将字符串写入文本并下载该文本

/**
  * 字节流，传入的字符串，输出文件；服务器不保存文件，不用指定文件路径
  *
  * @param response
  * @param count
  *            传入的字符串
  * @param fileName
  *            要保存的文件名
  * @return success or error
  * @throws Exception
  */
 public static String downStream(HttpServletResponse response, String count,
   String fileName) throws Exception {
  String msg = null;
  try {
   ServletOutputStream ou = response.getOutputStream();
   // 下载文件
   byte bb[] = count.getBytes();//获取内容的字节
   // ByteArrayInputStream把字节数组当作源的输入流
   ByteArrayInputStream fileInputStream = new ByteArrayInputStream(bb);

   response.setContentType("application/x-msdownload;charset=UTF-8");// 弹出下载的框
   int filelen = fileInputStream.available();
   response.setContentLength(filelen);// 下载统计文件大小的进度
   response.setHeader("Content-Disposition", "attachment; filename="
     + new String(fileName.getBytes(), "ISO-8859-1")); // 设置响应头和下载保存的文件名

   // response.setContentType("application/octet-stream;charset=UTF-8");
   // 下载框的信息
   if (fileInputStream != null) {
    // 文件太大时内存不能一次读出,要循环

    byte a[] = new byte[1024];
    int n = 0;
    while (n != -1) {
     n = fileInputStream.read(a);
     if (n > 0) {
      ou.write(a, 0, n);
     }
    }
   }

   fileInputStream.close();
   ou.close();

   msg = "success";
  } catch (Exception e) {
   e.printStackTrace();
   msg = "error";

  }
  return msg;
 }

/**
  * 写入文本
  *
  * @param path
  *            如：d:/file/
  * @param content
  * @param fileName
  *            如：data.text
  * @return success or error
  */
 public static String writeFile(String path, String fileName, String content) {
  try {
   File pah = new File(path);
   File file = new File(path + "\" + fileName);
   if (!pah.exists()) {
    pah.mkdirs();
    file.createNewFile();
   }
   FileWriter write = new FileWriter(file);
   PrintWriter print = new PrintWriter(write);
   print.write(content);
   write.close();
   print.close();
   return "success";
  } catch (Exception e) {
   e.printStackTrace();
   return "error";
  }

 }