JSP登錄中Session的用法實例詳解

%@ page language="java" contentType="text/html; charset=utf-8"
  pageEncoding="utf-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=utf-8">
title>Insert title here/title>
/head>
body>
 div style="float:left;margin-top:100px;margin-left:200px;width:400px;height:300px;background:gray;">
 form action="IndexServlet" method="post">
 div style="float:left;width:400px;height:30px;background:gray;margin-top:50px">
  div style="margin-left:70px;float:left;line-height:30px">賬號:/div>input style="disply:block;float:left;width:200px;height:30px;border:none;" type="text" name="user"/>
 /div>
 div style="float:left;width:400px;height:30px;background:gray;margin-top:50px">
  div style="margin-left:70px;float:left;line-height:30px">密碼:/div>input style="disply:block;float:left;width:200px;height:30px;border:none;" type="text" name="password"/>
 /div>
 div style="float:left;margin-top:50px;width:400px;height:30px;background:gray;">
  input style="float:left;width:60px;height:30px;margin-left:170px;border:none;" type="submit" name="ok" value="登錄"/>
 /div>
 /form>
 /div>
/body>
/html>

import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
 * Servlet implementation class IndexServlet
 */
@WebServlet("/IndexServlet")
public class IndexServlet extends HttpServlet {
 private static final long serialVersionUID = 1L;
    
  /**
   * @see HttpServlet#HttpServlet()
   */
  public IndexServlet() {
    super();
    // TODO Auto-generated constructor stub
  }
 
 /**
 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 // TODO Auto-generated method stub
 response.getWriter().append("Served at: ").append(request.getContextPath());
 }
 
 /**
 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
 */
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 // TODO Auto-generated method stub
 request.setCharacterEncoding("utf-8");
 String user = request.getParameter("user");
 String password = request.getParameter("password");
 
 String path = request.getContextPath();
 HttpSession session=request.getSession();
 
 if ("1".equals(user)  "1".equals(password)) {
  
  session.setAttribute("name", user);
  response.sendRedirect(path + "/success.jsp");
  
 }else{
  response.sendRedirect(path + "/Index.jsp");
 }
 }
 
}

%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
%
 String path = request.getContextPath();
%>
%
 Object name = session.getAttribute("name");
 if(name==null){
 response.sendRedirect(path+"/Index.jsp");
 }
%>
html>
 head>
 title>成功頁面/title>
 /head>
 body>
 恭喜你，騷年，%=session.getAttribute("name") %>,成功登陸了！
 a href="out.jsp" rel="external nofollow" >注銷/a>
 /body>
/html>

%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
html>
head>
meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
title>Insert title here/title>
/head>
body>
 % 
 String path = request.getContextPath();
 %>
 %
   session.removeAttribute("name");
   response.sendRedirect(path+"/Index.jsp");
  %>
/body>
/html>