java多线程批量下载文件

文件长度" + fileLength);

        size = fileLength / threadCount;

        System.out.println("每个下载量==" + size);

        conn.disconnect();// 断开链接

    }

    public URL getFileUrl() {

        return fileUrl;

    public int getThreadCount() {

        return this.threadCount;

    /**

     * 开始下载

     */

    public void startDown() {

        for (int i = 0; i < threadCount; i++) {

            try {

                RandomAccessFile raFile = new RandomAccessFile(pathName, "rw");

                tDownthreads[i] = new Downthread(i * size, raFile, i);

                tDownthreads[i].start();

            } catch (FileNotFoundException e) {

                e.printStackTrace();

            }

        }

     * 下载线程类

     *

     * @author luweicheng

    class Downthread extends Thread {

        private int startPos;// 开始的位置

        private InputStream is;

        private RandomAccessFile raFile;

        private int length;// 下载的文件长度

        private int flag;// 线程标志

        public Downthread(int startPos, RandomAccessFile raFile, int i) {

            this.startPos = startPos;

            this.raFile = raFile;

            flag = i;

        @Override

        public void run() {

                HttpURLConnection connection = (HttpURLConnection) fileUrl.openConnection();

                connection.setRequestMethod("GET");

                connection.setRequestProperty("connection", "keep-alive");

                connection.setConnectTimeout(5 * 1000);

                is = connection.getInputStream();

                is.skip(startPos);

                raFile.seek(startPos);

                byte[] buf = new byte[8 * 1024];

                int hasread = 0;// 读出的字节数

                // 将位置在 startPos - startPos 位置的数据读出写入

                while (length < size && (hasread = is.read(buf)) != -1) {

                    raFile.write(buf, 0, hasread);

                    length += hasread;

                    System.out.println("*****线程" + flag + "下载了*********" + length);

                }

                System.out.println("*******线程" + flag + "下载完成*********");

            } catch (IOException e) {

            } finally {

                try {

                    is.close();

                    raFile.close();

                } catch (IOException e) {

                    e.printStackTrace();

}

 效果展示：