Servlet：响应提交后无法转发 [英] Servlet: Cannot forward after response has been committed

问题描述

我正在处理基于 geo-location 的内容的servlet页面，并且我想同时使用 sendRedirect 和 forward 在一起;例如;您可以从 France ; 来浏览 example.com/aPage.jsp 首先，我希望servlet将您重定向到 example.com/fr/aPage.jsp ，然后转发给资源 page。

这就是我在servlet中的内容：

  public void doGet（HttpServletRequest request，HttpServletResponse response）throws ServletException，IOException {
 .... 
 response.sendRedirect（REDIRECT_URL_BASED_ON_GEO）; 
 //重定向转发资源页面后
 RequestDispatcher view = request.getRequestDispatcher（RESOURCES_PAGE）; 
 view.forward（request，response）; 
 ... 
} 
  

但是我得到：

  java.lang.IllegalStateException：在提交响应后无法转发
  

我知道错误出现，因为我不能同时使用 sendRedirect 和转发一个接一个，但我不知道如何达到我想要的（如上所述）没有这个。

任何帮助？

解决方案

  response.sendRedirect（REDIRECT_URL_BASED_ON_GEO）; 
 //重定向后转发资源页面
  

在该行之后，您的响应开始写入clinet。

您正在尝试向其添加更多数据。

服务器的已经完成，编写响应标题并写入内容的主体，以及点你试图写更多的头 - 当然它不能倒带。

所以，在处理servlet的时候， / p>

在重定向或转发添加return语句之前完成逻辑。执行结束。

I'm working on servlet page that renders content based on geo-location, and I want to use both sendRedirect and forward together; e.g; you browse example.com/aPage.jsp from France; first I want the servlet to redirect you to example.com/fr/aPage.jsp and then forward you to the resources page.

This is what I have in my servlet:

public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  ....
  response.sendRedirect(REDIRECT_URL_BASED_ON_GEO);
  // after redirect forward the resources page
  RequestDispatcher view = request.getRequestDispatcher(RESOURCES_PAGE);
  view.forward(request, response);
  ...
}

But I get:

java.lang.IllegalStateException: Cannot forward after response has been committed

I know the error appears because I can't use both sendRedirect and forward one after another, but I don't know how to achieve what I want (as described above) without this.

any help?

解决方案

 response.sendRedirect(REDIRECT_URL_BASED_ON_GEO);
  // after redirect forward the resources page

After that line , Your response start writing to clinet.

And you are trying to add additional data to it.

The server has already finished writing the response header and is writing the body of the content, and which point you are trying to write more to the header - of course it cant rewind.

So,Thumb rule while dealing with servlet is

Finish your logic before redirect or forward add return statement.So execution ends there .

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