session

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购物车

package session;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.Enumeration;
import java.util.Vector;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class CoursesServlet extends HttpServlet {

/**
* Constructor of the object.
*/
public CoursesServlet() {
super();
}

/**
* Destruction of the servlet. 
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}

/**
* The doGet method of the servlet. 
*
* This method is called when a form has its tag value method equals to get.
*
* @param request
* the request send by the client to the server
* @param response
* the response send by the server to the client
* @throws ServletException
* if an error occurred
* @throws IOException
* if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
 throws ServletException, IOException {

this.doPost(request, response);
}

/**
* The doPost method of the servlet. 
*
* This method is called when a form has its tag value method equals to
* post.
*
* @param request
* the request send by the client to the server
* @param response
* the response send by the server to the client
* @throws ServletException
* if an error occurred
* @throws IOException
* if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
 throws ServletException, IOException {

  response.setContentType("text/html;charset=gb2312");
  PrintWriter out = response.getWriter();
  HttpSession session = request.getSession();
  String sessionName = (String) session.getAttribute("name");

if (sessionName == null) {
 response.sendRedirect("ShoppingLogin.html");
 return;
 }
 String coursesSelect = request.getParameter("cname");
 if (coursesSelect != null) {
 Vector vCourses = (Vector) session.getAttribute("courses");
 if (vCourses == null) { // 判断用户是否是第一次选择课程，如果是第一次，则新建向量，然后将获取的课程名添加至向量，并将向量存入session
 vCourses = new Vector();
 vCourses.add(coursesSelect);
 session.setAttribute("courses", vCourses);
 } else {
 if(vCourses.contains(coursesSelect)){
 out.println(sessionName+",你以前选择过了"+coursesSelect+"<hr>");
 }else{
 vCourses.add(coursesSelect);
 }
 }

}
//显示我们要购买的课程


 String[] courses = { "c", "c++", "java", "java web", "vc#" };
 out.println(sessionName + ",请选择你要购买的课程： ");
 for (int i = 0; i < courses.length; i++) {
 out.println(courses[i]
 + "    <a href='CoursesServlet?cname="
 + courses[i] + "'>选择</a> ");
 }
 out.println("<hr>");

 Vector vCourses=(Vector) session.getAttribute("courses");
 out.print(sessionName+",你选择购买的课程是： ");
 if(vCourses!=null){
 for(Enumeration e=vCourses.elements();e.hasMoreElements();){
 out.println((String)e.nextElement()+" ");
 }
 }
}

public void init() throws ServletException {
// Put your code here
}

}