【MyBatis】学习笔记07：模糊查询

• 写法1：$
• 写法2：concat拼接
• 写法3：#（推荐使用）

写法1：$

    /**
     * 根据用户名模糊查询
     * @param username 用户名的关键字
     * @return  List 用户列表
     */
    List getUserByLike(@Param("username") String username);

    
         select * from t_users where userName like "%${username}%"
    

    @Test
    public void testGetUserByLike(){
        SqlSession sqlSession = SqlSessionUtils.getSqlSession();
        SQLMapper mapper = sqlSession.getMapper(SQLMapper.class);
        List list = mapper.getUserByLike("三");
        System.out.println(list);
    }

[User{userId='5',userName='张三'userCount='mllt@xrilang.com',userPassword='123'userGrade='0',userRegDate='null'userBlance='0'}, User{userId='6',userName='李三'userCount='xirlang@mllt.c',userPassword='124'userGrade='0',userRegDate='null'userBlance='0'}]

写法2：concat拼接

    
         
        select * from t_users where userName like concat("%",#{username},"%")
    

[User{userId='5',userName='张三'userCount='mllt@xrilang.com',userPassword='123'userGrade='0',userRegDate='null'userBlance='0'}, User{userId='6',userName='李三'userCount='xirlang@mllt.c',userPassword='124'userGrade='0',userRegDate='null'userBlance='0'}]

写法3：#（推荐使用）

    
         
         
        select * from t_users where userName like "%"#{username}"%"

[User{userId='5',userName='张三'userCount='mllt@xrilang.com',userPassword='123'userGrade='0',userRegDate='null'userBlance='0'}, User{userId='6',userName='李三'userCount='xirlang@mllt.c',userPassword='124'userGrade='0',userRegDate='null'userBlance='0'}]