Java 代码获取 运营在列表中下载视频的进度 代码

以下是一个简单的Java代码示例，用于获取运营在列表中下载视频的进度：

import java.io.File;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class VideoDownloader {
    private static final int THREAD_POOL_SIZE = 5; // 线程池大小
    private static final int BUFFER_SIZE = 1024 * 1024; // 缓冲区大小
    private static final String SAVE_PATH = "D:/videos/"; // 视频保存路径

    private List<Video> videoList; // 视频列表
    private ExecutorService threadPool; // 线程池
    private int totalSize; // 视频总大小
    private int downloadedSize; // 已下载的视频大小

    public VideoDownloader(List<Video> videoList) {
        this.videoList = videoList;
        threadPool = Executors.newFixedThreadPool(THREAD_POOL_SIZE);
    }

    public void start() {
        // 计算视频总大小
        totalSize = 0;
        for (Video video : videoList) {
            totalSize += video.getSize();
        }

        // 创建本地保存目录
        File saveDir = new File(SAVE_PATH);
        if (!saveDir.exists()) {
            saveDir.mkdirs();
        }

        // 下载视频
        downloadedSize = 0;
        for (Video video : videoList) {
            threadPool.execute(new DownloadTask(video));
        }
    }

    public synchronized int getProgress() {
        return (int) (downloadedSize * 100.0 / totalSize);
    }

    private class DownloadTask implements Runnable {
        private Video video;

        public DownloadTask(Video video) {
            this.video = video;
        }

        @Override
        public void run() {
            try {
                URL url = new URL(video.getUrl());
                HttpURLConnection conn = (HttpURLConnection) url.openConnection();
                conn.setRequestMethod("GET");
                conn.setConnectTimeout(5000);

                // 设置下载区间
                int startPos = video.getStartPos();
                int endPos = video.getEndPos();
                conn.setRequestProperty("Range", "bytes=" + startPos + "-" + endPos);

                // 获取视频输入流
                InputStream is = conn.getInputStream();

                // 创建本地文件
                File file = new File(SAVE_PATH + video.getName());
                RandomAccessFile raf = new RandomAccessFile(file, "rwd");

                // 设置文件写入位置
                raf.seek(startPos);

                // 缓冲区
                byte[] buffer = new byte[BUFFER_SIZE];
                int len;

                // 下载视频数据
                while ((len = is.read(buffer)) != -1) {
                    raf.write(buffer, 0, len);
                    downloadedSize += len;
                }

                // 关闭流
                is.close();
                raf.close();
                conn.disconnect();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    public static void main(String[] args) {
        // 创建视频列表
        List<Video> videoList = new ArrayList<>();
        videoList.add(new Video("video1.mp4", "http://example.com/video1.mp4", 0, 102400));
        videoList.add(new Video("video2.mp4", "http://example.com/video2.mp4", 102401, 204800));
        videoList.add(new Video("video3.mp4", "http://example.com/video3.mp4", 204801, 307200));
        videoList.add(new Video("video4.mp4", "http://example.com/video4.mp4", 307201, 409600));
        videoList.add(new Video("video5.mp4", "http://example.com/video5.mp4", 409601, 512000));

        // 开始下载视频
        VideoDownloader downloader = new VideoDownloader(videoList);
        downloader.start();

        // 显示下载进度
        while (downloader.getProgress() < 100) {
            System.out.printf("Download progress: %d%%\n", downloader.getProgress());
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        System.out.println("Download complete!");
    }
}

class Video {
    private String name;
    private String url;
    private int startPos;
    private int endPos;

    public Video(String name, String url, int startPos, int endPos) {
        this.name = name;
        this.url = url;
        this.startPos = startPos;
        this.endPos = endPos;
    }

    public String getName() {
        return name;
    }

    public String getUrl() {
        return url;
    }

    public int getStartPos() {
        return startPos;
    }

    public int getEndPos() {
        return endPos;
    }

    public int getSize() {
        return endPos - startPos + 1;
    }
}

在上面的代码中，我们使用了Java中的多线程技术来实现视频的并行下载。在主线程中创建了一个线程池，用于管理下载视频的线程。对于每个视频，我们创建了一个下载线程，并将其加入线程池中。在下载线程中，我们使用Java中的URLConnection类打开视频的URL连接，获取视频的大小，并使用Java中的RandomAccessFile类创建一个本地文件，用于存储下载的视频数据。最后，我们在主线程中定时获取线程池中每个下载线程的下载进度，并计算出整个列表的下载进度，并将下载进度显示给用户。