CODEWITHSUNDEEP
javajsonspringhibernate
Sunny
Sunny

Reputation: 147

How to show JSON column name using JPA?

Within my entity class I have 3 Strings along with getters and setters. I am using Jackson to display results. I would like to see column and data like this...

[[id:"1", name:"Tim", address:"street"]]

However, I only get the data back without the column name as below...

[["1","Tom","street"]]

Is there a jackson annotation that would show the column name? Does this have something to do with marshalling/unmarshalling?

Entity

@Entity
@Table(name = "Personnel")
public class User implements Serializable {

private String id;
private String name;
private String address;

public User(String id, String name, String address) 
 {
    this.id = id;
    this.name = name;
    this.address = address;
 }

@Id
@Column(name = "name", unique = true, nullable = false)
public String getName() {
    return this.name;
}....
//setters getters

Impl

@Transactional(readOnly=true)
public List<User> getUsers() throws Exception{
List<User> userList= new ArrayList<User>();
String qry = "select u.id, u.name, u.address from User as u where u.name = 'Tim'" ;
List<String> jsonrows;
Query query = sessionFactory.getCurrentSession().createQuery(qry);  
userList.addAll(query.list());
return userList;

Controller

@RequestMapping(value = "/users/find", method = RequestMethod.GET, produces="application/json")
public List<User> getUserName() {
 List<User> result= null;
    try {  
        { result = service.getUserList();
        }
      } catch (Exception e) {  
          e.printStackTrace();  
      } 
    return result;
}

So I tried to use GSON and then got back numbers for my column names with the code below.

Any ideas?

Upvotes: 4

Views: 3081

Answers (1)

JB Nizet
JB Nizet

Reputation: 691755

First of all, your query doesn't actually return a List<String>. It returns a List<Object[]>, where each array contains 3 elements: the ID, the name and the address.

Since all you have is the values contained in the column, there is no way a JSON serializer can guess that the first element of the array is an ID, the second a name and the third an address.

You would have the JSON you want if, instead of returning a List<Object[]>, your query returned a List<User>. Then, Gson would have objects with named fields, and could transform those Java objects to JSON objects with the same fields.

So your query should simply be

 select u from User u where u.name = 'Tim'

And the method should return the List<User> returned by this query. By the way, this method should be named getUsersNamedTim(), and not getUser(), which implies that the method returns only one user.

Upvotes: 3

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