Servlet 下载文件代码，servlet下载文件,public class

Servlet 下载文件代码，servlet下载文件,public class

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();    }}