使用Session在JSP页面间传递表单内容

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用 Session保存表单提交的内容,基本原理是用Session下的setAttribute() 与　getAttribute()　方法来保存与获取一个参数．

1．在MY ECLIPSE下创建一个WEB PROJECT,在默认路径下建立两个Session的JSP文件,其中Session.JSP用来提交表单内容, Session1.JSP用来获取由Session保存的参数内容.

2.　创建一个servlet文件，用以处理由Session．JSP提交的表单内容,并将其放入request.setAttribute()方法中．

注：在servlet中不能直接使用Session下的setAttribute() 与　getAttribute()　方法，在头文件中必须包含javax.servlet.Http.*; 创建Session对象时要先声明这个对象,使用语法为:

Http Session session=request.getSession();

具体代码如下：

Session．JSP

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <head> </head> <body> <form action="Form"> A :<input type="text" name="a" size=5><p> B :<input type="text" name="b" size=5><p> C :<input type="text" name="c" size=5><p> <input type=submit value="Submit"> </form> </body></html>
Session1．JSP

<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html> <body> <% List<String> array=new ArrayList(); // List 用以保存表单中的每一个值 array=(List<String>)request.getAttribute("array"); out.print("<h2>Session save A,B,C :</h2><p>"); //JDK for(String name:array) //JDK1.4以后的版本支持的　foreach　语法 { out.println(name); out.print("<p>"); } %> </body></html>

Form.java // servlet文件

import java.io.IOException;import java.io.PrintWriter;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.*;import java.util.*;public class Form extends HttpServlet { /** * Constructor of the object. */ public Form() { super(); } /** * Destruction of the servlet. <br> */ public void destroy() { super.destroy(); // Just puts "destroy" string in log // Put your code here } /** * The doGet method of the servlet. <br> * * 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 { response.setContentType("text/html"); PrintWriter out = response.getWriter(); String a=(String)request.getParameter("a"); String b=(String)request.getParameter("b"); String c=(String)request.getParameter("c"); List<String> array=new ArrayList(); array.add(a);array.add(b);array.add(c); HttpSession session=request.getSession(true); session.setAttribute("array",array); request.setAttribute("array",session.getAttribute("array")); getServletConfig().getServletContext().getRequestDispatcher( "/session1.jsp").forward(request, response); } /** * The doPost method of the servlet. <br> * * 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 { doGet(request,response); } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occurs */ public void init() throws ServletException { // Put your code here }}