userservlet.java

这个是j2eejava web 编程精要十五讲的全部源码。对学习java web编程的人来说是很能得的资料

package user;

import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import org.hibernate.*;


public class userServlet extends HttpServlet {
  private static final String CONTENT_TYPE = "text/html; charset=GB2312";
  //Initialize global variables
  public void init() throws ServletException {
  }
  //Process the HTTP Get request
  public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    String username = request.getParameter("username");
    if (username == null) {
      username = "";
    }
    String password = request.getParameter("password");
    if (password == null) {
      password = "";
    }
    String age1 = request.getParameter("age");
    if (age1 == null) {
      age1 = "0";
    }

    String action = request.getParameter("action");
    System.out.println("action="+action);
    if (action == null) {
      action = "";
    }


    int age = Integer.parseInt(age1);

    response.setContentType(CONTENT_TYPE);
    PrintWriter out = response.getWriter();

    User user = new User();  //生成User实例
    user.setUsername(username);
    user.setPassword(password);
    user.setAge(age);

    Session session;
    Transaction tx;
    Query query;

    if(action.equals("save")) {

    session = HibernateUtil.currentSession(); //生成Session实例
     tx = session.beginTransaction();

      try {
      session.save(user); //保存持久类对象
      tx.commit(); //提交到数据库
      session.close();
      response.sendRedirect("reply.jsp"); //跳转到回复页面
    }catch (HibernateException e) {
      e.printStackTrace();
      tx.rollback();
     }
    }

    if(action.equals("update")) {

      session = HibernateUtil.currentSession(); //生成Session实例
       tx = session.beginTransaction();

       try {
      query = session.createQuery("from User u where u.username=?");
      query.setString(0,username);
      List list = query.list();
      for(int i=0;i<list.size();i++) {
        User u = (User) list.get(i);
        User u1 = (User) session.get(User.class, new Integer(u.getId()));
        u1.setPassword(password);
        u1.setAge(age);
        //User u1 = (User)session.createQuery("from User u where u.username='walker'").uniqueResult();
        session.update(u1);
     }
   // session.save(user); //保存持久类对象
    tx.commit(); //提交到数据库
    session.close();
    response.sendRedirect("reply.jsp"); //跳转到回复页面
    }catch (HibernateException e) {
    e.printStackTrace();
    tx.rollback();
   }
}


    if(action.equals("delete")) {

   session = HibernateUtil.currentSession(); //生成Session实例
    tx = session.beginTransaction();

     try {
       query = session.createQuery("from User u where u.username=?");
       query.setString(0,username);
       List list = query.list();
       for(int i=0;i<list.size();i++) {
         User u = (User) list.get(i);
         User u1 = (User) session.get(User.class, new Integer(u.getId()));
         //User u1 = (User)session.createQuery("from User u where u.username='walker'").uniqueResult();
         session.delete(u1);
      }
    // session.save(user); //保存持久类对象
     tx.commit(); //提交到数据库
     session.close();
     response.sendRedirect("reply.jsp"); //跳转到回复页面
   }catch (HibernateException e) {
     e.printStackTrace();
     tx.rollback();
    }
   }

  }
  //Process the HTTP Post request
  public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doGet(request, response);
  }
  //Clean up resources
  public void destroy() {
  }
}