Spring Restcontroller not returning xml

Question

I'm getting json response from my controller even though I added the xml annotations to my model. I get the list of users in json with no problems. Can I use @Entity and @XmlRootElement in the same class?

User.java

@Entity
@Table(name = "usr")
@XmlRootElement
public class User {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID", nullable = false, unique = true, length = 11)
    private int id;

    @Column(nullable = false)
    private String username;

    @Column(nullable = false)
    private String password;

    @Column(nullable = false)
    private String firstName;

    @Column(nullable = false)
    private String lastName;

    @Column(nullable = false)
    private String email;

    @OneToMany(mappedBy = "user")
    private List<Post> post;

    @OneToMany(mappedBy = "user")
    private List<Friend> friends;

    public List<Friend> getFriends() {
        return friends;
    }

    public void setFriends(List<Friend> friends) {
        this.friends = friends;
    }

    public List<Post> getPost() {
        return post;
    }

    public void setPost(List<Post> post) {
        this.post = post;
    }

    public int getId() {
        return id;
    }


    public void setId(int id) {
        this.id = id;
    }

    @XmlElement
    public String getUsername() {
        return username;
    }


    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }


    public void setPassword(String password) {
        this.password = password;
    }

    @XmlElement
    public String getFirstName() {
        return firstName;
    }


    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    @XmlElement
    public String getLastName() {
        return lastName;
    }


    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    @XmlElement
    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

}

getAllUsers

 @Override
    public List<User> getAllUsers() {
        List<User> users = new ArrayList<User>();
        Session session = HibernateUtil.getSessionAnnotationFactory().openSession();
        Transaction trns = null;
        try {
            trns = session.beginTransaction();
            users = session.createQuery("select firstName, lastName, email, username as name from User").list();
            trns.commit();
        } catch (RuntimeException e) {
            if (trns != null) {
                trns.rollback();
            }
            e.printStackTrace();
        } finally {
            session.flush();
            session.close();
        }
        return users;
    }

and in the controller

@RequestMapping(value="/api/users", method = RequestMethod.GET)
public List<User> getAllUsers() {

//List<User> users = new ArrayList<User>();
UserDao userdao = new UserDaoImpl();
List<User> users = userdao.getAllUsers();


return users;

 }

What am I missing here?

Answer 1

There is a nice blog entry from Spring about this. From there is this about content negotiation:

Enabling Content Negotiation in Spring MVC

Spring supports a couple of conventions for selecting the format required: URL suffixes and/or a URL parameter. These work alongside the use of Accept headers. As a result, the content-type can be requested in any of three ways. By default they are checked in this order:

• Add a path extension (suffix) in the URL. So, if the incoming URL is something like http://myserver/myapp/accounts/list.html then HTML is required. For a spreadsheet the URL should be http://myserver/myapp/accounts/list.xls . The suffix to media-type mapping is automatically defined via the JavaBeans Activation Framework or JAF (so activation.jar must be on the class path).
• A URL parameter like this: http://myserver/myapp/accounts/list?format=xls . The name of the parameter is format by default, but this may be changed. Using a parameter is disabled by default, but when enabled, it is checked second.
• Finally the Accept HTTP header property is checked. This is how HTTP is actually defined to work, but, as previously mentioned, it can be problematic to use.

But if you just want to fix the return type I'd add the annotation @RequestMapping(value="/api/users", produces={"application/xml"}) to your controller method.

Answer 2

First, try to change

@RequestMapping(value="/api/users", method = RequestMethod.GET)

to

@ResponseBody
@RequestMapping(value="/api/users", method = RequestMethod.GET, produces = MediaType.APPLICATION_XML_VALUE)

Second, check out if client code ( I assume it is javascript ) is sending correct accept-type, because Jackson - the default serialization engine would derive format of response body from HTTP header.

Third, ensure that you have JAXB present in your classpath.