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Je fais un service REST en utilisant Hibernate et Struts dans NetBeans où j'ai créé le service RESTful en utilisant Jersey JAX-RS RI 2.5.1 et JAX RS 2.0 et j'ai une erreur comme suit:NullPointerException dans le service REST
type Exception report
un message java.lang.NullPointerException
Description Le serveur a rencontré une erreur interne qui l'a empêché de remplir cette demande.
exception
javax.servlet.ServletException: java.lang.NullPointerException
org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:392)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:382)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:345)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:220)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
root cause
java.lang.NullPointerException
com.myapp.struts.service.AbstractFacade.findAll(AbstractFacade.java:41)
com.myapp.struts.service.UserTblFacadeREST.findAll(UserTblFacadeREST.java:66)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
java.lang.reflect.Method.invoke(Method.java:498)
org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory$1.invoke(ResourceMethodInvocationHandlerFactory.java:81)
org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:151)
org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:171)
org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$TypeOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:195)
org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:104)
org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:402)
org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:349)
org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:106)
org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:259)
org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
org.glassfish.jersey.internal.Errors.process(Errors.java:315)
org.glassfish.jersey.internal.Errors.process(Errors.java:297)
org.glassfish.jersey.internal.Errors.process(Errors.java:267)
org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:318)
org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:236)
org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1010)
org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:373)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:382)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:345)
org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:220)
org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
et mon code est:
/*
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package com.myapp.struts.service;
import com.myapp.struts.UserTbl;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import javax.ws.rs.Consumes;
import javax.ws.rs.DELETE;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
/**
*
* @author Vihaan
*/
@javax.ejb.Stateless
@Path("usertbl")
public class UserTblFacadeREST extends AbstractFacade<UserTbl> {
@PersistenceContext(unitName = "reststrutsPU")
private EntityManager em;
public UserTblFacadeREST() {
super(UserTbl.class);
}
@POST
@Override
@Consumes({"application/xml", "application/json"})
public void create(UserTbl entity) {
super.create(entity);
}
@PUT
@Path("{id}")
@Consumes({"application/xml", "application/json"})
public void edit(@PathParam("id") Integer id, UserTbl entity) {
super.edit(entity);
}
@DELETE
@Path("{id}")
public void remove(@PathParam("id") Integer id) {
super.remove(super.find(id));
}
@GET
@Path("{id}")
@Produces({"application/xml", "application/json"})
public UserTbl find(@PathParam("id") Integer id) {
return super.find(id);
}
@GET
@Override
@Produces({"application/xml", "application/json"})
public List<UserTbl> findAll() {
return super.findAll();
}
@GET
@Path("{from}/{to}")
@Produces({"application/xml", "application/json"})
public List<UserTbl> findRange(@PathParam("from") Integer from, @PathParam("to") Integer to) {
return super.findRange(new int[]{from, to});
}
@GET
@Path("count")
@Produces("text/plain")
public String countREST() {
return String.valueOf(super.count());
}
@Override
protected EntityManager getEntityManager() {
return em;
}
}
UserTbl.java
/*
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* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package com.myapp.struts;
import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.xml.bind.annotation.XmlRootElement;
/**
*
* @author Vihaan
*/
@Entity
@Table(name = "user_tbl")
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "UserTbl.findAll", query = "SELECT u FROM UserTbl u"),
@NamedQuery(name = "UserTbl.findById", query = "SELECT u FROM UserTbl u WHERE u.id = :id"),
@NamedQuery(name = "UserTbl.findByUsername", query = "SELECT u FROM UserTbl u WHERE u.username = :username"),
@NamedQuery(name = "UserTbl.findByPassword", query = "SELECT u FROM UserTbl u WHERE u.password = :password"),
@NamedQuery(name = "UserTbl.findByName", query = "SELECT u FROM UserTbl u WHERE u.name = :name")})
public class UserTbl implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "ID")
private Integer id;
@Basic(optional = false)
@Column(name = "username")
private String username;
@Basic(optional = false)
@Column(name = "password")
private String password;
@Basic(optional = false)
@Column(name = "name")
private String name;
public UserTbl() {
}
public UserTbl(Integer id) {
this.id = id;
}
public UserTbl(Integer id, String username, String password, String name) {
this.id = id;
this.username = username;
this.password = password;
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
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;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@Override
public int hashCode() {
int hash = 0;
hash += (id != null ? id.hashCode() : 0);
return hash;
}
@Override
public boolean equals(Object object) {
// TODO: Warning - this method won't work in the case the id fields are not set
if (!(object instanceof UserTbl)) {
return false;
}
UserTbl other = (UserTbl) object;
if ((this.id == null && other.id != null) || (this.id != null && !this.id.equals(other.id))) {
return false;
}
return true;
}
@Override
public String toString() {
return "com.myapp.struts.UserTbl[ id=" + id + " ]";
}
}
c'est la classe AbstractFacade
/*
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* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package com.myapp.struts.service;
import java.util.List;
import javax.persistence.EntityManager;
/**
*
* @author Vihaan
*/
public abstract class AbstractFacade<T> {
private Class<T> entityClass;
public AbstractFacade(Class<T> entityClass) {
this.entityClass = entityClass;
}
protected abstract EntityManager getEntityManager();
public void create(T entity) {
getEntityManager().persist(entity);
}
public void edit(T entity) {
getEntityManager().merge(entity);
}
public void remove(T entity) {
getEntityManager().remove(getEntityManager().merge(entity));
}
public T find(Object id) {
return getEntityManager().find(entityClass, id);
}
public List<T> findAll() {
javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
cq.select(cq.from(entityClass));
return getEntityManager().createQuery(cq).getResultList();
}
public List<T> findRange(int[] range) {
javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
cq.select(cq.from(entityClass));
javax.persistence.Query q = getEntityManager().createQuery(cq);
q.setMaxResults(range[1] - range[0] + 1);
q.setFirstResult(range[0]);
return q.getResultList();
}
public int count() {
javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
javax.persistence.criteria.Root<T> rt = cq.from(entityClass);
cq.select(getEntityManager().getCriteriaBuilder().count(rt));
javax.persistence.Query q = getEntityManager().createQuery(cq);
return ((Long) q.getSingleResult()).intValue();
}
}
Il semble que NPE est jeté à l'intérieur du code AbstractFacade. Cela nous donnerait plus de visibilité si vous ajoutez son code source. –
Est-ce que "em" est instancié lorsque vous appelez "findAll"? –
J'ai ajouté la classe AbstractFacade –