Android：在Cloudinary中上传照片，并在HttpURLConnection中进行进度回调 [英] Android: Uploading a photo in Cloudinary with progress callback in HttpURLConnection
问题描述
我正在尝试修改cloudinary的开源库，以便可以听照片上传的进度。库类包含一个MultipartUtility java类，我对其进行了修改以侦听上传进度。
I'm trying to modify the open source library of cloudinary so that I can listen to the progress of the upload of my photo. The library class contains a MultipartUtility java class that I modified to listen to the progress of the upload.
修改前的原始代码可以在github上找到： https://github.com。 com / cloudinary / cloudinary_java / blob / master / cloudinary-android / src / main / java / com / cloudinary / android / MultipartUtility.java
The original code before modifications can be found on github: https://github.com/cloudinary/cloudinary_java/blob/master/cloudinary-android/src/main/java/com/cloudinary/android/MultipartUtility.java
我从字面上看对其进行了修改，使其类似于来自另一个云服务CloudFS的代码，该文件支持上传文件/图像等时的进度：
I literally modified it to resemble the code from another cloud service CloudFS that supports progress when uploading files / images etc:
package com.cloudinary.android;
import com.cloudinary.Cloudinary;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.Map;
/**
* This utility class provides an abstraction layer for sending multipart HTTP
* POST requests to a web server.
*
* @author www.codejava.net
* @author Cloudinary
*/
public class MultipartUtility {
private final String boundary;
private static final String LINE_FEED = "\r\n";
private static final String APPLICATION_OCTET_STREAM = "application/octet-stream";
private HttpURLConnection httpConn;
private String charset;
private OutputStream outputStream;
private PrintWriter writer;
UploadingCallback uploadingCallback;
public final static String USER_AGENT = "CloudinaryAndroid/" + Cloudinary.VERSION;
Long filesize;
public void setUploadingCallback(UploadingCallback uploadingCallback) {
this.uploadingCallback = uploadingCallback;
}
/**
* This constructor initializes a new HTTP POST request with content type is
* set to multipart/form-data
*
* @param requestURL
* @param charset
* @throws IOException
*/
public MultipartUtility(String requestURL, String charset, String boundary, Map<String, String> headers, Long filesize) throws IOException {
this.charset = charset;
this.boundary = boundary;
this.filesize = filesize;
URL url = new URL(requestURL);
httpConn = (HttpURLConnection) url.openConnection();
httpConn.setDoOutput(true); // indicates POST method
httpConn.setDoInput(true);
httpConn.setFixedLengthStreamingMode(filesize); //added this in
if (headers != null) {
for (Map.Entry<String, String> header : headers.entrySet()) {
httpConn.setRequestProperty(header.getKey(), header.getValue());
}
}
httpConn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
httpConn.setRequestProperty("User-Agent", USER_AGENT);
outputStream = httpConn.getOutputStream();
writer = new PrintWriter(new OutputStreamWriter(outputStream, charset), true);
}
public MultipartUtility(String requestURL, String charset, String boundary) throws IOException {
this(requestURL, charset, boundary, null, 0L);
}
/**
* Adds a form field to the request
*
* @param name field name
* @param value field value
*/
public void addFormField(String name, String value) {
writer.append("--" + boundary).append(LINE_FEED);
writer.append("Content-Disposition: form-data; name=\"" + name + "\"").append(LINE_FEED);
writer.append("Content-Type: text/plain; charset=" + charset).append(LINE_FEED);
writer.append(LINE_FEED);
writer.append(value).append(LINE_FEED);
writer.flush();
}
/**
* Adds a upload file section to the request
*
* @param fieldName name attribute in {@code <input type="file" name="..." />}
* @param uploadFile a File to be uploaded
* @throws IOException
*/
public void addFilePart(String fieldName, File uploadFile, String fileName) throws IOException {
if (fileName == null) fileName = uploadFile.getName();
FileInputStream inputStream = new FileInputStream(uploadFile);
addFilePart(fieldName, inputStream, fileName);
}
public void addFilePart(String fieldName, File uploadFile) throws IOException {
addFilePart(fieldName, uploadFile, "file");
}
public void addFilePart(String fieldName, InputStream inputStream, String fileName) throws IOException {
if (fileName == null) fileName = "file";
writer.append("--" + boundary).append(LINE_FEED);
writer.append("Content-Disposition: form-data; name=\"" + fieldName + "\"; filename=\"" + fileName + "\"").append(LINE_FEED);
writer.append("Content-Type: ").append(APPLICATION_OCTET_STREAM).append(LINE_FEED);
writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
writer.append(LINE_FEED);
writer.flush();
int progress = 0;
byte[] buffer = new byte[4096];
int bytesRead = -1;
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
progress += bytesRead;
/* int percentage = ((progress / filesize.intValue()) * 100);*/
if (uploadingCallback != null) {
uploadingCallback.uploadListener(progress);
}
}
outputStream.flush();
writer.flush();
uploadingCallback = null;
inputStream.close();
writer.append(LINE_FEED);
writer.flush();
}
public void addFilePart(String fieldName, InputStream inputStream) throws IOException {
addFilePart(fieldName, inputStream, "file");
}
/**
* Completes the request and receives response from the server.
*
* @return a list of Strings as response in case the server returned status
* OK, otherwise an exception is thrown.
* @throws IOException
*/
public HttpURLConnection execute() throws IOException {
writer.append("--" + boundary + "--").append(LINE_FEED);
writer.close();
return httpConn;
}
}
我所做的更改是添加关于此线程所建议的httpURLConnection的以下内容：在android中实现文件上传进度栏： httpConn.setFixedLengthStreamingMode（filesize）;
The changes I made were to add on the following to the httpURLConnection as recommended by this thread: How to implement file upload progress bar in android: httpConn.setFixedLengthStreamingMode(filesize);
然后我创建了一个简单的界面来监听上传进度：
I then created a simple interface to listen for the upload progress:
public interface UploadingCallback {
void uploadListener(int progress);
}
然后我在HttpURLConnection编写照片时附加了它：
And then I attached it while the HttpURLConnection wrote the photo:
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
progress += bytesRead;
/* int percentage = ((progress / filesize.intValue()) * 100);*/
if (uploadingCallback != null) {
uploadingCallback.uploadListener(progress);
}
}
代码已经运行，但是上载似乎无法正确测量。该照片约为365kb，上传时间大约为十分之一秒（我从17：56：55.481开始上传，并于17：56：55.554开始上传，那仅是0.7秒多一点）。我不认为我的互联网连接速度如此之快，并且期望至少花费5秒钟。我觉得它正在衡量将照片写入缓冲区所花费的时间，而不是将其发送到cloudinary服务器所花费的时间。
The code ran but the progress of the upload doesn't seem to be measured correctly. The photo was about 365kb and the upload took about a 10th of a second (I started the upload at 17:56:55.481 and by 17:56:55.554 it was done, thats is just over 0.7 seconds). I do not believe my internet connection is that fast and expect it to take at least 5 seconds. I have a feeling it is measuring the time it took to write the photo to the buffer instead of the time it took to send it to cloudinary's servers.
如何获取上传照片所需的时间，以便可以将数据用于进度条？
How can I get it to measure the time it takes to upload the photo so that I can use the data for my progress bar?
04-24 17:56:55.481 28306-28725/com.a upload 4096
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04-24 17:56:55.510 28306-28725/com.a upload 151552
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04-24 17:56:55.514 28306-28725/com.a upload 159744
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04-24 17:56:55.520 28306-28725/com.a upload 204800
04-24 17:56:55.525 28306-28725/com.a upload 208896
04-24 17:56:55.526 28306-28725/com.a upload 212992
04-24 17:56:55.527 28306-28725/com.a upload 217088
04-24 17:56:55.530 28306-28725/com.a upload 221184
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04-24 17:56:55.530 28306-28725/com.a upload 233472
04-24 17:56:55.530 28306-28725/com.a upload 237568
04-24 17:56:55.531 28306-28725/com.a upload 241664
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04-24 17:56:55.545 28306-28725/com.a upload 290816
04-24 17:56:55.545 28306-28725/com.a upload 294912
04-24 17:56:55.547 28306-28725/com.a upload 299008
04-24 17:56:55.547 28306-28725/com.a upload 303104
04-24 17:56:55.547 28306-28725/com.a upload 307200
04-24 17:56:55.547 28306-28725/com.a upload 311296
04-24 17:56:55.547 28306-28725/com.a upload 315392
04-24 17:56:55.548 28306-28725/com.a upload 319488
04-24 17:56:55.548 28306-28725/com.a upload 323584
04-24 17:56:55.548 28306-28725/com.a upload 327680
04-24 17:56:55.548 28306-28725/com.a upload 331776
04-24 17:56:55.549 28306-28725/com.a upload 335872
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04-24 17:56:55.554 28306-28725/com.a upload 365790
要自己进行测试，您需要在cloudinary网站上创建一个免费帐户，以获得您的 cloudname ，以便将Android SDK连接到他们的服务，用于将未签名的内容直接从android直接上传到他们的服务器。
To test this out for yourself, you will need to create a free account on cloudinary website in order to get your cloudname so you can connect your Android SDK to their services for an unsigned direct upload from android directly to their servers.
编辑：
这是我尝试过的方法，当上传实际上在7秒内完成时，它仍在0.7秒内从0-100％跳了起来：
This is what I have tried and it still jumps from 0 - 100% in 0.7 seconds when the upload actually finishes in 7 seconds time:
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
progress += bytesRead;
Log.d("MultiPart", "file transferred so far: "
+ progress);
if (uploadingCallback != null) {
uploadingCallback.uploadListener(progress);
}
Log.d("Flushing", "flush the writer");
outputStream.flush();
writer.flush();
}
推荐答案
正如每次读取部分图片时从代码中看到的那样，您可以编写它到输出缓冲区，但这并不意味着它已发送到服务器，它可能会被缓冲，然后在以后写入服务器。
As you can see from your code every time you read part of the picture, you write it to the output buffer, but that does not mean it's sent to the server, it might be buffered, and then later on write'n to the server.
您有两个选择，要么在每个outputStream.write（）之后调用outputStream.flush（），但这会破坏上传的性能，因为您会失去缓冲的好处。
You have two options, either call outputStream.flush() after every outputStream.write(), but that will kill the performance of the upload, because you would lose the benefits of buffering.
或者您可以在方法末尾的outputStream.flush（）之后调用updateCallback（）。因为在outputStream.flush（）之后，您可以确定数据在服务器上，并且进度已经结束。
Or you could call your updateCallback() after the outputStream.flush() at the end of your method. Because after outputStream.flush() you are certain that the data is on the server, and that progress is over.
有关冲洗的更多信息，请参见此线程 Java流中flush（）的目的是什么？
For more info about the flush see this thread What is the purpose of flush() in Java streams?
这篇关于Android：在Cloudinary中上传照片，并在HttpURLConnection中进行进度回调的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
