android 从web服务器下载word文件，在模拟器可以正常打开，在设备端提示文件损坏是如何一回事

public int downFile(String serverPath, String clientPath, String fileName){
        InputStream inputStream = null;
        try{
          String encodeFileName = URLEncoder.encode(fileName, "UTF-8");
          String serverFilePath = serverPath +"/"+ encodeFileName;
    //      String gbkFilePath = URLEncoder.encode(serverFilePath, "UTF-8");
            FileUtils fileUtils = new FileUtils();
            //测试路径和文件是都存在
            if(fileUtils.isFileExist(serverFilePath)){
                return 1;
            }else{
                inputStream = getInputStreamFromUrl(serverFilePath);
                File resultFile = fileUtils.write2SDFormInput(clientPath, fileName, inputStream);
                if(resultFile == null){
                    return -1;
                }
            }
        }catch (Exception e) {
            e.printStackTrace();
            return -1;
        }finally{
            try{
                inputStream.close();
            }catch (Exception e) {
                e.printStackTrace();
            }
        }
        
        return 0;
    }
    /**
     * 根据URL的到输入流
     * @param urlStr
     * @return
     * @throws MalformedURLException
     * @throws IOException
     */
    public InputStream getInputStreamFromUrl(String urlStr) 
           throws MalformedURLException, IOException{
        url = new URL(urlStr);
        HttpURLConnection urlConn = (HttpURLConnection)url.openConnection();
        InputStream inputStream = urlConn.getInputStream();
        return inputStream;
    }