Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.io.FileOutputStream;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.ByteBuffer;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;

public class Main implements ProgressCallBack {
    public static void main(String[] args) {
        new Main("c:/a/data.dat", "http://your server.com/index.htm");
    }

    public Main(String localPath, String remoteURL) {
        FileOutputStream fos;
        ReadableByteChannel rbc;
        URL url;
        try {
            url = new URL(remoteURL);
            rbc = new CallbackByteChannel(Channels.newChannel(url.openStream()), contentLength(url), this);
            fos = new FileOutputStream(localPath);
            fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void callback(CallbackByteChannel rbc, double progress) {
        System.out.println(rbc.getReadSoFar());
        System.out.println(progress);
    }

    int contentLength(URL url) {
        HttpURLConnection connection;
        int contentLength = -1;
        try {
            connection = (HttpURLConnection) url.openConnection();
            contentLength = connection.getContentLength();
        } catch (Exception e) {
        }
        return contentLength;
    }
}

interface ProgressCallBack {
    public void callback(CallbackByteChannel rbc, double progress);
}

class CallbackByteChannel implements ReadableByteChannel {
    ProgressCallBack delegate;
    long size;
    ReadableByteChannel rbc;
    long sizeRead;

    CallbackByteChannel(ReadableByteChannel rbc, long expectedSize, ProgressCallBack delegate) {
        this.delegate = delegate;
        this.size = expectedSize;
        this.rbc = rbc;
    }

    public void close() throws IOException {
        rbc.close();
    }

    public long getReadSoFar() {
        return sizeRead;
    }

    public boolean isOpen() {
        return rbc.isOpen();
    }

    public int read(ByteBuffer bb) throws IOException {
        int n;
        double progress;
        if ((n = rbc.read(bb)) > 0) {
            sizeRead += n;
            progress = size > 0 ? (double) sizeRead / (double) size * 100.0 : -1.0;
            delegate.callback(this, progress);
        }
        return n;
    }
}