Get Join Table Data using Hibernate - spring

Question

I have two tables and trying to get data with inner join using hibernate with spring.
And i will get json using ModelMapper and get duplicate record also.
So, please suggest me how to get unique record with inner join query using hibernate.
I have Two Tables:
Table Name: User
---------------------
id | email
---------------------
1 | m#gmail.com
2 | e#gmail.com
---------------------
Table Name: Userrole
----------------------------------------
roleid | userid | rolename
----------------------------------------
1 | 1 | Admin
2 | 1 | HR
3 | 2 | Employee
4 | 2 | Executive
----------------------------------------
#Entity
#Table(name="user")
public class User{
#Id
#GeneratedValue
private int id;
#Column
private String email;
#OneToMany
private List<Userrole> userroles;
public void setId(int id){
this.id = id;
}
public void setEmail(String email){
this.email= email;
}
public int getId(){
return id;
}
public String getEmail(){
return email;
}
public List<Userrole> getUserrole(){
return userroles;
}
}
#Entity
#Table(name="userrole")
public classs Userrole{
#Id
#GeneratorValue
private int roleid;
#Column
private String rolename;
#ManyToOne
private User user;
// setter and getter
}
public List<User> findAall(){
// Type casting will throw an error
// This will throw error
return (List<User>)session.getCurrentSession().createQuery("from User u join u.userroles");
// this will return List<Object[]>
return session.getCurrentSession().createQuery("from User u join u.userroles");
// So i want to convert to this DTO using ModelMapper object
}
public class UserDTO{
private int id;
private String email;
private List<Userrole> roleusers;
// setter and getter
}
public class UserroleDTO{
private int roleid;
private String rolename;
//settter and getter
}
public interface UserDao{
public List<User> findAll();
}
#Repository
public class UserDaoImpl implements UserDao{
#Override
public List<User> findAll(){
// This will throw an error: ClassCastException
return (List<User>)session.getCurrentSession().createQuery("from User u join u.userroles");
// This will work perfectly and return List<Object[]>
return session.getCurrentSession().createQuery("from User u join u.userroles");
}
}
#Controller
public class HomeController{
#Autowired
private UserDao doa;
ModelMapper modelMapper = new ModelMapper();
#RequestMapping(value="/list")
public List<User> findAll(){
List<User> list = dao.findAll();
List<UserDTO> dto = list.stream().map(user -> convertToDto(user)).collect(Collectors.toList());
return dto;
// This will return
[
{
"id":1,
"email":"m#gmail.com",
"userroles":[
{
"roleid":1,
"rolename":"Admin"
},
{
"roleid":2,
"rolename":"HR"
}
]
},
{
"id":1,
"email":"m#gmail.com",
"userroles":[
{
"roleid":1,
"rolename":"Admin"
},
{
"roleid":2,
"rolename":"HR"
}
]
},
{
"id":2,
"email":"e#gmail.com",
"userroles":[
{
"roleid":3,
"rolename":"Employee"
},
{
"roleid":4,
"rolename":"Executive"
}
]
},
{
"id":2,
"email":"e#gmail.com",
"userroles":[
{
"roleid":3,
"rolename":"Employee"
},
{
"roleid":4,
"rolename":"Executive"
}
]
}
]
// It should return
[
{
"id":1,
"email":"m#gmail.com",
"userroles":[
{
"roleid":1,
"rolename":"Admin"
},
{
"roleid":2,
"rolename":"HR"
}
]
},
{
"id":2,
"email":"e#gmail.com",
"userroles":[
{
"roleid":3,
"rolename":"Employee"
},
{
"roleid":4,
"rolename":"Executive"
}
]
}
]
}
public UserDTO convertToDto(User user){
UserDTO dto = modelMapper.map(user,UserDTO.class);
return dto;
}
}