servlet可以更改另一个域的cookie [英] Can servlet change cookie of another domain
问题描述
我需要更改另一个域的Cookie值，我知道我们不能使用javascript。是否可以使用servlet？
我试着这样，但没有成功？是我错了吗？
我有两个web应用程序namly Cookie1和cookies2部署在localhost中的一个tomcat
cookie1应用程序的Servlet b
$ b
protected void doGet（HttpServletRequest request，HttpServletResponse response）throws ServletException，IOException {
response.setContentType（text / html）;
PrintWriter pw = response.getWriter（）;
// String Html =< HTML>< BODY> HI< / body>< / html>;
// pw.write（Html）;
Cookie cookie = new Cookie（__ utmz，Arvind）;
cookie.setDomain（http：// localhost：8080 / Cookie2）;
cookie.setPath（/）;
response.addCookie（cookie）;
//response.getWriter().write(Html）;
}
Cookie1应用程式Servlet b
$ b
protected void doGet（HttpServletRequest request，
HttpServletResponse response）throws ServletException，IOException {
System.out.println（CookieSetDm .doGet（））;
Cookie [] cookies = request.getCookies（）;
if（cookies！= null）{
for（int i = 0; i< cookies.length; i ++）{
System.out.println（cookies [i] .getName ）+<>+ cookies [i] .getValue（））;
}
}
}
出于安全考虑，您无法使用托管在其他域上的servlet或JavaScript修改一个域的cookie。请参见 RFC 6265，第4.1.2.3节：
用户代理将拒绝cookie，除非域属性
指定了包含源服务器的cookie的范围。
例如，用户代理将接受来自
foo.example.com的具有Domain
属性example.com或foo.example.com的Cookie，但是用户代理不接受具有
Domain属性bar.example.com或baz.foo.example.com的Cookie。
但是你可以在servlet / script中设置一个cookie，然后在同一主机上的另一个servlet /脚本中读取/修改cookie。您可以甚至读取或修改在一个端口上运行的服务器上设置的Cookie来自在同一主机名/域的另一个端口上运行的服务器的相同主机名/域 - 因此您可以让Tomcat在同一服务器上的两个不同端口上运行，并在两者之间交换Cookie。
请注意，您在第一个示例中调用 setDomain 不正确 - Cookie的此字段需要一个域名称而不是完整的URL。所以调用应该看起来像这样：
cookie.setDomain（localhost）;
另一个答案指出，某些浏览器会忽略 localhost ，所以你可能不想设置这个cookie的所有 - 这具有设置一个cookie的效果，只有返回到同一个主机设置它（大部分时间是你想要的）。
I need to change cookies value of another domain, I know that we can not do it using javascript. Is it possible using servlet ?
I am trying like this but no success? were am I going wrong? I have two web application namly Cookies1 and Cookies2 deployed in one tomcat in localhost
Servlet of cookie1 application
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
// String Html = "<HTML><BODY>HI</body></html>";
// pw.write(Html);
Cookie cookie = new Cookie("__utmz", "Arvind");
cookie.setDomain("http://localhost:8080/Cookie2");
cookie.setPath("/");
response.addCookie(cookie);
//response.getWriter().write(Html);
}
Servlet of cookie1 application
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {
System.out.println("CookieSetDm.doGet()");
Cookie[] cookies = request.getCookies();
if (cookies != null) {
for (int i = 0; i < cookies.length; i++) {
System.out.println(cookies[i].getName() + " <> "+ cookies[i].getValue());
}
}
}
You can't modify the cookies of one domain using a servlet or JavaScript hosted on another domain, for security reasons. See RFC 6265, section 4.1.2.3:
The user agent will reject cookies unless the Domain attribute specifies a scope for the cookie that would include the origin server. For example, the user agent will accept a cookie with a Domain attribute of "example.com" or of "foo.example.com" from foo.example.com, but the user agent will not accept a cookie with a Domain attribute of "bar.example.com" or of "baz.foo.example.com".
But you can set a cookie in a servlet/script and then read/modify the cookie in another servlet/script on the same host. You can even read or modify a cookie set on a server running on one port on the same hostname/domain from a server running on another port at the same hostname/domain - so you can have Tomcat running on two different ports on the same server and exchange cookies between the two.
Note that you're calling setDomain incorrectly in the first example - this field of the cookie takes a domain name and not a full URL. So the call should look like this:
cookie.setDomain("localhost");
As the other answer notes, some browsers ignore cookies for localhost, so you may want to not set this field of the cookie at all - this has the effect of setting a cookie that will only be returned to the same host that set it (which most of the time is what you want).
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