jsp课程笔记之session（二）

兮动人

发布于 2021-06-11 11:17:44

7960

注销session及共享session案例

<%@ 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>
	<form action="check.jsp" method="post">
		用户名:<input type="text" name="uname"><br/>
		密码:<input type="password" name="upwd"><br/>
		<input type="submit" value="登陆"><br/>
	</form>
</body>
</html>

check.jsp

<%@ 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>
		<%
			request.setCharacterEncoding("utf-8") ;
			String name = request.getParameter("uname");
			String pwd = request.getParameter("upwd");
			if(name.equals("zs") && pwd.equals("abc")){//假设 zs abc
				//只有登录成功，session中才会存在uname /upwd
				session.setAttribute("uname", name)		 ;
				session.setAttribute("upwd", pwd)		;
				System.out.println("sessionId"+session.getId());
				
				//Cookie cookie = new Cookie("uname" ,namxe);
				//response.addCookie(cookie) ;
				//服务端在第一次响应客户端时，会发送一个 JSESSIONID的cookie
				
				//session.setMaxInactiveInterval(10) ;
				
				request.getRequestDispatcher("welcome.jsp").forward(request, response) ;
				
			
			}else{
				//登录失败
				response.sendRedirect("login.jsp") ;
			}
		
		%>
</body>
</html>

welocame.jsp

<%@ 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>
	欢迎您：
		<%
			String name = (String)session.getAttribute("uname") ;
			//如果 用户没有登录，而是直接 通过地址栏 访问welcome.jsp,则必然获取到的name是null
			if(name!=null){
				out.print(name);
				
				
				System.out.println();
		%>
			<a href="invalidate.jsp">注销</a>
		<%
				
			}else{//如果没有登录，应该跳转登录页面
				response.sendRedirect("login.jsp");
			}
			
		
		%>
</body>
</html>

a.jsp

<%@ 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>
		<%

			out.print(session.getAttribute("uname"));
			Cookie[] cookies = request.getCookies();
			for(Cookie cookie:cookies){
				if(cookie.getName().equals("JSESSIONID")){
					System.out.print("JSESSIONID"+cookie.getValue());
				}
			}
		
		
		%>
</body>
</html>

通过登录和直接访问a.jsp在控制台分别输出