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xbatis 一款非常好用 ORM 框架，它是如何多表 join 查询的？

日期：2025-02-19点击：31收藏

联表查询

内联查询

java

 public class Demo {  @Autowired  private SysUserMapper sysUserMapper;  public void page() {  Pager<SysUser> pager= QueryChain.of(sysUserMapper)  .join(SysUser::getRoleId, SysRole::getId)  .like(SysUser::getUserName,"abc")  .paging(Pager.of(1));  } }

左联查询

左联查询适合1对1情况，如果不是，则分页时需要关闭框架优化：Pager.of(1).setOptimize(false)

java

 public class Demo {  @Autowired  private SysUserMapper sysUserMapper;  public void page() {  Pager<SysUser> pager= QueryChain.of(sysUserMapper)  .leftJoin(SSysUser::getRoleId, SysRole::getId)  .like(SysUser::getUserName,"abc")  .paging(Pager.of(1));  } }

右联查询

java

 public class Demo {  @Autowired  private SysUserMapper sysUserMapper;  public void page() {  Pager<SysUser> pager= QueryChain.of(sysUserMapper)  .join(JoinMode.RIGHT, SysUser::getRoleId, SysRole::getId)  .like(SysUser::getUserName,"abc")  .paging(Pager.of(1));  } }

全连接查询

java

 public class Demo {  @Autowired  private SysUserMapper sysUserMapper;  public void page() {  Pager<SysUser> pager= QueryChain.of(sysUserMapper)  .join(JoinMode.FULL, SysUser::getRoleId, SysRole::getId)  .like(SysUser::getUserName,"abc")  .paging(Pager.of(1));  } }