Mybatis-plus 入门笔记（二）分页、更新、ActiveRecord

淡淡的烟草味﹌ 2023-06-18 15:57 18阅读 0赞

1、更新操作

@RunWith(SpringRunner.class)
    @SpringBootTest
    public class UpdateMapperTest {
    
        @Resource
        private UserMapper userMapper;
    
        @Test
        public void test01() {
            User user = userMapper.selectById("1141529133436698625");
            user.setName("孙燕姿123");
            userMapper.updateById(user);
        }
    
        @Test
        public void updateByWrapper() {
            User whereUser = new User();
            whereUser.setName("李艺伟");
    
            UpdateWrapper<User> userUpdateWrapper = new UpdateWrapper<>(whereUser);
            userUpdateWrapper.like("name","李艺伟").eq("age",28);
            User user = new User();
            user.setEmail("lyw2019@baomidou.com");
            user.setAge(29);
            int rows = userMapper.update(user, userUpdateWrapper);
            System.out.println("影响记录数： " + rows);
        }
    
    
        /**
         * 如果不想传user对象
         */
        @Test
        public void updateByWrapper1() {
            UpdateWrapper<User> userUpdateWrapper = new UpdateWrapper<>();
            userUpdateWrapper.like("name","李艺伟").eq("age",29)
                    .set("email","lyw2020@baomidou.com").set("age", 30);
            int rows = userMapper.update(null, userUpdateWrapper);
            System.out.println("影响记录数： " + rows);
        }
    
        /**
         * 使用LambdaUpdateWrapper
         */
        @Test
        public void lambdaUpdate() {
    
            LambdaUpdateWrapper<User> updateWrapper = Wrappers.<User>lambdaUpdate();
            updateWrapper.eq(User::getName, "李艺伟").eq(User::getAge, 30)
                    .set(User::getEmail, "1234@qq.com").set(User::getAge, 31);
    
            int rows = userMapper.update(null, updateWrapper);
            System.out.println("影响记录数： " + rows);
        }
    
        /**
         * 使用LambdaUpdateChainWrapper
         */
        @Test
        public void lambdaUpdate1() {
            boolean update = new LambdaUpdateChainWrapper<User>(userMapper).eq(User::getName, "李艺伟").eq(User::getAge, 30)
                    .set(User::getAge, 31).update();
    
            System.out.println("更新成功： " + update);
        }
    }

2、分页操作

@RunWith(SpringRunner.class)
    @SpringBootTest
    public class UserMapperPageTest {
    
        @Resource
        private UserMapper userMapper;
    
        @Test
        public void testPage1() {
            QueryWrapper<User> queryWrapper = Wrappers.<User>query();
            queryWrapper.between("age", 20 , 40).isNotNull("email");
    
            // isSearchCount 是否查询总条数
    //        Page<User> page = new Page(2,2,false);
            Page<User> page = new Page(2,2,true);
            IPage<User> userIPage = userMapper.selectPage(page, queryWrapper);
            System.out.println("总计页数：" + userIPage.getPages());
            System.out.println("总条数：" + userIPage.getTotal());
    
            List<User> userList = userIPage.getRecords();
            userList.forEach(System.out::println);
        }
    
        @Test
        public void testPage2() {
            QueryWrapper<User> queryWrapper = Wrappers.<User>query();
            queryWrapper.between("age", 20 , 40).isNotNull("email");
    
            Page<User> page = new Page(2,2,true);
            IPage<Map<String, Object>> userIPage = userMapper.selectMapsPage(page, queryWrapper);
            System.out.println("总计页数：" + userIPage.getPages());
            System.out.println("总条数：" + userIPage.getTotal());
    
            List<Map<String, Object>> userList = userIPage.getRecords();
            userList.forEach(System.out::println);
        }
    
        /**
         * 自定义分页
         */
        @Test
        public void testPage3() {
            QueryWrapper<User> queryWrapper = Wrappers.<User>query();
            queryWrapper.between("age", 20 , 40).isNotNull("email");
    
            Page<User> page = new Page(2,2,true);
            IPage<User> userIPage = userMapper.selectUserPage(page, queryWrapper);
            System.out.println("总计页数：" + userIPage.getPages());
            System.out.println("总条数：" + userIPage.getTotal());
    
            List<User> userList = userIPage.getRecords();
            userList.forEach(System.out::println);
        }
    
    }

3、Activerecord

实体类只需继承 Model 类即可实现基本 CRUD 操作，简单来说就是一个实体类继承Model类，并通过注解与数据库的表名进行关联，这样就可以通过实体类直接进行表的简单增删改查操作，这样也确实极大的方便了开发人员。

@Data
    @TableName("User")
    @EqualsAndHashCode(callSuper = false)
    public class User extends Model<User> {
    
        private static final long serialVersionUID = 1L;
    
        /**
         * 局部策略配置id生成策略
         */
        @TableId(value = "id"/*, type = IdType.AUTO*/)
        private Long id;
    
        @TableField("name")
        private String name;
    
        @TableField("age")
        private Integer age;
    
        /**
         * 邮箱
         */
        @TableField("email")
        private String email;
    
        /**
         * 上级id
         */
        private Long managerId;
    
        /**
         * 创建时间
         */
        private LocalDateTime createTime;
    
    }

测试代码

@RunWith(SpringRunner.class)
    @SpringBootTest
    public class ActiveRecordTest {
    
        @Test
        public void tst() {
            User user = new User();
            user.setName("刘华");
            user.setAge(29);
            user.setEmail("lh@baomidou.com");
            user.setManagerId(1087982257332887553L);
            user.setCreateTime(LocalDateTime.now());
            boolean insert = user.insert();
            System.out.println("===insert===" + insert);
        }
    
        /**
         * 查询时user和userSelect不是同一个值
         */
        @Test
        public void update() {
            User user = new User();
            user.setId(1088248166370832385L);
            User userSelect = user.selectById();
            System.out.println(userSelect == user);
            System.out.println(userSelect);
        }
    }