Exporting a Text file from Java Code

[Abhishek Rath]

Hi

I am trying to save the data from my Value Object into a text file and download that using Spring MVC. I am using the below code

    
    private void getDownload(HttpServletResponse response, List<ProductInfo> products) {
        
        StringBuffer buf= new StringBuffer();
        
        for (int i = 0; i < products.size(); i++) {
            ProductInfo productInfo = products.get(i);
            buf.append(productInfo.getSku());
            buf.append("\n");
        }
        Calendar currentDate = Calendar.getInstance();
        SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd_hhmmss");
        String fileName = "sku_" + formatter.format(currentDate.getTime()) + ".txt";
        response.setContentType("text/plain");
        response.setHeader("Content-Disposition", "attachment; filename=" + fileName);
        ServletOutputStream out;
        try {
            out = response.getOutputStream();
            out.println(buf.toString());
            out.flush();
            out.close();
        } catch (Exception e) {
           }
      }

This is creating a text file and addting the data to it and saving it to my local machine however in the Jetty Server Console I am getting the below error

java.lang.IllegalStateException: STREAM

How to get away from this exception?

Issue :2 -

When i update the code with some other text file writing code then I am getting the whole HTML page in the text file. What could be the reason for this?

FileUtils.writeStringToFile(new File(fileName), buf.toString());

[Bear Bibeault]

This fragment of code:

} catch (Exception e) {
       }

should cause flames to erupt from your keyboard. Nevver do this!

With this, you are telling the code to silently ignore any and all exceptions.

Either remove the try/catch block or handle the exception. Post back when you have discovered if any exceptions have been thrown in the try block.

[Bear Bibeault]

java.lang.IllegalStateException: STREAM

You need to post the entire stack trace so we can see what line of code caused the exception. I don't see how that can be caused by your code.

[Dave Tolls]

Bear Bibeault wrote:

java.lang.IllegalStateException: STREAM

You need to post the entire stack trace so we can see what line of code caused the exception. I don't see how that can be caused by your code.

I think it's a side effect.
Something else is trying to get the output stream or writer.

Possibly an error page?
All guesswork of course without the actual stack trace.

[Abhishek Rath]

The complete stack trace is :

java.lang.IllegalStateException: STREAM
at org.mortbay.jetty.Response.getWriter(Response.java:586)
at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:122)
at javax.servlet.ServletResponseWrapper.getWriter(ServletResponseWrapper.java:122)
at com.abc.ecommerce.mvc.views.ErrorView.render(ErrorView.java:63)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1180)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:950)
at com.abc.ecommerce.mvc.dispatcher.ContentDispatcher.doDispatch(ContentDispatcher.java:91)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:852)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:882)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:778)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:502)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1124)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:366)
at org.springframework.security.web.access.channel.ChannelProcessingFilter.doFilter(ChannelProcessingFilter.java:109)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:109)
at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:83)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
at com.abc.ecommerce.security.filters.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:99)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:187)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
at com.abc.ecommerce.security.filters.SessionContextIntegrationFilter.doFilter(SessionContextIntegrationFilter.java:242)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
at com.abc.ecommerce.security.filters.RequestContextSecurityFilter.doFilter(RequestContextSecurityFilter.java:84)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:378)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:167)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:259)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1115)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:361)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:756)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:417)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispatcher.java:334)
at org.mortbay.jetty.servlet.Dispatcher.forward(Dispatcher.java:126)
at org.tuckey.web.filters.urlrewrite.NormalRewrittenUrl.doRewrite(NormalRewrittenUrl.java:195)
at org.tuckey.web.filters.urlrewrite.RuleChain.handleRewrite(RuleChain.java:159)
at org.tuckey.web.filters.urlrewrite.RuleChain.doRules(RuleChain.java:141)
at org.tuckey.web.filters.urlrewrite.UrlRewriter.processRequest(UrlRewriter.java:90)
at org.tuckey.web.filters.urlrewrite.UrlRewriteFilter.doFilter(UrlRewriteFilter.java:417)
at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1115)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:361)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:756)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:417)
at org.mortbay.jetty.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:206)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:502)
at org.mortbay.jetty.HttpConnection$RequestHandler.headerComplete(HttpConnection.java:826)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:523)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:377)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:497)

[Dave Tolls]

So, something has thrown an exception and that has resulted in the server trying to show the error page, however the output stream has already been accessed and so an exception is thrown.

What you now need to do is ensure you are not eating exceptions. That is, that you have no catch blocks that do not log the exception or wrap and rethrow it.
There is one in your current servlet code, for example.