how to print an alias attribute in JSP file using #Query annotation - spring-data-jpa

Question

This is rows in database.
group userid
1 a
2 b
1 c
3 d
I want to query using #query annotation about
#Query(value ="SELECT *, count(*) as cnt FROM user group by body order by cnt DESC", nativeQuery = true)
List<User> getGroupRanking();
and, i expect to result about
group cnt
1 2
2 1
3 d
but List<User> collection is not accept to 'cnt' attribute which was alias.
another reason not to accept, User defined class was not containing 'cnt' attribute. i was defined 'cnt' attribute in User Class like following code.
public class User{
#Column(name ="group")
private String group;
..
private Integer cnt;
public Integer getCnt(){ return cnt; }
public void setCnt(Integer cnt){ this.cnt = cnt; }
}
Although I will prevent to update the schema, The above code update the schema. because
appConfig.xml configuration was set like this
<prop key="hibernate.hbm2ddl.auto">update</prop>
i don't want to update schema, and i want to display cnt attribute in JSP file through User Class(bean) when i using #Query annotation. how to accept a 'cnt' attribute using the User class without update schema?
'as' keyword usage not containing in detail(link)

Answer 1

It's difficult to understand what you need, but I'll try... ))
First create a projection:
public interface UserCount {
User getUser();
long getUserCount();
}
Then create a repository query method which return this projection:
public interface UserRepo extends JpaRepository<User, Long> {
#Query("select u as user, count(u) as userCount from User u group by u order by userCount desc")
List<UserCount> getUserCounts();
}
Then you can get list of UserCount projections and send it to your JSP view.
Additional reading:
Projections on repository query methods
Data transfer object
UPDATE
Controller:
#Controller
public class UserController {
#Autoware
private UserRepo repo;
#GetMapping("/")
public String withCount(Model model) {
List<UserCount> userCounts = getUserCounts();
model.addAttribute("userCounts", userCounts);
return "userCounts";
}
}
JSP
<table>
...
<c:forEach items="${userCounts}" var="item">
<tr>
<td>${item.user.group}</td>
...
<td>${item.userCount}</td>
</tr>
</c:forEach>
</table>
Some info: 1, 2
I recommend to switch from jsp to thymeleaf.