createpersonservlet.java

SUN的JAVA EE5源代码java_ee_sdk-5_03-preview-samples

/*
 * The contents of this file are subject to the terms 
 * of the Common Development and Distribution License 
 * (the License).  You may not use this file except in
 * compliance with the License.
 * 
 * You can obtain a copy of the license at 
 * https://glassfish.dev.java.net/public/CDDLv1.0.html or
 * glassfish/bootstrap/legal/CDDLv1.0.txt.
 * See the License for the specific language governing 
 * permissions and limitations under the License.
 * 
 * When distributing Covered Code, include this CDDL 
 * Header Notice in each file and include the License file 
 * at glassfish/bootstrap/legal/CDDLv1.0.txt.  
 * If applicable, add the following below the CDDL Header, 
 * with the fields enclosed by brackets [] replaced by
 * you own identifying information: 
 * "Portions Copyrighted [year] [name of copyright owner]"
 * 
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 */
package enterprise.web_jpa_war.servlet;

import enterprise.web_jpa_war.entity.Person;
import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;

import javax.persistence.PersistenceUnit;
import javax.persistence.EntityManagerFactory;
import javax.persistence.EntityManager;
import javax.annotation.Resource;
import javax.transaction.UserTransaction;


/**
 * The sevelet class to insert Person into database
 */
public class CreatePersonServlet extends HttpServlet {
    
    @PersistenceUnit
    //The emf corresponding to 
    private EntityManagerFactory emf;  
    
    @Resource
    private UserTransaction utx;

    
    /** Processes requests for both HTTP <code>GET</code> and <code>POST</code> methods.
     * @param request servlet request
     * @param response servlet response
     */
    protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException {
        assert emf != null;  //Make sure injection went through correctly.
        EntityManager em = null;
        try {
            
            //Get the data from user's form
            String id         = (String) request.getParameter("id");
            String firstName  = (String) request.getParameter("firstName");
            String lastName   = (String) request.getParameter("lastName");
            
            //Create a person instance out of it
            Person person = new Person(id, firstName, lastName);
            
            //begin a transaction
            utx.begin();
            //create an em. 
            //Since the em is created inside a transaction, it is associsated with 
            //the transaction
            em = emf.createEntityManager();
            //persist the person entity
            em.persist(person);
            //commit transaction which will trigger the em to 
            //commit newly created entity into database
            utx.commit();
            
            //Forward to ListPerson servlet to list persons along with the newly
            //created person above
            request.getRequestDispatcher("ListPerson").forward(request, response);
        } catch (Exception ex) {
            throw new ServletException(ex);
        } finally {
            //close the em to release any resources held up by the persistebce provider
            em.close();
        }
    }
    
    // <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
     */
    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
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
    
    /** Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }
    // </editor-fold>
}