Overriding getWriter(), server returns error 503 (weird?)

Hi I am following the code from this link: Capture and log the response body

However the server return error 503 which is really weird?

This is my code:

        final CopyPrintWriter writer = new CopyPrintWriter(servletresponse.getWriter());
        chain.doFilter(servletrequest, new MyResponseWrapper( 
                (HttpServletResponse) servletresponse){
                @Override
                public PrintWriter getWriter() {
                    return writer;
                }

        });
        log.debug("Test - " + writer.getCopy());
        writer.close();

Inside the filter class I a开发者_JAVA技巧dded some logging:

12:03:22,404         INFO MyFilter:43 - Before invoking chain
12:03:24,107        DEBUG MyFilter:59 - Test - 
12:03:24,108         INFO MyFilter:73 - After invoking chain

The client side receives HTTP error 503 from this code. And also from the log writer.getCopy() returns an empty string? What could be the reason?

EDIT: Removing the CopyPrintWriter related codes and not overriding getWriter(), the server returns OK with html.

Could be because you are creating a writer , whereas the servlet invocation after filter invocation is writing the content to stream by getting it from HttpServletResponse.getOutputStream().

The error is probably in your MyResponseWrapper class.