Java 将Bean注入Servlet
我想在servlet中注入bean。但每次我尝试时都会出现这个错误Java 将Bean注入Servlet,java,servlets,jpa,Java,Servlets,Jpa,我想在servlet中注入bean。但每次我尝试时都会出现这个错误 javax.servlet.ServletException: Error instantiating servlet class servlet.RegisterServlet 我猜某些注释丢失或错误。那我该怎么做呢?是否有其他方法将beant注入servlet RegisterServlet public class RegisterServlet extends HttpServlet { @EJB pr
javax.servlet.ServletException: Error instantiating servlet class servlet.RegisterServlet
我猜某些注释丢失或错误。那我该怎么做呢?是否有其他方法将beant注入servlet
RegisterServlet
public class RegisterServlet extends HttpServlet {
@EJB
protected KorisniciFacade kf;
public RegisterServlet() {
// stuff
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//more stuff
}
private boolean invalidUser(String username) {
// stuff
}
}
FacadeLocal
@Local
public interface KorisniciFacadeLocal {
void create(Korisnici korisnici);
void edit(Korisnici korisnici);
void remove(Korisnici korisnici);
Korisnici find(Object id);
List<Korisnici> findAll();
List<Korisnici> findRange(int[] range);
int count();
}
@Local
公共接口KorisniciFacadeLocal{
无效创建(Korisnici Korisnici);
无效编辑(Korisnici-Korisnici);
无效删除(Korisnici Korisnici);
Korisnici查找(对象id);
列出findAll();
列表findRange(int[]范围);
int count();
}
正面
@Stateless
public class KorisniciFacade extends AbstractFacade<Korisnici> implements KorisniciFacadeLocal {
@PersistenceContext(unitName = "MobMelPU")
private EntityManager em;
@Override
protected EntityManager getEntityManager() {
return em;
}
public KorisniciFacade() {
super(Korisnici.class);
}
}
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();
}
}
@无状态
公共类KorisniciFacade扩展了AbstractFacade,实现了KorisniciFacadeLocal{
@PersistenceContext(unitName=“MobMelPU”)
私人实体管理者;
@凌驾
受保护的EntityManager getEntityManager(){
返回em;
}
公共KorisniciFacade(){
超级(Korisnici.class);
}
}
AbstractFacade
@Stateless
public class KorisniciFacade extends AbstractFacade<Korisnici> implements KorisniciFacadeLocal {
@PersistenceContext(unitName = "MobMelPU")
private EntityManager em;
@Override
protected EntityManager getEntityManager() {
return em;
}
public KorisniciFacade() {
super(Korisnici.class);
}
}
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();
}
}
公共抽象类AbstractFacade{
私有类实体类;
公共抽象外观(类entityClass){
this.entityClass=entityClass;
}
受保护的抽象EntityManager getEntityManager();
公共无效创建(T实体){
getEntityManager().persist(实体);
}
公共无效编辑(T实体){
getEntityManager().merge(实体);
}
公共无效删除(T实体){
getEntityManager().remove(getEntityManager().merge(entity));
}
公共找不到(对象id){
返回getEntityManager().find(entityClass,id);
}
公共列表findAll(){
javax.persistence.CriteriaQuery cq=getEntityManager().getCriteriaBuilder().createQuery();
cq.select(cq.from(entityClass));
返回getEntityManager().createQuery(cq.getResultList();
}
公共列表findRange(int[]范围){
javax.persistence.CriteriaQuery cq=getEntityManager().getCriteriaBuilder().createQuery();
cq.select(cq.from(entityClass));
javax.persistence.Query q=getEntityManager().createQuery(cq);
q、 setMaxResults(范围[1]-范围[0]+1);
q、 setFirstResult(范围[0]);
返回q.getResultList();
}
公共整数计数(){
javax.persistence.CriteriaQuery cq=getEntityManager().getCriteriaBuilder().createQuery();
javax.persistence.criteria.Root rt=cq.from(entityClass);
选择(getEntityManager().getCriteriaBuilder().count(rt));
javax.persistence.Query q=getEntityManager().createQuery(cq);
返回((长)q.getSingleResult()).intValue();
}
}
您的键入错误。您应该使用此处的界面:
@EJB
protected KorisniciFacade kf;
正确答案:
@EJB
protected KorisniciFacadeLocal kf;
堆栈跟踪的内容不止这些。全部发布。Thx有效。但现在我有第二个问题。我把它添加到了主题问题-一个主题中。如果你还有任何问题,就换一个话题。