Question

嗨，所以我的标题中所述的删除方法有问题，出现错误的是javax.ejb.EJBException。有一个堆栈跟踪，组件树和范围变量选项卡，但有很多内容不确定我是否应该在这里发布它们？如果是这样，我会说。对不起，我不能隔离问题我认为如果可以的话我可以解决它，所以我会包括我认为相关的类。我尽力尽我所能地问这个问题。感谢

好的，我的index.xhtml文件中有

    <h:link value="add new cd" outcome="add"></h:link>
    <h:form>
        <h:dataTable var="p" value="#{cdController.findAll()}" border="1" cellpadding="2">
        <h:column>
            <f:facet name="header">ID</f:facet>
            <h:outputText value="#{p.id}"></h:outputText>
        </h:column>
        <h:column>
            <f:facet name="header">Artist</f:facet>
            <h:outputText value="#{p.artist}"></h:outputText>
        </h:column>
        <h:column>
            <f:facet name="header">Duration</f:facet>
            <h:outputText value="#{p.duration}"></h:outputText>
        </h:column>
         <h:column>
            <f:facet name="header">Title</f:facet>
            <h:outputText value="#{p.title}"></h:outputText>
        </h:column>    
         <h:column>
            <f:facet name="header">Option</f:facet>
            <h:commandLink value="Delete" action="#{cdController.delete(c)}"></h:commandLink>
        </h:column> 
    </h:dataTable>
    </h:form>

在我的控制器课程中，我有

package controller;

import entity.Cd;
import javax.inject.Named;
import javax.enterprise.context.SessionScoped;
import java.io.Serializable;
import java.time.Clock;
import java.util.AbstractCollection.*;
import java.util.List;
import javax.ejb.EJB;
import model.CdFacade;

/**
 *
 * @author Mick
 */
@Named(value = "cdController")
@SessionScoped
public class CdController implements Serializable {

    @EJB
    private CdFacade cdFacade;
    private Cd c = new Cd();

    public Cd getC() {
        return c;
    }

    public void setC(Cd c) {
        this.c = c;
    }

    public String add()
    {
        this.cdFacade.create(this.c);
        return "index";
    }
        public void delete(Cd c)
    {
        this.cdFacade.remove(c);
    }
    public CdController() {
    }
     public List<Cd> findAll()
     {
        return this.cdFacade.findAll();
     }

}

好的，在我的add.xhtml（工作正常）我有这个

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://xmlns.jcp.org/jsf/html"
      xmlns:f="http://xmlns.jcp.org/jsf/core">
    <h:head>
        <title>Add CDs</title>
    </h:head>
    <h:body>
        <f:view>


            <h:form>
                <h1><h:outputText value="Create/Edit"/></h1>
                <h:panelGrid columns="2">
                    <h:outputLabel value="Id:" for="id" />
                    <h:inputText id="id" value="#{cdController.c.id}" title="Id" />
                    <h:outputLabel value="Artist:" for="artist" />
                    <h:inputText id="artist" value="#{cdController.c.artist}" title="Artist" />
                    <h:outputLabel value="Duration:" for="duration" />
                    <h:inputText id="duration" value="#{cdController.c.duration}" title="Duration" />
                    <h:outputLabel value="Title:" for="title" />
                    <h:inputText id="title" value="#{cdController.c.title}" title="Title" />

                    <h:commandButton value="save" action="#{cdController.add()}"></h:commandButton>
                </h:panelGrid>
            </h:form>
        </f:view>

    </h:body>
</html>

Cd.java

package entity;

import java.io.Serializable;
import javax.persistence.Basic;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.Table;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;

/**
 *
 * @author Mick
 */
@Entity
@Table(name = "CD")
@XmlRootElement
@NamedQueries({
    @NamedQuery(name = "Cd.findAll", query = "SELECT c FROM Cd c"),
    @NamedQuery(name = "Cd.findById", query = "SELECT c FROM Cd c WHERE c.id = :id"),
    @NamedQuery(name = "Cd.findByArtist", query = "SELECT c FROM Cd c WHERE c.artist = :artist"),
    @NamedQuery(name = "Cd.findByDuration", query = "SELECT c FROM Cd c WHERE c.duration = :duration"),
    @NamedQuery(name = "Cd.findByTitle", query = "SELECT c FROM Cd c WHERE c.title = :title")})
public class Cd implements Serializable {

    private static final long serialVersionUID = 1L;
    @Id
    @Basic(optional = false)
    @NotNull
    @Column(name = "ID")
    private Long id;
    @Size(max = 255)
    @Column(name = "ARTIST")
    private String artist;
    @Size(max = 255)
    @Column(name = "DURATION")
    private String duration;
    @Size(max = 255)
    @Column(name = "TITLE")
    private String title;

    public Cd() {
    }

    public Cd(Long id) {
        this.id = id;
    }

    public Long getId() {
        return id;
    }

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

    public String getArtist() {
        return artist;
    }

    public void setArtist(String artist) {
        this.artist = artist;
    }

    public String getDuration() {
        return duration;
    }

    public void setDuration(String duration) {
        this.duration = duration;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    @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 Cd)) {
            return false;
        }
        Cd other = (Cd) 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 "entity.Cd[ id=" + id + " ]";
    }

}

CdFacade

package model;

import entity.Cd;
import javax.ejb.Stateless;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;

/**
 *
 * @author Mick
 */
@Stateless
public class CdFacade extends AbstractFacade<Cd> {

    @PersistenceContext(unitName = "CD-ejbPU")
    private EntityManager em;

    @Override
    protected EntityManager getEntityManager() {
        return em;
    }

    public CdFacade() {
        super(Cd.class);
    }

}

AbstractFacade

package model;

import java.util.List;
import javax.persistence.EntityManager;

/**
 *
 * @author Mick
 */
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();
    }

}

NetBeans中的CRUD企业应用程序使用EJB，JPA和JSF删除方法抛出错误

0 个答案: