android多线程下载-HttpURLConnection

android多线程下载-HttpURLConnection

private static String PATH = "http://192.168.37.2:8080/http/02.jpg";    public static void main(String[] args) throws Exception {        URL url = new URL(PATH);        HttpURLConnection conn = (HttpURLConnection) url.openConnection();        conn.connect();        int totalSize = conn.getContentLength();        int threadCount = 3;        //计算每个字节下载的字节数        int blockSize = totalSize/3;        //资源路径        String path = PATH;        //目标路径        String target = "H://a.jpg";        for (int i = 1; i <= threadCount; i++) {            int id = i;            int startIndex = (id-1)*blockSize;            int endIndex = -1;            if (id==threadCount) {                //3*3-1                endIndex = totalSize-1;            }else {                endIndex = id*blockSize-1;            }            DownloadThread downloadThread = new DownloadThread(id,startIndex,endIndex,path,target);                     downloadThread.start();        }    }    static class DownloadThread extends Thread{        private int id;        private int startIndex;        private int endIndex;        private String path;        private String target;        public DownloadThread(int id, int startIndex, int endIndex,String path, String target) {            super();            this.id = id;            this.startIndex = startIndex;            this.endIndex = endIndex;            this.path = path;            this.target = target;        }        @Override        public void run() {            try {                URL url = new URL(path);                HttpURLConnection conn = (HttpURLConnection) url.openConnection();                conn.setRequestProperty("Range", "bytes="+startIndex+"-"+endIndex);                conn.connect();                int code = conn.getResponseCode();                if (206==code) {                    InputStream inputStream = conn.getInputStream();                    File file = new File(target);                    RandomAccessFile raf = new RandomAccessFile(file ,"rwd");                    raf.seek(startIndex);                    int len=-1;                    byte[] buffer = new byte[1024];                    int total =0;                    while((len=inputStream.read(buffer))!=-1){                        raf.write(buffer,0,len);                        total+=len;                        System.out.println(id+"下载了"+total);                    }                    System.out.println(id+"已完成");                    raf.close();                }            } catch (Exception e) {                e.printStackTrace();            }        }    }