mybatis中的动态sql应用

使用mybatis提供的动态sql可简化我们模糊查询时向sql追加各种条件，追加条件特别容易出错

dao接口:

List<User> selectAllUsersByCondition();

dao实现类:

@Override
    public List<User> selectAllUsersByCondition() {
        SqlSession sqlSession=null;
        List<User> userList = null;
        Map<String,String> map =new HashMap<String,String>();
        map.put("uname", "奔");
        try {
            userList = MyBatisUtils.getSqlSesion("mybatis/mybatis.xml").selectList("edu.aeon.mybatis.entity.UserMapper.selectAllUsersByCondition",map);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return userList;
    }

User.Mapper.xml:

<select id="selectAllUsersByCondition" parameterType="Map" resultType="User">
 select uid,uname,upw from user
 <where>
     <if test="#{uname} !=null">
     uname like concat('%',#{uname},'%')
     </if>
 </where>
 </select>

测试类:

public static void selectAllUsersByCondition(){
        UserDao userDao =new UserDaoImpl();
        List<User> userList = userDao.selectAllUsersByCondition();
        for(User user:userList){
            System.out.println(user);
        }
    }

测试结果: