从String 转换成inputStream最后保存在文件中

String tContent = tDoc.getRootElement().getChildText("Body");
      tInputStream = new   ByteArrayInputStream(tContent.getBytes("GBK"));

String fileDir =  cBankCode+"_" + cComCode+"_" + YBTFun.replaceChar(PubFun.getCurrentDate(), "-", "")+"_OFF_RET";
   
   File f = new File(cFTPDir+fileDir);
      fos = new FileOutputStream(f);
   byte[] b = new byte[1];
   while (tInputStream.read(b) != -1) {
    fos.write(b);
   }