使用Session在JSP页面间传递表单内容
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
}
}
下图为我在my eclipse 下创建的Web project 结构图：