dao.DataAccessException;
import org.springframework.jdbc.core.JdbcTemplate;
import org.springframework.jdbc.core.ResultSetExtractor;

/**
 * Result set extractor to be used with Spring's
 * {@link JdbcTemplate#query(String, ResultSetExtractor)} and other methods that
 * uses a {@link ResultSetExtractor}.
 * 
 * This result set extractor can be used with any simple bean of given generic
 * instant <T>.
 * 
 * @author kannan.r
 *
 * @param <T>
 */
public class GenericResultSetExtractor<T> implements ResultSetExtractor<List<T>>
{

    private Map<String, BiConsumer<T, String>> itsBeanToSetterMap;

    private Supplier<T> itsSupplier;

    /**
     * Instantiates the {@link GenericResultSetExtractor}
     * 
     * @param theBeanToSetterMap
     *            The bean to setter map, with the keys as column names in upper
     *            case and the values as the {@link BiConsumer} instances that
     *            sets attribute for the respective column
     * @param theInstanceSupplier
     *            The {@link Supplier} that creates the bean of the specific
     *            type.
     */
    public GenericResultSetExtractor(Map<String, BiConsumer<T, String>> theBeanToSetterMap,
            Supplier<T> theInstanceSupplier)
    {
        itsBeanToSetterMap = theBeanToSetterMap;
        itsSupplier = theInstanceSupplier;
    }

    @Override
    public List<T> extractData(ResultSet theRs) throws SQLException, DataAccessException
    {
        List<T> aResultList = new ArrayList<>();

        while (theRs.next())
        {

            T anInstance = itsSupplier.get();

            int aColCount = theRs.getMetaData().getColumnCount();

            for (int anIndex = 1; anIndex <= aColCount; anIndex++)
            {
                String aCol = theRs.getMetaData().getColumnLabel(anIndex);
                BiConsumer<T, String> aSetterMethod = itsBeanToSetterMap.get(aCol.toUpperCase());
                aSetterMethod.accept(anInstance, theRs.getString(aCol));
            }

            aResultList.add(anInstance);
        }
        return aResultList;
    }

    /**
     * Test user class for demo purpose.
     *
     * Class intended just for demo. Not part of the {@link ResultSetExtractor}
     */
    public static class User
    {
        private int id;
        private String name;

        public int getId()
        {
            return id;
        }

        public void setId(int id)
        {
            this.id = id;
        }

        public String getName()
        {
            return name;
        }

        public void setName(String name)
        {
            this.name = name;
        }
    }

    /**
     * Method intended just for demo. Not part of the {@link ResultSetExtractor}
     */
    public void demoUsage(JdbcTemplate aTemplate)
    {
        Map<String, BiConsumer<User, String>> aUserColumnToSetterMap = new HashMap<>();

        aUserColumnToSetterMap.put("ID", (User u, String id) -> {
            u.setId(Integer.parseInt(id));
        });
        aUserColumnToSetterMap.put("NAME", (User u, String name) -> {
            u.setName(name);
        });

        GenericResultSetExtractor<User> anExtractor = new GenericResultSetExtractor<User>(
                aUserColumnToSetterMap, () -> new User());

        List<User> query = aTemplate
                .query("SELECT ID, NAME FROM USERS WHERE USER.DEPT_ID='something'", anExtractor);

    }
}