多线程下载及XUtils框架使用

来源：互联网发布：轩辕剑骑兵10进阶数据编辑：程序博客网时间：2024/05/17 06:34

一、多线程下载

1、获取文件大小

/** * 获取要下载的文件大小 * @param urlStr * @return */public static long getFileLength(String urlStr) {HttpURLConnection conn = null;try {URL url = new URL(urlStr);conn = (HttpURLConnection) url.openConnection();conn.setRequestMethod("GET");conn.setConnectTimeout(10 * 1000);conn.setReadTimeout(6 * 1000);conn.connect();int code = conn.getResponseCode();if (code == 200) {//获取下载内容的大小，单位是bytelong contentLength = conn.getContentLength();conn.disconnect();return contentLength;}} catch (Exception e) {e.printStackTrace();} finally {if (conn != null) {conn.disconnect();}}return 0;}

2、主函数

private static int threadCount = 3; //下载的线程数量private static long blockSize; //下载的文件平分每一块的大小public static void main(String[] args) {new Thread() {public void run() {//1，获取要下载的文件大小String urlStr = "http://192.168.0.145//Content/App/DBX_140614_V2.0.apk";long length = getFileLength(urlStr);blockSize = length / threadCount;try {//2，本地创建一个空文件，文件大小和将下载的文件大小一样File file = new File("D:\\test.apk");//使用RandomAccessFile对象来创建。//"rw"为可读写权限，当做多线程断点续传功能是，权限要改为"rwd"，目的是能将中断在硬件缓冲区的数据强刷进硬盘。RandomAccessFile raf = new RandomAccessFile(file, "rw");raf.setLength(length);} catch (Exception e) {e.printStackTrace();}//3，开启多个线程for (int i = 0; i < threadCount; i++) {//计算每个线程下载的开始位置和结束位置long startPosition = i * blockSize;long endPosition = (i + 1) * blockSize - 1;if (i == threadCount - 1) {endPosition = length - 1;}GetDataRunnable getDataRunnable = new GetDataRunnable(urlStr, i, startPosition, endPosition);Thread thread = new Thread(getDataRunnable);thread.start();}};}.start();}

3、每个子线程分别下载对应的内容

private static class GetDataRunnable implements Runnable {private int id;private long startPosition;private long endPosition;private String urlStr;public GetDataRunnable(String urlStr, int id, long startPosition,long endPosition) {this.id = id;this.startPosition = startPosition;this.endPosition = endPosition;this.urlStr = urlStr;}@Overridepublic void run() {HttpURLConnection conn = null;RandomAccessFile raf = null;InputStream is = null;try {URL url = new URL(urlStr);conn = (HttpURLConnection) url.openConnection();conn.setRequestMethod("GET");//设置该线程下载内容的范围conn.setRequestProperty("Range", "bytes=" + startPosition + "-"+ endPosition);conn.setConnectTimeout(10 * 1000);conn.setReadTimeout(6 * 1000);conn.connect();File file = new File("D:\\test.apk");raf = new RandomAccessFile(file, "rw");//把文件的位置指针定位在开始位置raf.seek(startPosition);//conn.getResponseCode() 成功返回码不是200is = conn.getInputStream();int len = -1;byte[] b = new byte[1024];while ((len = is.read(b)) != -1) {//往RandomAccessFile指向的本地文件中写入数据raf.write(b, 0, len);}} catch (Exception e) {e.printStackTrace();} finally {if (raf != null) {try {raf.close();} catch (IOException e) {e.printStackTrace();}}if (is != null) {try {is.close();} catch (IOException e) {e.printStackTrace();}}}}}

二、Xutils框架的HttpUtils类使用

HttpUtils httpUtils = new HttpUtils();httpUtils.download("http://192.168.0.145//Content/App/DBX_140614_V2.0.apk",Environment.getExternalStorageDirectory().getAbsolutePath() + "/XX.zip", true,true, new RequestCallBack<File>() {@Overridepublic void onFailure(HttpException arg0, String arg1) {Log.i("DBXStore", "onFailure:" + arg1);}   @Overridepublic void onSuccess(ResponseInfo<File> arg0) {Log.i("DBXStore", "onSuccess");}});

三、断点续传

断点续传功能其实就是在上面的多线程功能的基础上，增加一个下载字节的保存。每一个while循环都保存一下当前已下载的字节数。以便暂停后继续进行。

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