1.查询一个实体类对象

• 根据用户id查询用户信息

User getUserById(@Param("id") int id);

<select id="getUserById" resultType="User">
   select * from t_user where id = #{id}
</select>

2.查询一个list集合

List<User> getUserList();

<select id="getUserList" resultType="User">
   select * from t_user
</select>

3.查询一条为map集合的数据

Map<String, Object> getUserToMap(@Param("id") int id);

<select id="getUserToMap" resultType="map">
   select * from t_user where id = #{id}
</select>

4.查询为map集合的多条数据

List<Map<String, Object>> getAllUserToMap();

<select id="getAllUserToMap" resultType="map">
   select * from t_user
</select>