Java实现文件下载方法

 public static int downloadFile(String filePath, HttpServletResponse response)
  {
    String fileName = "";
    try
    {
      if (filePath.lastIndexOf("/") > 0)
        fileName = new String(filePath.substring(filePath.lastIndexOf("/") + 1, filePath.length()).getBytes("GB2312"), "ISO8859_1");
      else if (filePath.lastIndexOf("\\") > 0)
        fileName = new String(filePath.substring(filePath.lastIndexOf("\\") + 1, filePath.length()).getBytes("GB2312"), "ISO8859_1");
    }
    catch (Exception localException1) {
    }
    FileInputStream fs = null;
    try {
      fs = new FileInputStream(new File(filePath));
    } catch (FileNotFoundException e) {
      e.printStackTrace();
      int zhuangtai = 1;
      return zhuangtai; } 
response.setContentType("APPLICATION/OCTET-STREAM");
    response.setHeader("Content-Disposition", "attachment; filename=\"" + fileName + "\"");

    int b = 0;
    int zhuangtai;
    try { PrintWriter out = response.getWriter();
      while ((b = fs.read()) != -1) {
        out.write(b);
      }
      fs.close();
      out.close();