【Spring】JdbcTemplate常用方法使用示例

---

update

update方法一般用来进行增删改.
常用的几个方法如下:

    //update(String sql) ==> int
        String sql = "update t_score set chiese = 95 where id =1";
        int n = template.update(sql);


        //update(String sql, Object... args) ==> int
        String sql2 = "update t_score set chiese = ? where id = ?";
        int n2 = template.update(sql2, 95, 1);


        //update(String,Object[] args, int[] argTypes) ==> int
        String sql3 = "update t_score set chinese = ? , math = ? where id = ? ";
        Object[] args = new Object[]{55, 80, 2};
        int[] argTypes = new int[]{Types.INTEGER, Types.INTEGER, Types.INTEGER}; // java.sql.Types
        int n3 = template.update(sql3, args, argTypes);

query

query方法主要用来查询, 在JdbcTemplate中常用的查询方法有个queryForMap、queryForObject、queryForRowSet、queryForList. 使用示例如下:

queryForMap

       //queryForMap(String sql) ==> Map<String, Object>
        Map<String, Object> score_map = template.queryForMap("select * from t_score where id=1");
        System.out.println(score_map);//{id=1, sid=20181515114, chinese=54, math=54, english=96}


        //queryForMap(String sql,Object... args);
        Map<String, Object> score_map2 = template.queryForMap("select * from t_score where id=?", 1);
        System.out.println(score_map2);//{id=1, sid=20181515114, chinese=54, math=54, english=96}


        //queryForMap(String sql ,Object[] args,int[] argTypes) ==> Map<String, Object>
        Object[] args = new Object[]{1};
        int[] argsType = new int[]{Types.INTEGER};
        Map<String, Object> score_map3 = template.queryForMap("select * from t_score where id=?", args, argsType);
        System.out.println(score_map3);//{id=1, sid=20181515114, chinese=54, math=54, english=96}

queryForObject

        //queryForObject(String sql,class<T> requireType); ==> T
        int total = template.queryForObject("select (chinese+math+english) as total from t_score where id=1",Integer.class);
        System.out.println(total);//204


        //queryForObject(String sql,Object[] args,class<T> requireType); ==> T
        Object[] args = new Object[]{1};
        Integer total = template.queryForObject("select (chinese+math+english) as total from t_score where id=?", args, Integer.class);
        System.out.println(total);//204


        //queryForObject(String sql, Object[] args,int[] argTypes, class<T> requireType); ==> T
        Object[] args = new Object[]{1};
        int[] argTypes = new int[]{Types.INTEGER};
        int total = template.queryForObject("select (chinese+math+english) as total from t_score where id=?", args, argTypes, Integer.class);
        System.out.println(total);//204

queryForRowSet

       //queryForRowSet(String sql); ==> SqlRowSet == ResultSet
        SqlRowSet sqlRowSet = template.queryForRowSet("select * from t_score");
        //sqlRowSet == ResultSet
        if(sqlRowSet.isFirst())sqlRowSet.previous();
        while (sqlRowSet.next()){
            System.out.println("id:"+sqlRowSet.getInt(1));
            //todo
        }


//         使用方式同上
        template.queryForRowSet(String sql, Object...args);
        template.queryForRowSet(String sql,Object[] args,int[] argTypes);

queryForList

        //queryForList(String sql);  ==> List<Map<String, Object>>
        String sql = "select * from t_score";
        List<Map<String, Object>> scoreMaps = template.queryForList(sql);
        scoreMaps.forEach(System.out::println);
        //输出
        {id=1, sid=20181515114, chinese=54, math=54, english=96}
        {id=2, sid=20181515101, chinese=55, math=80, english=99}
        {id=3, sid=20181515102, chinese=98, math=88, english=79}
        {id=4, sid=20181515105, chinese=80, math=80, english=78}
        {id=7, sid=20181515103, chinese=50, math=20, english=88}


        //queryForList(String sql, class<T> elementType); ==> List<T>
        List<Integer> total_score_list = template.queryForList("select (chinese+math+english) as total from t_score", Integer.class);
        for(Integer i:total_score_list) System.out.println(i);
        // 输出
        204
        234
        265
        238
        158


        //queryForList(String sql,Object... args)  ==>  List<Map<String, Object>>
        List<Map<String, Object>> maps = template.queryForList("select * from t_score where english>=?", 80);
        for (Map<String, Object> m : maps) System.out.println(m);
        //输出
        {id=1, sid=20181515114, chinese=54, math=54, english=96}
        {id=2, sid=20181515101, chinese=55, math=80, english=99}
        {id=7, sid=20181515103, chinese=50, math=20, english=88}


        //queryForList(String sql,Object[] args,int[] argTypes) => List<Map<String, Object>>
        Object[] args = new Object[]{80};
        int[] argTypes = new int[]{Types.INTEGER};
        List<Map<String, Object>> maps = template.queryForList("select * from t_score where english>=?", args, argTypes);
        for (Map<String, Object> m : maps) System.out.println(m);
        //输出
        {id=1, sid=20181515114, chinese=54, math=54, english=96}
        {id=2, sid=20181515101, chinese=55, math=80, english=99}
        {id=7, sid=20181515103, chinese=50, math=20, english=88}


        //queryForList(String sql,Object[] args,int[] argTypes, class<T> elementType )  ==> List<T>
        Object[] args = new Object[]{80};
        int[] argTypes = new int[]{Types.INTEGER};
        List<Integer> integers = template.queryForList("select (chinese + math + english) as total from t_score where english >= ?", args, argTypes, Integer.class);
        for (Integer i : integers) System.out.println(i);
        //输出
        204
        234
        158

Q&A 请指正!