JdbcTemplate query查询方法

JdbcTemplate 中有很多的查询方法，整理几个比较常用的方法。

1、queryFor*方法很好用，简单强大。

2、query查询方法中带有回调接口有三个：ResultSetExtractor、RowCallbackHandler、RowMapper  使用ResultSetExtractor时，一般是直接new ResultSetExtractor()，然后在extractData(ResultSet rs)方法中实现自己的内容，最后返回Object结果。  使用RowCallbackHandler时，也是new RowCallbackHandler()，然后在processRow(ResultSet rs)方法中实现自己代码，并且将内容保存在上下文变量中，因为此方法没有返回类型（void）  使用RowMapper时，new RowMapper(), 然后在mapRow(ResultSet rs, int rowNum)实现自己代码，并返回Object结果。

3、ResultSetExtractor一次处理多个结果，而RowCallbackHandler、RowMapper只处理单行结果，具体内容可参照下面的代码，代码都是经过测试的，绝对好使。

 @SuppressWarnings("unchecked")
     public static void main(String[] args) {

         try {
             BasicDataSource datasource = new BasicDataSource();
             datasource.setDriverClassName("com.mysql.jdbc.Driver");
             datasource.setUrl("jdbc:mysql://127.0.0.1:3306/xzx");
             datasource.setUsername("root");
             datasource.setPassword("root");

             JdbcTemplate jt = new JdbcTemplate(datasource);

             // query1(jt);
             // query2(jt);
             // query3(jt);
             // query4(jt);
             // query5(jt);
             // query6(jt);
             // query7(jt);
             // query8(jt);
             query9(jt);
         } catch (Exception e) {
             e.printStackTrace();
         }

     }

     @SuppressWarnings("unchecked")
     private static void query9(JdbcTemplate jt) {

         List list1=new ArrayList();

         String sql = "select * from userinfo where id;

         list1=jt.execute(sql,new PreparedStatementCallback() {

             public Object doInPreparedStatement(PreparedStatement ps) throws SQLException, DataAccessException {

                 ps.setInt(1, 20);

                 ResultSet rs=ps.executeQuery();

                 Userinfo userinfo = new Userinfo();

                 List list=new ArrayList();

                 while (rs.next()) {
                     userinfo.setId(rs.getInt("id"));
                     userinfo.setUsername(rs.getString("username"));
                     userinfo.setPassword(rs.getString("password"));
                     userinfo.setCrateDate(rs.getDate("createDate"));
                     list.add(userinfo);
                 }

                 return list;
             }
         });

         System.out.println(list1.size());
     }

     /**
      * queryForInt(String sql)
      *
      * queryFor**(String sql)
      *
      * @param jt
      */

     private static void query8(JdbcTemplate jt) {
         int i = jt.queryForInt("select count(*) from userinfo");
         System.out.println(i);

     }

     /**
      * query(String sql, PreparedStatementSetter pss, ResultSetExtractor rse)
      *
      * query(String sql, PreparedStatementSetter pss, RowCallbackHandler rch)
      *
      * query(String sql, PreparedStatementSetter pss, RowMapper rowMapper)
      *
      * @param jt
      */

     @SuppressWarnings("unchecked")
     private static void query7(JdbcTemplate jt) {
         List list1 = new ArrayList();

         String sql = "select * from userinfo where id;

         list1 = jt.query(sql, new PreparedStatementSetter() {

             public void setValues(PreparedStatement ps) throws SQLException {
                 ps.setInt(1, 20);
                 ps.setString(2, "user4");

             }

         }, new ResultSetExtractor() {

             public Object extractData(ResultSet rs) throws SQLException, DataAccessException {
                 List list = new ArrayList();

                 while (rs.next()) {

                     Userinfo u = new Userinfo();

                     u.setId(rs.getInt("id"));

                     u.setUsername(rs.getString("username"));

                     u.setPassword(rs.getString("password"));

                     u.setCrateDate(rs.getDate("createDate"));

                     list.add(u);

                 }

                 return list;
             }
         });

         System.out.println(list1.size());
     }

     /**
      * query(String sql, Object[] args, ResultSetExtractor rse) query(String
      * sql, Object[] args, int[] argTypes, ResultSetExtractor rse)
      *
      * query(String sql, Object[] args, RowMapper rowMapper) query(String
      * sql, Object[] args, int[] argTypes, RowMapper rowMapper)
      *
      * query(String sql, Object[] args, RowCallbackHandler rch) query(String
      * sql, Object[] args, int[] argTypes, RowCallbackHandler rch)
      *
      * argTypes:java.sql.Type中有定义
      *
      * @param jt
      */

     @SuppressWarnings("unchecked")
     private static void query6(JdbcTemplate jt) {

         List list1 = new ArrayList();

         String sql = "select * from userinfo where id;

         list1 = jt.query(sql, new Object[] { 15, "user4" }, new ResultSetExtractor() {

             public Object extractData(ResultSet rs) throws SQLException, DataAccessException {

                 List list = new ArrayList();

                 while (rs.next()) {

                     Userinfo u = new Userinfo();

                     u.setId(rs.getInt("id"));

                     u.setUsername(rs.getString("username"));

                     u.setPassword(rs.getString("password"));

                     u.setCrateDate(rs.getDate("createDate"));

                     list.add(u);

                 }

                 return list;
             }
         });

         System.out.println(list1.size());

     }

     /**
      * query(final String sql, final ResultSetExtractor rse) query(String
      * sql, RowCallbackHandler rch) query(String sql, RowMapper rowMapper)
      *
      * @param jt
      */

     @SuppressWarnings("unchecked")
     private static void query5(JdbcTemplate jt) {

         List list1 = new ArrayList();

         String sql = "select * from userinfo where id<20";

         list1 = jt.query(sql, new ResultSetExtractor() {

             public Object extractData(ResultSet rs) throws SQLException, DataAccessException {

                 List list = new ArrayList();

                 while (rs.next()) {

                     Userinfo u = new Userinfo();

                     u.setId(rs.getInt("id"));

                     u.setUsername(rs.getString("username"));

                     u.setPassword(rs.getString("password"));

                     u.setCrateDate(rs.getDate("createDate"));

                     list.add(u);

                 }

                 return list;
             }

         });

         System.out.println(((Userinfo) list1.get(4)).getUsername());

     }

     /**
      * query(PreparedStatementCreator psc, RowMapper rowMapper) 多次调用RowMapper
      *
      * @param jt
      */

     static int i = 0;

     static int j = 0;

     static int k = 0;

     @SuppressWarnings("unchecked")
     public static void query4(JdbcTemplate jt) {

         List list1 = new ArrayList();

         list1 = jt.query(new PreparedStatementCreator() {

             public PreparedStatement createPreparedStatement(Connection con) throws SQLException {

                 System.out.println("i=" + (++i));

                 String sql = "select * from userinfo where id;

                 PreparedStatement ps = con.prepareStatement(sql);

                 ps.setInt(1, 20);

                 return ps;
             }
         }, new RowMapper() {

             public Object mapRow(ResultSet rs, int rowNum) throws SQLException {

                 System.out.println("j=" + (++j));

                 Userinfo u = new Userinfo();

                 u.setId(rs.getInt("id"));

                 u.setUsername(rs.getString("username"));

                 u.setPassword(rs.getString("password"));

                 u.setCrateDate(rs.getDate("createDate"));

                 return u;
             }
         });

         System.out.println(list1.size());

     }

     /**
      * query(PreparedStatementCreator psc, RowCallbackHandler rch)
      *
      * @param jt
      */

     @SuppressWarnings("unchecked")
     public static void query3(JdbcTemplate jt) {

         final List list = new ArrayList();

         jt.query(new PreparedStatementCreator() {

             public PreparedStatement createPreparedStatement(Connection con) throws SQLException {

                 System.out.println("i=" + (++i));

                 String sql = "select * from userinfo where id;

                 PreparedStatement ps = con.prepareStatement(sql);

                 ps.setInt(1, 20);

                 return ps;
             }
         }, new RowCallbackHandler() {

             public void processRow(ResultSet rs) throws SQLException {

                 System.out.println("j=" + (++j));
                 while (rs.next()) {

                     Userinfo u = new Userinfo();

                     u.setId(rs.getInt("id"));

                     u.setUsername(rs.getString("username"));

                     u.setPassword(rs.getString("password"));

                     u.setCrateDate(rs.getDate("createDate"));

                     list.add(u);

                 }

             }
         });

         System.out.println(list.size());
     }

     /**
      * query(PreparedStatementCreator psc, ResultSetExtractor rse)
      *
      * @param jt
      */
     @SuppressWarnings("unchecked")
     public static void query2(JdbcTemplate jt) {
         Userinfo u = new Userinfo();
         u = jt.query(new PreparedStatementCreator() {

             public PreparedStatement createPreparedStatement(Connection con) throws SQLException {

                 System.out.println("i=" + (++i));

                 String sql = "select * from userinfo where id=?";

                 PreparedStatement ps = con.prepareStatement(sql);

                 ps.setInt(1, 20000);

                 return ps;
             }
         }, new ResultSetExtractor() {

             public Object extractData(ResultSet rs) throws SQLException, DataAccessException {

                 System.out.println("j=" + (++j));

                 Userinfo userinfo = new Userinfo();

                 while (rs.next()) {

                     userinfo.setId(rs.getInt("id"));

                     userinfo.setUsername(rs.getString("username"));

                     userinfo.setPassword(rs.getString("password"));

                     userinfo.setCrateDate(rs.getDate("createDate"));

                 }

                 return userinfo;
             }
         });
         System.out.println(u.getCrateDate());
     }

     /**
      * query( PreparedStatementCreator psc, final PreparedStatementSetter pss,
      * final ResultSetExtractor rse)
      *
      * @param jt
      */
     @SuppressWarnings("unchecked")
     public static void query1(JdbcTemplate jt) {
         Userinfo u = new Userinfo();

         u = jt.query(new PreparedStatementCreator() {

             public PreparedStatement createPreparedStatement(Connection con) throws SQLException {

                 System.out.println("i=" + (++i));

                 String sql = "select * from userinfo where id=?";

                 return con.prepareStatement(sql);
             }
         }, new PreparedStatementSetter() {

             public void setValues(PreparedStatement ps) throws SQLException {

                 System.out.println("j=" + (++j));

                 ps.setInt(1, 20000);

             }
         }, new ResultSetExtractor() {

             public Object extractData(ResultSet rs) throws SQLException, DataAccessException {

                 System.out.println("k=" + (++k));

                 Userinfo userinfo = new Userinfo();

                 while (rs.next()) {
                     userinfo.setId(rs.getInt("id"));
                     userinfo.setUsername(rs.getString("username"));
                     userinfo.setPassword(rs.getString("password"));
                     userinfo.setCrateDate(rs.getDate("createDate"));

                 }

                 return userinfo;
             }
         });

         System.out.println(u.getCrateDate());
     }