Question

我有使用Jersey的Glassfish服务器用于webservices。我在身体中发送带有JSON的POST请求，并希望Jackson将其映射到JPA实体。那是NPE出现的时候。

实体：

@Entity
@XmlRootElement
@Table(name = "tracks", schema = "public", catalog = "xtracker")
public class Track {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "track_id", nullable = false, insertable = true, updatable = true)
    private Long trackId;
    @Basic
    @Column(name = "time_start", nullable = true, insertable = true, updatable = true)
    private Timestamp timeStart;
    @Basic
    @Column(name = "time_end", nullable = true, insertable = true, updatable = true)
    private Timestamp timeEnd;
    @OneToMany(mappedBy = "track")
    private List<Jump> jumps = new ArrayList<>();
    @OneToMany(mappedBy = "track", cascade = CascadeType.PERSIST)
    private List<Point> points = new ArrayList<>();
    @ManyToOne
    @JoinColumn(name = "user_id", referencedColumnName = "user_id")
    private User user;
...getters and setters

REST方法：

@POST
@Path("tracks")
@Produces("application/json")
@Consumes(MediaType.APPLICATION_JSON)
@Secured
public void addTrack(Track track) {
    System.out.println("track" + track.getTrackId());
}

异常指向track.getTrackId()

杰克逊正常工作，因为当我尝试使用一个字段（没有ManyToOne关系）映射简单的Test对象时，它是正常的

ApplicationConfig：

@javax.ws.rs.ApplicationPath("api")
public class ApplicationConfig extends Application {
    @Override
    public Set<Class<?>> getClasses() {
        Set<Class<?>> resources = new java.util.HashSet<Class<?>>();
        // following code can be used to customize Jersey 2.0 JSON provider:
        try {
            Class jsonProvider = Class.forName("org.glassfish.jersey.jackson.JacksonFeature");
            // Class jsonProvider = Class.forName("org.glassfish.jersey.moxy.json.MoxyJsonFeature");
            // Class jsonProvider = Class.forName("org.glassfish.jersey.jettison.JettisonFeature");
            resources.add(jsonProvider);
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(getClass().getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        resources.add(SecurityFilter.class);
        addRestResourceClasses(resources);
        return resources;
    }

    /**
     * Do not modify addRestResourceClasses() method.
     * It is automatically re-generated by NetBeans REST support to populate
     * given list with all resources defined in the project.
     */
    private void addRestResourceClasses(Set<Class<?>> resources) {
        resources.add(RestResource.class);
    }

}

更新这是来自客户端的JSON示例（我检查它确实到达了泽西岛）：

{"jumps":[],"points":[{"pointId":0,"speed":0.2}]}

（pointId和speed是Point字段）

更新2： 问题解决了：RequestFilter正在清除http实体主体，而null实体正在到达该方法。谢谢！

使用映射JSON到Jackson / Jersey对象时出现NullPointerException

0 个答案: