Servlet 下載文件代碼

public class DownloadServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;


private static final int BUFSIZE = 4096;
String filePath = null;

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

    filePath = getServletContext().getRealPath("") + File.separator + "abc.txt";

    File file = new File(filePath);
    int length = 0;
    ServletOutputStream outStream = response.getOutputStream();
    response.setContentType("text/html");
    response.setContentLength((int) file.length());
    String fileName = (new File(filePath)).getName();
    response.setHeader("Content-Disposition", "attachment; filename=\""+ fileName + "\"");

    byte[] byteBuffer = new byte[BUFSIZE];
    DataInputStream in = new DataInputStream(new FileInputStream(file));

    while ((in != null) && ((length = in.read(byteBuffer)) != -1)) {
        outStream.write(byteBuffer, 0, length);
    }

    in.close();
    outStream.close();
}


}</pre>