mybatis-plus.md

基本配置

• spring boot 添加依赖

  <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.1.2</version>
  </dependency>

• 定义mapper接口

public interface UserMapper extends BaseMapper<User> { }

• 使用

@Autowired
    UserMapper userMapper;

    @Test
    public void test(){
        User user = new User();
        user.setUsername("root");
        user.setPassword("123");
        user.setAge(15);
        user.setCreateTime(LocalDate.now());
        assertEquals(1,userMapper.insert(user));
    }

查询

• 普通查询

• 条件构造器查询

  @Test
    public void test2(){
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.like("username","roo")
                .lt("age",50);
        var list = userMapper.selectList(queryWrapper);
        assertEquals(2,list.size());
        assertEquals("root",list.get(0).getUsername());
        assertEquals("rood",list.get(1).getUsername());
    }

自定义SQL

• 注解

  public interface UserMapper extends BaseMapper<User> {
  
    @Select("SELECT * FROM user ")
    List<User> selectAll();
  }

• xml 同mybatis

• 分页查询

  • 配置分页插件

    @Bean
    public PaginationInterceptor paginationInterceptor(){
        return new PaginationInterceptor();
    }

  • 查询

    @Test
    public void test4(){
        Page<User> page = new Page<>(1,2);
    
        var list = userMapper.selectPage(page,null).getRecords();
        assertEquals(2,list.size());
    
    }

更新

@Test
public void test5(){
    UpdateWrapper<User> wrapper = new UpdateWrapper<User>().eq("username","root");
    User user = new User();
    user.setPassword("5678");
    userMapper.update(user, wrapper);
}

删除

UpdateWrapper<User> wrapper = new UpdateWrapper<User>()
    .eq("username","root");
userMapper.delete(wrapper);

AR模式

• 实体类继承Model

@Data
public class User extends Model<User> {

    private String username;

    private String password;

    private Integer age;

    private LocalDate createTime;
}

@Test
    public void test6(){
        User user = new User();
        user.setUsername("20190716");
        user.setPassword("123");
        user.setCreateTime(LocalDate.now());
        user.setAge(111);
        assertTrue(user.insert());
    }

主键策略

• 设置策略

@TableId(type = IdType.UUID)
private String username;

User user = new User();
user.setPassword("1111");
assertTrue(user.insert());

通过Service