我在使用j7ee ejb 3.1和jpa 2.1在数据库中插入记录的简单测试应用程序实例化servlet类时遇到了问题。我是ejb和jpa的新手，我试图测试一个解决方案。 我使用的是NetBeans 8.0。 我为实体类和ejb分隔了层。
我有com.tsc.deo.entities中的实体类Doctor.java（DEO是应用程序的名称）：
package com.tsc.deo.entities;
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.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import javax.xml.bind.annotation.XmlRootElement;
/**
*
* @author IK
*/
@Entity
@Table(name = "doctor")
@XmlRootElement
@NamedQueries({
@NamedQuery(name = "Doctor.findAll", query = "SELECT d FROM Doctor d"),
@NamedQuery(name = "Doctor.findByIDDoctor", query = "SELECT d FROM Doctor d WHERE d.iDDoctor = :iDDoctor"),
@NamedQuery(name = "Doctor.findBySirname", query = "SELECT d FROM Doctor d WHERE d.sirname = :sirname"),
@NamedQuery(name = "Doctor.findByName", query = "SELECT d FROM Doctor d WHERE d.name = :name"),
@NamedQuery(name = "Doctor.findByPatientIDPatient", query = "SELECT d FROM Doctor d WHERE d.patientIDPatient = :patientIDPatient")})
public class Doctor implements Serializable {
private static final long serialVersionUID = 1L;
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
@Basic(optional = false)
@Column(name = "IDDoctor")
private Integer iDDoctor;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 45)
@Column(name = "Sirname")
private String sirname;
@Basic(optional = false)
@NotNull
@Size(min = 1, max = 45)
@Column(name = "Name")
private String name;
@Basic(optional = false)
@NotNull
@Column(name = "Patient_IDPatient")
private int patientIDPatient;
public Doctor() {
}
public Doctor(Integer iDDoctor) {
this.iDDoctor = iDDoctor;
}
public Doctor(Integer iDDoctor, String sirname, String name, int patientIDPatient) {
this.iDDoctor = iDDoctor;
this.sirname = sirname;
this.name = name;
this.patientIDPatient = patientIDPatient;
}
public Integer getIDDoctor() {
return iDDoctor;
}
public void setIDDoctor(Integer iDDoctor) {
this.iDDoctor = iDDoctor;
}
public String getSirname() {
return sirname;
}
public void setSirname(String sirname) {
this.sirname = sirname;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getPatientIDPatient() {
return patientIDPatient;
}
public void setPatientIDPatient(int patientIDPatient) {
this.patientIDPatient = patientIDPatient;
}
@Override
public int hashCode() {
int hash = 0;
hash += (iDDoctor != null ? iDDoctor.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 Doctor)) {
return false;
}
Doctor other = (Doctor) object;
if ((this.iDDoctor == null && other.iDDoctor != null) || (this.iDDoctor != null && !this.iDDoctor.equals(other.iDDoctor))) {
return false;
}
return true;
}
@Override
public String toString() {
return iDDoctor + sirname + name + " | ";
}
}
我有bean类：
package com.tsc.deo.beans;
import com.tsc.deo.entities.Doctor;
import java.io.Serializable;
import java.util.List;
import javax.ejb.Stateless;
import javax.inject.Named;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
/**
*
* @author IK
*/
@Stateless
@Named
public class DoctorSessionBean implements Serializable, DoctorSession, DoctorSessionLocal {
public DoctorSessionBean () {}
// Add business logic below. (Right-click in editor and choose
// "Insert Code > Add Business Method")
@PersistenceContext
private EntityManager em;
// private Logger log = null;
public EntityManager getEntityManager() {
try {
// Context ctx = (Context) new InitialContext().lookup("java:comp/env");
// return (EntityManager) ctx.lookup("persistence/LogicalName");
return em;
} catch (Exception e) {
// Logger.getLogger(getClass().getName()).log(Level.SEVERE, "exception caught", e);
// throw new RuntimeException(e);
e.printStackTrace(System.out);
throw new RuntimeException(e);
}
}
public List<Doctor> getDoctors() {
return getEntityManager().createNamedQuery("Doctor.findAll").getResultList();
}
public void insertDBDoctor(Doctor doc) {
EntityManager em = getEntityManager();
em.getTransaction().begin();
em.persist(doc);
em.getTransaction().commit();
em.close();
}
}
使用远程和本地接口：
package com.tsc.deo.beans;
import com.tsc.deo.entities.Doctor;
import java.util.List;
import javax.ejb.Remote;
import javax.persistence.EntityManager;
/**
*
* @author IK
*/
@Remote
public interface DoctorSession {
public EntityManager getEntityManager();
public List<Doctor> getDoctors();
}
package com.tsc.deo.beans;
import com.tsc.deo.entities.Doctor;
import java.util.List;
import javax.ejb.Local;
import javax.persistence.EntityManager;
/**
*
* @author IK
*/
@Local
public interface DoctorSessionLocal {
public EntityManager getEntityManager();
public List<Doctor> getDoctors();
}
我有一个servlet试图在DB中存储新实体（连接到DB工作正常）：
package com.tsc.deo.servlets;
import com.tsc.deo.beans.DoctorSessionBean;
import com.tsc.deo.entities.Doctor;
import java.io.IOException;
import java.io.PrintWriter;
import javax.ejb.EJB;
import javax.persistence.EntityManager;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
*
* @author IK
*/
@WebServlet(name = "TestUpdateDBServlet", urlPatterns = {"/TestUpdateDBServlet"})
public class TestUpdateDBServlet extends HttpServlet {
@EJB
private DoctorSessionBean doctorSessionBean;
/**
* Processes requests for both HTTP <code>GET</code> and <code>POST</code>
* methods.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
Doctor doc = new Doctor();
doc.setIDDoctor(8);
doc.setSirname("Материнка");
doc.setName("Оля");
doc.setPatientIDPatient(81);
doctorSessionBean.insertDBDoctor(doc);
response.setContentType("text/html;charset=UTF-8");
try (PrintWriter out = response.getWriter()) {
/* TODO output your page here. You may use following sample code. */
out.println("<!DOCTYPE html>");
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet TestUpdateDBServlet</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet TestUpdateDBServlet at " + request.getContextPath() + "</h1>");
out.println(doctorSessionBean.getDoctors());
out.println("</body>");
out.println("</html>");
}
}
// <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">
/**
* Handles the HTTP <code>GET</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Handles the HTTP <code>POST</code> method.
*
* @param request servlet request
* @param response servlet response
* @throws ServletException if a servlet-specific error occurs
* @throws IOException if an I/O error occurs
*/
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
processRequest(request, response);
}
/**
* Returns a short description of the servlet.
*
* @return a String containing servlet description
*/
@Override
public String getServletInfo() {
return "Short description";
}// </editor-fold>
}
运行应用程序后，我的浏览器中显示错误消息：
＆＃34; javax.servlet.ServletException：实例化servlet类com.tsc.deo.servlets.TestUpdateDBServlet时出错
在原因的根源上，它说它无法找到DoctorSessionBean：
＆＃34; javax.naming.NameNotFoundException：com.tsc.deo.beans.DoctorSessionBean＃com.tsc.deo.beans.DoctorSessionBean not found＆＃34;
这个问题的原因是什么以及如何纠正？
现在，NetBeans中的GlassFish 4.0正在弹出错误消息：
＆＃34;严重：Web应用程序[/ DEO]创建了一个类型为[org.glassfish.pfl.dynamic.codegen.impl.CurrentClassLoader $ 1]的键的ThreadLocal（值[org.glassfish.pfl.dynamic。 codegen.impl.CurrentClassLoader$1@2380e2]）和类型为[org.glassfish.web.loader.WebappClassLoader]的值（值[WebappClassLoader（delegate = true; repositories = WEB-INF / classes /）]）但未能删除当Web应用程序停止时。线程将随着时间的推移而更新，以避免可能的内存泄漏。＆＃34;
答案 0 :(得分：0)
在您的代码中
@Named
public class DoctorSessionBean implements
这意味着bean将名为doctorSessionBean。如果您没有指定名称，它将使用小写的bean名称。
look here for http://docs.oracle.com/javaee/6/tutorial/doc/gjbak.html information.
Giving Beans EL Names
To make a bean accessible through the EL, use the @Named built-in qualifier:
import javax.inject.Inject;
import javax.enterprise.context.RequestScoped;
import javax.inject.Named;
@Named
@RequestScoped
public class Printer {
@Inject @Informal Greeting greeting;
...
The @Named qualifier allows you to access the bean by using the bean name,
第一个
小写字母。例如，Facelets页面将bean称为打印机。
You can specify an argument to the @Named qualifier to use a nondefault name:
@Named("MyPrinter")
With this annotation, the Facelets page would refer to the bean as MyPrinter.