HttpURLConnection 远程多线程下载 小demo，,class --MyM

HttpURLConnection 远程多线程下载 小demo，,class --MyM

class  --MyMutilDownpublic class MyMutilDown {/**     * 单线程的远程下载     */    public void testOneTDown(String filePath, String url) {        try {            // 要写入的文件            File file = new File(filePath + getFileExtName(url));            FileWriter fWriter = new FileWriter(file);            URL ul = new URL(url);            URLConnection conn = ul.openConnection();            conn.setConnectTimeout(2000);// 请求超时时间            // int len = conn.getContentLength();            InputStream in = conn.getInputStream();            // byte[] by = new byte[1024];            int temp = 0;            while ((temp = in.read()) != -1) {                fWriter.write(temp);            }            fWriter.close();            in.close();        } catch (MalformedURLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    /**     * 文件后缀名     *      * @param path     * @return     */    public String getFileExtName(String path) {        return path.substring(path.lastIndexOf("."));    }/**     * 测试多线程     *      * @param filePath     *            文件保存路径     * @param url     *            url     * @param tnum     *            线程数量     */    public void testMoreTDown(String filePath, String url, int tnum) {        try {            // 要写入的文件            final File file = new File(filePath + getFileExtName(url));            RandomAccessFile accessFile = new RandomAccessFile(file, "rwd");// 建立随机访问            final URL ul = new URL(url);            HttpURLConnection conn = (HttpURLConnection) ul.openConnection();            conn.setConnectTimeout(2000);// 请求超时时间            conn.setRequestMethod("GET");            int len = conn.getContentLength();// 文件长度            accessFile.setLength(len);            accessFile.close();            final int block = (len + tnum - 1) / tnum;// 每个线程下载的快大小            for (int i = 0; i < tnum; i++) {                final int a = i;                new Thread(new Runnable() {                    int start = block * a;// 开始位置                    int end = block * (a + 1) - 1;// 结束位置                    @Override                    public void run() {                        HttpURLConnection conn2 = null;//http连接                        RandomAccessFile accessFile2 = null;                        InputStream in = null;//从http连接拿到的流                        try {                            conn2 = (HttpURLConnection) ul.openConnection();                            conn2.setConnectTimeout(2000);// 请求超时时间                            conn2.setRequestMethod("GET");                            // TODO Auto-generated method stub                            conn2.setRequestProperty("Range", "bytes=" + start                                    + "-" + end + "");// 设置一般请求属性 范围                            in = conn2.getInputStream();                            byte[] data = new byte[1024];                            int len = 0;                            accessFile2 = new RandomAccessFile(file, "rwd");                            accessFile2.seek(start);                            while ((len = in.read(data)) != -1) {                                accessFile2.write(data, 0, len);                            }                            System.out.println("线程:" + a + "下载完成!");                        } catch (IOException e1) {                            // TODO Auto-generated catch block                            e1.printStackTrace();                        } finally {                            try {                                accessFile2.close();                                in.close();                            } catch (IOException e) {                                // TODO Auto-generated catch block                                e.printStackTrace();                            }                        }                    }                }).start();            }        } catch (MalformedURLException e) {            // TODO Auto-generated catch block            e.printStackTrace();        } catch (IOException e) {            // TODO Auto-generated catch block            e.printStackTrace();        }    }    /**     * @param args     * @throws IOException     */    public static void main(String[] args) throws IOException {        // TODO Auto-generated method stub        MyMutilDown mydown = new MyMutilDown();        String path = "http://static.ishare.down.sina.com.cn/5585234.txt?ssig=f7CrV3UL8%2B&Expires=1347724800&KID=sina,ishare&ip=1347592902,117.40.138.&fn=%E5%8E%9A%E9%BB%91%E5%AD%A6.TXT";        // mydown.downLoad(path, "D:\\\\aa", 1);        // mydown.testOneTDown("D:\\\\", path);        mydown.testMoreTDown("D:\\\\aa", path, 3);    }}//该片段来自于http://byrx.net