mybatis-plus之自定义sql、分页、Wrapper

自定义sql也想使用Wrapper构建？那这时候就要如下使用，先看定义好的部分常量：

这里只挑三个说明一下：

ew.customSqlSegment   对应条件构造器里的条件      

ew.sqlSet   update是所设置的列      

ew.sqlSelect   query时所选的列      

@Select("SELECT u.* FROM USER u LEFT JOIN `role-user` ru ON u.id=ru.user_id LEFT JOIN role r ON r.id=ru.role_id ${ew.customSqlSegment}")
List<User> findFreash(@Param(Constants.WRAPPER)Wrapper wrapper);
@Select("select ${ew.sqlSelect} from user ${ew.customSqlSegment} ")
List<User> testSqlSelect(@Param(Constants.WRAPPER)Wrapper wrapper);
@Update("update `role-user` set ${ew.sqlSet} ${ew.customSqlSegment}")
int testSqlSet(@Param(Constants.WRAPPER)Wrapper wrapper);      

主要是多对多的一个简单的角色表对应模型，相应的使用例子

userDao.findFreash(Wrappers.query().gt("u.age",19).eq("r.id",1)).forEach(System.out::println);
        userDao.testSqlSelect(Wrappers.query().select("name","age").like("email","qq")).forEach(System.out::println);
userDao.testSqlSet(Wrappers.update().set("set role_id ",2).eq("user_id",1));      

select u.* from user u left join `role-user` ru on u.id=ru.user_id left join role r on r.id=ru.role_id where u.age > ? and r.id = ?
 
select name,age from user where email like ?
 
update `role-user` set role_id =? where user_id = ?      

@Select("SELECT * FROM USER u LEFT JOIN `role-user` ru ON u.id=ru.user_id LEFT JOIN role r ON r.id=ru.role_id ${ew.customSqlSegment}")
    List<Map<String,Object>> findAll(@Param(Constants.WRAPPER)Wrapper wrapper);      

@Select("SELECT * FROM USER u LEFT JOIN `role-user` ru ON u.id=ru.user_id LEFT JOIN role r ON r.id=ru.role_id ${ew.customSqlSegment}")
    List<Map<String,Object>> findWithPage(IPage page,@Param(Constants.WRAPPER)Wrapper wrapper);