来自jsp的response.sendRedirect（）：include被忽略了？ [英] response.sendRedirect() from jsp:include being ignored?

问题描述

我有一个jsp文件，其中包含另一个jsp文件来检查一些值等等：

I've got a jsp file, which includes another jsp file to check some values and such:

< jsp：include page =setup.jsp/>

在setup.jsp中我有一些条件代码可以确定是否需要一些值在会话中设置，如果没有重定向到不同的页面。或者至少它应该是，但重定向似乎被忽略了。

Inside the setup.jsp I've got some conditional code which determines if some needed values are set in the session and if not redirects them to a different page. Or at least it is supposed to, but the redirect seems to be getting ignored.

System.err.println("Redirecting!");
response.sendRedirect("http://www.google.com");
return;

我看到重定向！登录到控制台，但页面继续并正常呈现。我有curl转储标题给我，并看到响应是 HTTP / 1.1 200 OK 所以它肯定没有发送302重定向。

I see "Redirecting!" get logged to the console, but the page continues on and renders normally. I had curl dump the headers for me and saw that the response is HTTP/1.1 200 OK so it definitely isn't sending a 302 redirect.

知道问题是什么以及如何解决这个问题？

Any idea what the problem is and how I can fix this?

编辑：我已经确认我的回复尚未提交。 response.isCommitted（）返回 false 表示尚未发送状态代码和标题。

I have verified that my response is not yet committed. response.isCommitted() returns false meaning the status code and headers have not been sent yet.

编辑2：我曾尝试在许多其他地方调用 response.sendRedirect（），并发现我可以在之前成功重定向。 JSP中的重定向似乎被忽略了，如果我尝试在jsp之后重定向，那么我会得到一个非法的状态异常，因为响应已经被提交了。

EDIT 2: I've tried calling response.sendRedirect() in many other places and find that I can successfully redirect before the . The redirect inside the JSP seems to be ignored and if I try to redirect right AFTER the jsp then I get an illegal state exception because the response has already been committed.

推荐答案

< jsp：include> 在封面下使用 RequestDispatcher #include（） 。单击链接以查看javadoc。以下是相关摘录（强调我的）：

The <jsp:include> uses under the covers RequestDispatcher#include(). Click the link to see the javadoc. Here's an extract of relevance (emphasis mine):

...

...

ServletResponse对象的路径元素和参数与调用者保持不变。 包含的servlet无法更改响应状态代码或设置标头;任何改变的尝试都会被忽略。

The ServletResponse object has its path elements and parameters remain unchanged from the caller's. The included servlet cannot change the response status code or set headers; any attempt to make a change is ignored.

...

HttpServletResponse＃sendRedirect（） 基本上将HTTP响应状态设置为 302 和HTTP 位置目标网址的标头。因此完全被忽略了。

The HttpServletResponse#sendRedirect() basically sets the HTTP response status to 302 and the HTTP Location header to the target URL. It is thus totally being ignored.

更深层次的问题是你滥用JSP作为页面控制器/过滤器。您应该使用正常的 servlet 或过滤器这个在JSP之前运行的类。

The deeper problem is that you're abusing JSP as a page controller/filter. You should actually be using a normal servlet or filter class for this which runs far before JSP.

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