public class PrintImage extends HttpServlet {

	private static final long serialVersionUID = 1L;

       

    /**

     * @see HttpServlet#HttpServlet()

     */

    public PrintImage() {

        super();

        // TODO Auto-generated constructor stub

    }



	/**

	 * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)

	 */

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

		doPost(request, response);

	}



	/**

	 * @throws IOException 

	 * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)

	 */

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException {

		BufferedOutputStream outputStream =null;

		InputStream fileInputStream = null;

		try{

                        //这里没有设置charset=utf-8 是否有关？

			response.setContentType("image/jpeg");

			response.setHeader("Pragma", "No-cache");

			response.setHeader("Cache-Control", "no-cache");

			response.setHeader("Expires", "0");

			response.setDateHeader("Expires", 0);

			

			System.out.println("PrintImage invoked");

			//文件名称是页面传入的  路径是绝对路径 如/home/image/

			File file = new File(SysParamUtil.getParam(SysParamConstants.FILE_UPLOAD_DISK)+ request.getParameter("fileName"));			

			

			if(!file.exists()) {

				fileInputStream = request.getSession().getServletContext().getResourceAsStream("/ext/resources/images/nopic.gif");

			} else {

				fileInputStream = new FileInputStream(file);

			}

			

			BufferedImage bufferedImage = ImageIO.read(fileInputStream);

			outputStream = new BufferedOutputStream(response.getOutputStream());

			JPEGImageEncoder imageEncoder = JPEGCodec.createJPEGEncoder(outputStream);

			JPEGEncodeParam encodeParam = JPEGCodec.getDefaultJPEGEncodeParam(bufferedImage);

			encodeParam.setQuality(1f, true);

			imageEncoder.encode(bufferedImage, encodeParam);

			

			byte[] data = new byte[8192];

			

			int len = -1;

			

			while((len = fileInputStream.read(data, 0, 8192)) != -1) {

				outputStream.write(data, 0, len);

			}

		}catch(Exception ex){

			ex.printStackTrace();

		}finally{

			if(outputStream !=null){

				outputStream.flush();

				outputStream.close();

			}

			if(fileInputStream != null){

				fileInputStream.close();

			}			

		}		

	}

}