getOutputStream() has already been called for this response on second servlet request

Question

hello i have a problem that I cannot put my finger on.....

servletResp.setHeader("Expires","0")
servletResp.setHeader("Cache-Control","must-revalidate, post-check=0, pre-check=0")
servletResp.setHeader("Pragma","public")
servletResp.setHeader("Content-Disposition","inline; filename=invoice.pdf")

servletResp.setContentType("application/pdf")
servletResp.setContentLength( outStream.size())
servletResponseStream.write(outStream.toByteArray())
outStream.close()
servletResponseStream.flush()
servletResponseStream.close()

In the above code assume that outStream has a read in pdf file. The code renders fine on first request. On second request I get:

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

it doesn't matter what outputstream is. Even if I make a brand new byte[2] and write that the same result happens. On first request the server responds fine. On second the above exception happens....

Any help would be welcome

Answer 1

The code in your question doesn't call getOutputStream() , or do anything that would cause it to be called. So I'd conclude that the cause of the exception is somewhere else.

The bottom line is that you can only call ServletResponse.getOutputStream() and/or getWriter() once for a given response. Somewhere, your application is calling getOutputStream or getWriter more than once.