cookie的路径问题

偏执的太偏执、 2022-06-08 14:48 140阅读 0赞

新建两个页面 1.JSP  和   2.JSP:

![Center][]

1.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    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>
        <base href="<%=basePath%>">
        
        <title>My JSP '1.jsp' starting page</title>
        
    	<meta http-equiv="pragma" content="no-cache">
    	<meta http-equiv="cache-control" content="no-cache">
    	<meta http-equiv="expires" content="0">    
    	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    	<meta http-equiv="description" content="This is my page">
    	
    
      </head>
      
      <body>
        <%
          Cookie[] cookies=request.getCookies();
        if(cookies.length>0){
        	for(Cookie cookie:cookies){
        		%>
        		<%= cookie.getValue() %>
        		<% 
        	}
        }else{
        	%>
        	<%= "没有值啊" %>
        	<% 
        }
        %>
      </body>
    </html>

2.jsp:

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
    <%
    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>
        <base href="<%=basePath%>">
        
        <title>My JSP '2.jsp' starting page</title>
        
    	<meta http-equiv="pragma" content="no-cache">
    	<meta http-equiv="cache-control" content="no-cache">
    	<meta http-equiv="expires" content="0">    
    	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    	<meta http-equiv="description" content="This is my page">
    	
    
      </head>
      
      <body>
        <%
          Cookie cookie=new Cookie("name","sasa");
        response.addCookie(cookie);
        %>
        <a href="<%=basePath%>cookie/1.jsp">to 1.jsp</a>
      </body>
    </html>

由2.jsp跳转到1.jsp，查看1.jsp:

![Center 1][]

可以看到,1.jsp能接收到2.jsp传送的cookie.

现在将1.jsp和2.jsp的位置互换：

![Center 2][]  
由2.jsp跳转到1.jsp，查看1.jsp:

![Center 3][]

可以看到1.jsp并没有接收到2.jsp传过来的cookie.

由此可以得出结论：

cookie的作用范围可以在当前目录和当前目录的子目录，但是不能位于当前目录的上一级目录中。

如果希望扩大cookie的作用域，则需要修改2.jsp的内容：

<%
          Cookie cookie=new Cookie("name","sasa");
     //设置cookied作用范围 cookie.setPath(request.getContextPath());
        response.addCookie(cookie);
        %>

再次测试:

![Center 4][]

OK!!!

[Center]: /images/20220608/004d004cc03244689f9b30e9a7bc22dd.png
[Center 1]: /images/20220608/8e9508aaa8d44009a2fa31bcdd05cbe9.png
[Center 2]: /images/20220608/b5d4fab162fd4a418dc7101dffb43f55.png
[Center 3]: /images/20220608/b5c19de8f41847f18487b1aa941430b0.png
[Center 4]: /images/20220608/ab221022ffed48869b66f1a8a98694de.png