Mybatis-缓存

MyBatis缓存

（1）一级缓存

1.查询两次相同的数据

测试：

    @Test
    public void test(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);
        
        User user = mapper.getUserById(2);
        System.out.println(user);
        System.out.println("===============================");
        User user2=mapper.getUserById(2);
        System.out.println(user2);

        sqlSession.close();
    }
}

日志分析：

2.缓存失效的情况

增删改操作可能会改变原理啊的数据，所以增删改之后会刷新数据

3.手动清理缓存

@Test
    public void test(){
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        User user = mapper.getUserById(2);
        System.out.println(user);

        sqlSession.clearCache();//手动清理缓存

        User user2=mapper.getUserById(2);
        System.out.println(user2);

        sqlSession.close();
    }