解决getOutputStream() has already been called for this response

我是在TagSupport中使用了

response.getOutputStream()，导致的这个异常，参考http://gqsunrise.iteye.com/blog/1935758，解决方案如下，添加代码：pageContext.getOut().clear()

        HttpServletResponse response = (HttpServletResponse)pageContext.getResponse();

        response.setHeader("Content-disposition", "attachment;filename="+fileName+"."+fileExt);

        File file = new File(fileURI);

        try {

            FileInputStream fileInputStream = new FileInputStream(file);

            BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);

            ServletOutputStream servletOutputStream = response.getOutputStream();

            BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(servletOutputStream);

            byte[] buffer = new byte[2048];

            int bytesRead;

            while ((bytesRead=bufferedInputStream.read(buffer,0,buffer.length))!=-1) {

                bufferedOutputStream.write(buffer,0,bytesRead);

            }

            bufferedOutputStream.flush();

            pageContext.getOut().clear(); if (bufferedInputStream!=null) {

                bufferedInputStream.close();

            }

            if (bufferedOutputStream!=null) {

                bufferedOutputStream.close();

            }

        } catch (FileNotFoundException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }