I am getting an exception: java.lang.IllegalStateException: getOutputStream() has already been called for this response

Question

I want to write code to download a file which is persisted in my system

Here is my code:

In a controller class I have following mapping

@RequestMapping(value = "/processFile", method = RequestMethod.POST)
    public @ResponseBody ModelAndView downloadFileProcess(
            @RequestParam("file") File originalFile,
            @RequestParam("action") String action, HttpServletResponse response) {

        ModelAndView model = new ModelAndView();
        model.setViewName("error");
        System.out.println("");
        System.out.println("Action: "+action);
        model.addObject("message", "Action:" + action);
        try {
            utility.downloadFile(originalFile, response);
            message = "The file was downloaded successfully";

        } catch (IOException e) {
            e.printStackTrace();
            message = "The process failed due to following reason: "
                    + e.getMessage();
        } catch (Exception e) {
            e.printStackTrace();
            message = "The process failed due to following reason: "
                    + e.getMessage();
        }
        model.setViewName("success");
        model.addObject("message", message);
        return model;
    }

The method in the utility class is below:

public void downloadFile(File originalFile, HttpServletResponse response)
            throws FileNotFoundException, IOException {

        response.setHeader("Content-Disposition", "attachment; filename="
                + originalFile.getName());
        IOUtils.copy(
                new FileInputStream(new File(String.valueOf(originalFile))),
                response.getOutputStream());
        response.flushBuffer();

    }

As I want to download the file, I have to use response.getoutputstream() .

But I am getting the following exception:

java.lang.IllegalStateException: Cannot call sendRedirect() after the response has been committed
    at org.apache.catalina.connector.ResponseFacade.sendRedirect(ResponseFacade.java:482)
    at org.springframework.web.servlet.view.RedirectView.sendRedirect(RedirectView.java:548)
    at org.springframework.web.servlet.view.RedirectView.renderMergedOutputModel(RedirectView.java:279)
    at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:267)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1221)
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1005)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:952)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:77)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1736)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1695)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

2015-05-31 12:42:07.547 ERROR 15009 --- [nio-8080-exec-4] o.a.c.c.C.[.[.[/].[dispatcherServlet]    : Servlet.service() for servlet dispatcherServlet threw exception

java.lang.IllegalStateException: getOutputStream() has already been called for this response
    at org.apache.catalina.connector.Response.getWriter(Response.java:678)
    at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:213)
    at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:104)
    at org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$SpelView.render(ErrorMvcAutoConfiguration.java:187)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1221)
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1005)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:952)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
    at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:604)
    at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:543)
    at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:467)
    at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:342)
    at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:434)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:205)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1736)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1695)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)

2015-05-31 12:42:07.551 ERROR 15009 --- [nio-8080-exec-4] o.a.c.c.C.[Tomcat].[localhost]           : Exception Processing ErrorPage[errorCode=0, location=/error]

org.springframework.web.util.NestedServletException: Request processing failed; nested exception is java.lang.IllegalStateException: getOutputStream() has already been called for this response
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:973)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:863)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:646)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:837)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
    at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:748)
    at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:604)
    at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:543)
    at org.apache.catalina.core.StandardHostValve.custom(StandardHostValve.java:467)
    at org.apache.catalina.core.StandardHostValve.status(StandardHostValve.java:342)
    at org.apache.catalina.core.StandardHostValve.throwable(StandardHostValve.java:434)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:205)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1736)
    at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1695)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalStateException: getOutputStream() has already been called for this response
    at org.apache.catalina.connector.Response.getWriter(Response.java:678)
    at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:213)
    at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:104)
    at org.springframework.boot.autoconfigure.web.ErrorMvcAutoConfiguration$SpelView.render(ErrorMvcAutoConfiguration.java:187)
    at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1221)
    at org.springframework.web.servlet.DispatcherServlet.processDispatchResult(DispatcherServlet.java:1005)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:952)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:870)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:961)
    ... 27 common frames omitted

Answer 1

You want a single request to have two different responses:

• one which contains the bytes of the downloaded file as its body
• one which contains an HTML page generated by the success view

That does not make sense. It can only be one or the other. If you want the request to download a file, then you shouldn't return a ModelAndView. The method should return void.

Also, the method should not be annotated with @ResponseBody .

AFAIK, the way download sites generate a success page and a file download at the same time simply consists in responding with a HTML page containing an iframe, and have the iframe pointing at the URL for the actual file download.

Answer 2

1. HttpServletResponse.getOutputStream()

   • Used to write binary data to the client.
   • Data written to the client is not encoded.
   • Once flush() is called, data is flushed to the client.
   • IllegalStateException will be thrown if the getWriter() method has been called on this response object.

2. HttpServletResponse.getWriter()

   • Returns a PrintWriter object which can be used to write character text (non-binary) data to the client.
   • Data sent to the client is encoded either using default encoding scheme or user provided.
   • Once flush() is called, data is flushed to the client.
   • IllegalStateException will be thrown if the getOutputStream() method has already been called for this response object

One key usage difference between 2 is that getOutputStream() is for sending binary data to client and getWriter() is for sending encoded text data.

Bottom line: Either of the above 2 methods should be used to flush data to client, and not both, and developer has to make sure that it is properly handled, specially when doing things in a non-servlet class.

Answer 3

This is the problem with PrintWriter.getWriter() and HttpServletResponse.getOutputStream() both of which try to flush the data to client.

You are already using response.getOutputStream() and response.flushBuffer() , which means that you are trying to flush the content to client, and then finally when your downloadFileProcess() is returning, Springs is also trying to flush the content using PrintWriter.getWriter() so you get

java.lang.IllegalStateException: getOutputStream() has already been called for this response

Use code as below to send some content to client without making your method as void, and that should help.

String content = null;
IOUtils.copy(new FileInputStream(new File(String.valueOf(originalFile))), content );
PrintWriter out = response.getWriter();
out.println(content);

On a side note, why you are doing model.setViewName("error"); and model.addObject("message", "Action:" + action); in the start? I think either you should not have it because you are overriding in the end or they are better fitted in the CATCH blocks.

Answer 4

I solved the problem that way:

ApplicationContext context = new FileSystemXmlApplicationContext();
Resource resource = context.getResource("file:" + exFile.getPath());

File file = new File(exFile.getPath());
try {
   response.setHeader("Content-Disposition", "attachment; filename="                 + file.getName());
   InputStream is = resource.getInputStream();
   IOUtils.copy(is, response.getOutputStream());

} catch (IOException e) {
    e.printStackTrace();
}