java.lang.IllegalStateException content - disposition

Question

I am trying to use content - disposition to save something from server to client computer. When I click on button in jsp, dialog opens and I choose to save file. File is saved but I get this exception. I have read on other similar topics something like "Somewhere, your application is calling getOutputStream or getWriter more than once." but I don't know/understand where?

@Controller
public class ExportPhonebook2 {

    @Autowired
    private PhoneBookService phoneBookSer;

    private void setResponseHeader(HttpServletResponse response, String imenikTXT, File file){
    response.setHeader("Content-Length", "" + file.length());
    response.setContentType("application/txt; charset=UTF-8");
    response.setHeader("content-disposition", "attachement; filename=imenik.txt" );
    response.setHeader("Content-Transfer-Encoding", "binary");
    } 

    @RequestMapping(value = "/exportPhonebook.html", method = RequestMethod.POST)
    public String exportPhonebook(Model model, HttpServletResponse response) {

        List<User> listOfAllUsers = phoneBookSer.fetchAllUsers();
        String imenik = "";

        for (User user : listOfAllUsers) {
            imenik = imenik + user.getPrezime() + " " + user.getIme() + ", Telefon: " + user.getTelefon() + ";\r\n" ;
        }


        try {

            File file = new File("c:\\imenik.txt");
            setResponseHeader(response, "imenik.txt", file);
            FileInputStream fileIn;
            fileIn = new FileInputStream(file);

            OutputStream outTXT = response.getOutputStream();

            byte[] outputByte = new byte[8192];
            //copy binary contect to output stream
            while(fileIn.read(outputByte, 0, 8192) != -1){
                outTXT.write(outputByte, 0, 8192);
            }
            fileIn.close();
            outTXT.flush();
            outTXT.close();
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
    } catch (IOException e) {
               // TODO Auto-generated catch block
                e.printStackTrace();
    }

            return "homepage";
    }
}

stacktrace:

Exception initializing page context
java.lang.IllegalStateException: Cannot create a session after the response has been   committed
at org.apache.catalina.connector.Request.doGetSession(Request.java:2705)
at org.apache.catalina.connector.Request.getSession(Request.java:2231)
at org.apache.catalina.connector.RequestFacade.getSession(RequestFacade.java:899)
at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:229)
at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:572)
at org.apache.catalina.core.ApplicationHttpRequest.getSession(ApplicationHttpRequest.java:517)
at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:238)
at javax.servlet.http.HttpServletRequestWrapper.getSession(HttpServletRequestWrapper.java:238)
at org.apache.jasper.runtime.PageContextImpl._initialize(PageContextImpl.java:146)
at org.apache.jasper.runtime.PageContextImpl.initialize(PageContextImpl.java:125)
at org.apache.jasper.runtime.JspFactoryImpl.internalGetPageContext(JspFactoryImpl.java:112)
at org.apache.jasper.runtime.JspFactoryImpl.getPageContext(JspFactoryImpl.java:65)
at org.apache.jsp.WEB_002dINF.jsp.homepage_jsp._jspService(homepage_jsp.java:58)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:391)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.ApplicationDispatcher.invoke(ApplicationDispatcher.java:684)
at org.apache.catalina.core.ApplicationDispatcher.doInclude(ApplicationDispatcher.java:593)
at org.apache.catalina.core.ApplicationDispatcher.include(ApplicationDispatcher.java:530)
at org.springframework.web.servlet.view.InternalResourceView.renderMergedOutputModel(InternalResourceView.java:229)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1047)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:817)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:644)
at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:560)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:304)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:328)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:116)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:95)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:100)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:79)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:35)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:119)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:187)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:80)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:340)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:175)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:237)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:167)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:498)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:394)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:243)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:166)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

Answer 1

This particular exception is caused because Spring MVC apparently needs to create a session during rendering of the view, but couldn't because the response is already committed with the file download. But your real problem is bigger, Spring MVC should not be rendering a view at all.

You need to tell Spring MVC to not render a view after having taken over the control of the HTTP response from Spring MVC. It is otherwise trying to append the rendered view to the end of the HTTP response which would only corrupt the file download.

I don't do Spring MVC, so I can't answer from top of head, but it appears that just returning void instead of String from the controller's action method should be sufficient in order to tell Spring MVC to not render a view.

Answer 2

java.lang.IllegalStateException: Cannot create a session after the response has been committed

Session creation requires a session cookie to be written to the HTTP header, before the body. Something is trying to create a session after you've flushed and closed your response.

Consider creating the session prior to writing the response.