java – Spring：已经为此响应调用了getOutputStream()

我知道还有很多其他帖子处理同样的错误,但所有这些都是关于JSP / GSP页面或者在我的情况下对其他任何不太有用的原因.我正在使用 Spring MVC和Thymeleaf.以下功能用于下载文件.

@RequestMapping(value = "/test/download/*", method = RequestMethod.GET)
public String getFile(HttpServletResponse response)
{

    ServletOutputStream stream = null;
    try
    {
        stream = response.getOutputStream();

        MultipartFile f = test.getFile();

        InputStream is = f.getInputStream();
        IOUtils.copy(is, stream);
        response.flushBuffer();

        stream.flush();
        stream.close();

    } catch(Exception ex)
    {

    }

    return "test";

}

它确实有效,所以它不是一个问题,但在控制台中,我总是收到以下错误：

2014-01-10T09:28:09.053+0100  SEVERE  Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception  [Request processing failed; nested exception is java.lang.IllegalStateException: getOutputStream() has already been called for this response] with root cause
java.lang.IllegalStateException: getOutputStream() has already been called for this response
at org.apache.catalina.connector.Response.getWriter(Response.java:638)
at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:214)
at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:105)
at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:105)
at org.springframework.security.web.context.SaveContextOnUpdateOrErrorResponseWrapper.getWriter(SaveContextOnUpdateOrErrorResponseWrapper.java:125)
at org.thymeleaf.spring3.view.ThymeleafView.renderFragment(ThymeleafView.java:335)
at org.thymeleaf.spring3.view.ThymeleafView.render(ThymeleafView.java:190)
[...]

据我所知,getOutputStream()只被调用一次.此外,整个功能被try-catch-block包围.所以我想知道,这个错误来自哪里？

最佳答案

如果返回’test’,则在使用响应outputStream返回二进制文件后,指示控制器将您发送到某个视图.这是一个如何管理这个的想法：

Downloading a file from spring controllers

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