weekendCriteria usage of the generic mapper

https://www.cnblogs.com/grey-wolf/p/8435723.html；

Weekend <the User> Weekend = new new Weekend <> (the User. Class );
         // keyword query part of the 
        String keyword = pageReq.getKeyword (); 
        WeekendCriteria <the User, Object> keywordCriteria = weekend.weekendCriteria ();
         IF (StringUtils.isNotEmpty (keyword)) { 
            keywordCriteria.orLike (the User ::, getUserName, keyword) .orLike (the User :: getPoliceNo, keyword) .orLike (the User :: getRealName, keyword); 
　　　　　　  // here not necessary to use the one below it, otherwise, the above combination of conditions will repeat
             // weekend.and (keywordCriteria) 
        }
         // sector query part 
        Example Example = new new Example (the User.class);
        Example.Criteria criteria = example.createCriteria();
        criteria.andEqualTo("departmentId", departmentId);
        weekend.and(criteria);

        PageHelper.startPage(pageReq.getPageIndex(), pageReq.getPageSize());
        List<User> users = userMapper.selectByExample(weekend);

相当于
WHERE (
  user_name = ? 
  OR police_no = ? 
  OR real_name = ?
) 
AND (department_id = ?)