How to fix exception: getOutputStream() has already been called for this response?

Question

I went through the answers/discussion about the same/similar issue and find out that I should be using "response" method either to download file or to get HTML page at one time. In my case after the successful download of the file, I want to show success alert message. And when I use "response" method to download file and to print success alert message I always get: getOutputStream() has already been called for this response exception.

What is the correct way to solve this problem?

Below is the section of my code:

// Write data in the excel
            ServletOutputStream out = response.getOutputStream(); => It successfully creates excel file
            workbook.write(out);

            // Close output stream and workbook
            workbook.close();
            out.flush();
            out.close();

            PrintWriter pw = response.getWriter(); => My problem is here!!
            response.setContentType("text/html");
            pw.println("<script type=\"text/javascript\">");
            pw.println("alert('" + message + "');");
            pw.println("history.back();");
            pw.println("</script>");

What happens when you just flush and not close the `out` object? — aksappy, Jun 17 '19 at 18:49

score 0 · Answer 1 · answered Jun 17 '19 at 18:42

0

You are trying to return two objects in the response of the same HTTP request. This is not how HTTP works. No browser will support that.

AFAIK, there's no way to detect "download complete" event in javascript.

answered Jun 17 '19 at 18:42

Mateusz Stefek

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I found out that One request One response rule of http. So my question is- after successful download of file how to print alert message? – sä-röze Jun 17 '19 at 18:54
https://stackoverflow.com/questions/1106377/detect-when-browser-receives-file-download – Mateusz Stefek Jun 17 '19 at 18:58

How to fix exception: getOutputStream() has already been called for this response?

1 Answers1