上传文件的块Android

Question

我从here复制了以下代码，我试图上传文件的块来监视进度，是否正确刷新流，如下面的代码所示，并将其用作一个进展？我想咨询一下该代码是由明星

public String multipartRequest(String urlTo, Map httpPara, String filepath, String filefield) throws ParseException, IOException { 
     HttpURLConnection connection = null; 
     DataOutputStream outputStream = null; 
     InputStream inputStream = null; 

     String twoHyphens = "--"; 
     String boundary = "*****"+Long.toString(System.currentTimeMillis())+"*****"; 
     String lineEnd = "\r\n"; 

     String result = ""; 
     int bytesRead, bytesAvailable, bufferSize; 
     byte[] buffer; 
     int maxBufferSize = 1*1024*1024; 

     String[] q = filepath.split("/"); 
     int idx = q.length - 1; 

     try { 
       File file = new File(filepath); 
       FileInputStream fileInputStream = new FileInputStream(file); 

       URL url = new URL(urlTo); 
       connection = (HttpURLConnection) url.openConnection(); 

       connection.setDoInput(true); 
       connection.setDoOutput(true); 
       connection.setUseCaches(false); 

       connection.setRequestMethod("POST"); 
       connection.setRequestProperty("Connection", "Keep-Alive"); 
       connection.setRequestProperty("User-Agent", "Android Multipart HTTP Client 1.0"); 
       connection.setRequestProperty("Content-Type", "multipart/form-data; boundary="+boundary); 
       outputStream = new DataOutputStream(connection.getOutputStream()); 
       outputStream.writeBytes(twoHyphens + boundary + lineEnd); 
       outputStream.writeBytes("Content-Disposition: form-data; name=\"" + filefield + "\"; filename=\"" + q[idx] +"\"" + lineEnd); 
       outputStream.writeBytes("Content-Type: " + getMimeType(filepath) + lineEnd); 
       outputStream.writeBytes("Content-Transfer-Encoding: binary" + lineEnd); 
       outputStream.writeBytes(lineEnd); 

       bytesAvailable = fileInputStream.available(); 
       bufferSize = Math.min(bytesAvailable, maxBufferSize); 
       buffer = new byte[bufferSize]; 

       bytesRead = fileInputStream.read(buffer, 0, bufferSize); 
       while(bytesRead > 0) { 
         outputStream.write(buffer, 0, bufferSize); 
         bytesAvailable = fileInputStream.available(); 
         bufferSize = Math.min(bytesAvailable, maxBufferSize); 
         bytesRead = fileInputStream.read(buffer, 0, bufferSize); 
     ///////////***********************///////////// 
     **********  outputStream.flush(); ********* 
     ///////////***********************///////////// 
       } 

       outputStream.writeBytes(lineEnd); 


       Iterator iter = httpPara.entrySet().iterator(); 

       while (iter.hasNext()) { 
        Map.Entry para = (Map.Entry) iter.next(); 
        outputStream.writeBytes(twoHyphens + boundary + lineEnd); 
        outputStream.writeBytes("Content-Disposition: form-data; name=\"" + para.getKey().toString() + "\"" + lineEnd); 
        outputStream.writeBytes("Content-Type: text/plain"+lineEnd); 
        outputStream.writeBytes(lineEnd); 
        outputStream.writeBytes(para.getValue().toString()); 
        outputStream.writeBytes(lineEnd); 

       } 
       outputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd); 
       inputStream = connection.getInputStream(); 
       result = this.convertStreamToString(inputStream); 

       fileInputStream.close(); 
       inputStream.close(); 
       outputStream.flush(); 
       outputStream.close(); 

       return result; 
     } catch(Exception e) { 
       Log.e("MultipartRequest","Multipart Form Upload Error"); 
       e.printStackTrace(); 
       return null; 
     } 
} 

Answer 1

你可以叫flush()在DataOutputStream类的任何时间包围，没有任何限制。它将自动在底层连接上调用flush，因此您的服务器应该立即收到数据查询，您可以将其用作进度更新。

见here for additional参考

The flush method of DataOutputStream calls the flush method of its underlying output stream.