【问题标题】:How to pause a Httpurlconnection in android on button click如何在按钮单击时在android中暂停Httpurlconnection
【发布时间】:2018-01-10 16:19:27
【问题描述】:

我是 android 开发的新手,我一直在通过 android 中的 httpurlconnection 发送一个大文件。 我用于通过 httpurlconnection 上传文件的代码是

 try {
    FileInputStream fileInputStream = new FileInputStream(new File(pathToOurFile));

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

    // Allow Inputs & Outputs
    connection.setDoInput(true);
    connection.setDoOutput(true);
    connection.setUseCaches(false);
    connection.setChunkedStreamingMode(1024)

    // Enable POST method
    connection.setRequestMethod("POST");
    connection.setRequestProperty("Connection", "Keep-Alive");
    connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);

    outputStream = new DataOutputStream(connection.getOutputStream());
    outputStream.writeBytes(twoHyphens + boundary + lineEnd);

    // TOKENID
    String token = "anyvalye";
    outputStream.writeBytes("Content-Disposition: form-data; name=\"Token\"" + lineEnd);
    outputStream.writeBytes("Content-Type: text/plain;charset=UTF-8" + lineEnd);
    outputStream.writeBytes("Content-Length: " + token.length() + lineEnd);
    outputStream.writeBytes(lineEnd);
    outputStream.writeBytes(token + lineEnd);
    outputStream.writeBytes(twoHyphens + boundary + lineEnd);

    String connstr = null;
    connstr = "Content-Disposition: form-data; name=\"UploadFile\";filename=\""
            + pathToOurFile + "\"" + lineEnd;

    outputStream.writeBytes(connstr);
    outputStream.writeBytes(lineEnd);

    bytesAvailable = fileInputStream.available();
    bufferSize = Math.min(bytesAvailable, maxBufferSize);
    TotalFileSize=bufferSize;

    System.out.println("Initial Max Size" + bytesAvailable + "");
    buffer = new byte[bufferSize];

    // Read file
    bytesRead = fileInputStream.read(buffer, 0, bufferSize);
    try {
        while (bytesRead > 0) {
            try {
                outputStream.write(buffer, 0, bufferSize);
            } catch (OutOfMemoryError e) {
                e.printStackTrace();
                response = "outofmemoryerror";
                return response;
            }
            bytesAvailable = fileInputStream.available();
            bufferSize = Math.min(bytesAvailable, maxBufferSize);
            bytesRead = fileInputStream.read(buffer, 0, bufferSize);

        }
    } catch (Exception e) {
        e.printStackTrace();
        response = "error";
        return response;
    }
    outputStream.writeBytes(lineEnd);
    outputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);

    // Responses from the server (code and message)
    int serverResponseCode = connection.getResponseCode();
    String serverResponseMessage = connection.getResponseMessage();
    System.out.println("Server Response Code " + " " + serverResponseCode);
    System.out.println("Server Response Message "+ serverResponseMessage);

    if (serverResponseCode == 200) {
        response = "true";
    } else {
        response = "false";
    }

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

    connection.getInputStream();
    //for android InputStream is = connection.getInputStream();
    java.io.InputStream is = connection.getInputStream();

    int ch;
    StringBuffer b = new StringBuffer();
    while((ch = is.read()) != -1 ) {
        b.append((char)ch);
    }

    String responseString = b.toString();
    System.out.println("response string is" + responseString); //Here is the actual output

    outputStream.close();
    outputStream = null;

} catch (Exception ex) {
    // Exception handling
    response = "error";
    System.out.println("Send file Exception" + ex.getMessage() + "");
    ex.printStackTrace();
}
return response;

我知道在下载文件的过程中,我们可以暂停和恢复下载,并且有很多代码可用。我尝试了这些代码,也得到了解决方案。

但是我可以在 Httpurlconnection 中暂停和恢复上传过程吗?如果我的问题很愚蠢,请原谅我,因为我刚开始学习这个概念。任何人都可以在这里帮助我暂停和恢复上传,因为据我所知没有可用的代码。

调试后,我在这段代码中得到了文件上传大小的响应,

bytesRead = fileInputStream.read(buffer, 0, bufferSize);
try {
    while (bytesRead > 0) {
        try {
            outputStream.write(buffer, 0, bufferSize);
        } catch (OutOfMemoryError e) {
            e.printStackTrace();
            response = "outofmemoryerror";
            return response;
        }
        bytesAvailable = fileInputStream.available();
        bufferSize = Math.min(bytesAvailable, maxBufferSize);
        bytesRead = fileInputStream.read(buffer, 0, bufferSize);

    }
} catch (Exception e) {
    e.printStackTrace();
    response = "error";
    return response;
}

希望能得到一些帮助来更新自己。

【问题讨论】:

  • 流暂停/恢复是两个客户端处理Range 标头字段的能力所提供的功能。如果发送方(使其成为服务器或客户端)能够处理发送内容块并且接收方能够处理重构,那么它的工作方式应该非常相似。 Here an expanation on how it works。您也必须调整服务器,以处理部分上传,我认为它不能像下载一样自行完成。
  • @bracco23 是否 urlconnection.setChunkedStreamingMode(1024) 足以将文件作为块从客户端发送到服务器?
  • 它可能是代码的一部分,但您首先必须确保您的服务器能够处理分块发送的文件。此外,您还必须处理以保持已发送块的数量以及要发送的块的数量才能恢复。

标签: java android http-post httpurlconnection


【解决方案1】:
```
 bytesRead = fileInputStream.read(buffer, 0, bufferSize);
            try {
                while (bytesRead > 0) {
                    try {
                        outputStream.write(buffer, 0, bufferSize);
                    } catch (OutOfMemoryError e) {
                        e.printStackTrace();
                        response = "outofmemoryerror";
                        return response;
                    }
                    bytesAvailable = fileInputStream.available();
                    bufferSize = Math.min(bytesAvailable, maxBufferSize);
                    bytesRead = fileInputStream.read(buffer, 0, bufferSize);

                }
            } catch (Exception e) {
                e.printStackTrace();
                response = "error";
                return response;
}
        }
    ```

【讨论】:

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