官网 ：https://mybatis-mp.cn

 1. 单表 +@Fetch 注解 + fetchFilter 方法

 @Data @ResultEntity(SysUser.class) public class SysUserVo { private Integer id; private String userName; private String password; private Integer roleId; private LocalDateTime create_time; @Fetch(source = SysUser.class, property = "roleId", target = SysRole.class, targetProperty = "id") private List<SysRoleVo> sysRoles; }

 List<SysUserVO> list = QueryChain.of(sysUserMapper) .from(SysUser.class) .fetchFilter(SysUserVO::getRoles,where->where.eq(SysRole::getStatus,1)) .returnType(SysUserVO.class) .list();

fetchFilter 方法是对 @Fetch 注解的增强，没有特殊要求一般，可忽略

 

2. 单表查询

 SysUser sysUser = QueryChain.of(sysUserMapper) .eq(SysUser::getId, 1) .eq(SysUser::getUserName,'admin') .get(); 

3.VO 映射

 @Data @ResultEntity(SysUser.class) public class SysUserVo { private Integer id; private String userName; //字段名字不一样时 @ResultEntityField(property = "password") private String pwd; } 

 SysUserVO sysUserVO = QueryChain.of(sysUserMapper) .eq(SysUser::getId, 1) .eq(SysUser::getUserName,'admin') .returnType(SysUserVO.class) .list(); 

4. join 查询

 @Data @ResultEntity(SysUser.class) public class SysUserVo { private Integer id; private String userName; //字段名字不一样时 @ResultEntityField(property = "password") private String pwd; //映射一个对象 1对1 @NestedResultEntity(target = SysRole.class) prviate SysRole sysRole; //映射多个对象 1对多 @NestedResultEntity(target = SysRole.class) prviate List<SysRole> sysRoles; } 

 List<SysUserRoleVO> list = QueryChain.of(sysUserMapper) .from(SysUser.class) .join(SysUser.class, SysRole.class) .returnType(SysUserRoleVO.class) .list(); 

 

 

还有很多很多超级方便有趣的写法，欢迎大家来使用 https://mybatis-mp.cn

例如：

1 . 多表 join A 内嵌 B B 内嵌 C 都可以

2 . 不使用 join 使用 @Fetch 注解 + fetchFilter 方法实现 将 A JOIN B 变成 query A + query B

3 . 使用 @Paging 注解 实现你的 xml 自动分页

4 . 使用 SQL 模板，让你 ORM 更简单更容易扩展，再也不怕被框架限制了