这个答案通过向 OutputStreamProgress.java 类添加一个简单的侦听器而不是公共 getProgress() 方法来扩展 kilaka 的答案（老实说，我不确定你应该如何调用 getProgress() 方法，因为线程将在您可能想要调用 getProgress() 的整个过程中一直在 httpclient 的代码中执行！）。
请注意，您需要为要使用的每种实体类型扩展实体类，并且在编写 HttpClient 代码时，您需要创建该新类型的实体。
我编写了一个非常基本的写监听器，它实现了 WriteListener 接口。在这里，您将添加逻辑以对来自 OutputStreamProgress 的写入报告执行某些操作，例如更新进度条 :)
非常感谢 kilaka 使用装饰器的想法潜入计数外流。
WriteLisener.java
public interface WriteListener {
void registerWrite(long amountOfBytesWritten);
}
OutputStreamProgress.java
import java.io.IOException;
import java.io.OutputStream;
public class OutputStreamProgress extends OutputStream {
private final OutputStream outstream;
private long bytesWritten=0;
private final WriteListener writeListener;
public OutputStreamProgress(OutputStream outstream, WriteListener writeListener) {
this.outstream = outstream;
this.writeListener = writeListener;
}
@Override
public void write(int b) throws IOException {
outstream.write(b);
bytesWritten++;
writeListener.registerWrite(bytesWritten);
}
@Override
public void write(byte[] b) throws IOException {
outstream.write(b);
bytesWritten += b.length;
writeListener.registerWrite(bytesWritten);
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
outstream.write(b, off, len);
bytesWritten += len;
writeListener.registerWrite(bytesWritten);
}
@Override
public void flush() throws IOException {
outstream.flush();
}
@Override
public void close() throws IOException {
outstream.close();
}
}
BasicWriteListener
public class BasicWriteListener implements WriteListener {
public BasicWriteListener() {
// TODO Auto-generated constructor stub
}
public void registerWrite(long amountOfBytesWritten) {
System.out.println(amountOfBytesWritten);
}
}
MultipartEntityWithProgressBar
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.Charset;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntity;
public class MultipartEntityWithProgressBar extends MultipartEntity {
private OutputStreamProgress outstream;
private WriteListener writeListener;
@Override
public void writeTo(OutputStream outstream) throws IOException {
this.outstream = new OutputStreamProgress(outstream, writeListener);
super.writeTo(this.outstream);
}
public MultipartEntityWithProgressBar(WriteListener writeListener)
{
super();
this.writeListener = writeListener;
}
public MultipartEntityWithProgressBar(HttpMultipartMode mode, WriteListener writeListener)
{
super(mode);
this.writeListener = writeListener;
}
public MultipartEntityWithProgressBar(HttpMultipartMode mode, String boundary, Charset charset, WriteListener writeListener)
{
super(mode, boundary, charset);
this.writeListener = writeListener;
}
// Left in for clarity to show where I took from kilaka's answer
// /**
// * Progress: 0-100
// */
// public int getProgress() {
// if (outstream == null) {
// return 0;
// }
// long contentLength = getContentLength();
// if (contentLength <= 0) { // Prevent division by zero and negative values
// return 0;
// }
// long writtenLength = outstream.getWrittenLength();
// return (int) (100*writtenLength/contentLength);
// }
}