Jersey et fichier JSON : multiplication d'objets

Bonjour,

J'ai un souci avec jersey.
Ma méthode lui envoie une liste d'object.

Code:

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@Path("/get")
public class Ressource {
 
    @GET
    @Path("/projects")
    @Produces("application/json")
    public List<Project> getProjects() {
        List<Project> list = DaoFactory.getProjectDao().listProjectsInProgress();
        return list;
 
    }
}

J'ai fait un test avec une liste ne comportant qu'un seul objet et il me r'envoie un fichier json avec plusieurs fois le même objet.

Code:

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[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":[{"id":45,"title":"gd","description":"fdgfgd","dateStart":1387407600000,"dateEnd":1388358000000,"goal":2006,"category":{"id":10,"name":"Defaut","projects":

etc...

C'est quoi le problème ?

On peut voir le contenu de la classe project?

A priori, je dirais une référence cyclique, mais je peux me tromper...

Voici mon objet project :

Code:

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@Entity
public class Project implements Serializable {
 
    private static final long serialVersionUID = 1L;
    @Id
    @GeneratedValue
    private long id;
 
    private String title;
    private String description;
    @Temporal(javax.persistence.TemporalType.DATE)
    private Date dateStart;
    @Temporal(javax.persistence.TemporalType.DATE)
    private Date dateEnd;
    private int goal;
 
    private boolean Expired;
    private boolean Complete;
 
    @ManyToOne
    @JoinColumn(name = "category_fk")
    private Category category;
 
    @ManyToOne
    @JoinColumn(name = "user_fk")
    private User user;
 
    @OneToMany(mappedBy = "project")
    private List<Donation> donations = new ArrayList<Donation>();

Quand j'appel ma méthode qui la charge de ma base tout va bien je n'ai qu'un seul objet.
Mais ça ne fonctionne pas avec le json.

C'est bien un problème de référence cyclique...

Dans la classe project, tu as une référence vers une catégorie qui contient elle-même une liste de projets. Quand le sérialiseur json passe en revue les propriétés, et comme tu ne lui as donné aucune instruction, il tombe dans une espèce de boucle sans fin de sérialisation (je sérialise un projet -> une catégorie -> qui contient une liste de projet -> je sérialise la liste de projets -> le premier contient une catégorie -> qui contient une liste de projets -> le premier projet contient une catégorie -> ..........)

Plusieurs solutions, plus ou moins couteuses:

1) le plus simple, mais pas le mieux: mettre un javax.xml.bind.annotation.XmlTransient sur la propriété "private Category category;", ce qui va la supprimer du flux json et du coup, éviter les références cycliques
2) (mieux) créer une classe dédiée pour représenter le flux json correctement, puis faire un mapping d'une forme à l'autre (peut-être via un outil comme dozer). ça pourrait ressembler à ça:
Code:

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 @XmlRootElement @JsonIgnoreProperties(ignoreUnknown = true) public class ProjectJson { @XmlElement(name = "id") private long id; @XmlElement(name = "title") private String title; @XmlElement(name = "desc") private String description; @XmlElement(name = "dateStart") private Date dateStart; @XmlElement(name = "dateEnd") private Date dateEnd; @XmlElement(name = "expired") private boolean Expired; @XmlElement(name = "complete") private boolean Complete; @XmlElement(name = "categoryName") private String category; ... }
C'est mieux bien qu'un peu plus complexe. De toute façon, la solution d'exposer les entités de base de données directement en json (comme tu l'as fait) est assez mauvaise (aucun contrôle sur ce qui sort et service web très dépendant de la représentation en DB). Une couche de transformation se justifie dans ces cas-là.

:)

Bonjour,

Pourriez-vous montrer le code du test?

Dans certains cas de figure il pourrait être utile d'annoter les getters susceptibles à générer des références cycliques (ceux qui ramènent des listes d'objets) tant par @XmlTransient que par @JsonIgnore.