Android之多线程断点下载
来源：互联网 发布：jquery数组长度 编辑：程序博客网 时间：2024/05/01 11:17
本文主要包含多线程下载的一些简单demo,包括三部分
- java实现
- android实现
- XUtils开源库实现
注意下载添加网络权限与SD卡读写权限
java实现多线程下载
public class MutileThreadDownload { /** * 线程的数量 */ private static int threadCount = 3; /** * 每个下载区块的大小 */ private static long blocksize; /** * 正在运行的线程的数量 */ private static int runningThreadCount; /** * @param args * @throws Exception */ public static void main(String[] args) throws Exception { // 服务器文件的路径 String path = "http://192.168.1.100:8080/ff.exe"; URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("GET"); conn.setConnectTimeout(5000); int code = conn.getResponseCode(); if (code == 200) { long size = conn.getContentLength();// 得到服务端返回的文件的大小 System.out.println("服务器文件的大小：" + size); blocksize = size / threadCount; // 1.首先在本地创建一个大小跟服务器一模一样的空白文件。 File file = new File("temp.exe"); RandomAccessFile raf = new RandomAccessFile(file, "rw"); raf.setLength(size); // 2.开启若干个子线程分别去下载对应的资源。 runningThreadCount = threadCount; for (int i = 1; i <= threadCount; i++) { long startIndex = (i - 1) * blocksize; long endIndex = i * blocksize - 1; if (i == threadCount) { // 最后一个线程 endIndex = size - 1; } System.out.println("开启线程：" + i + "下载的位置：" + startIndex + "~" + endIndex); new DownloadThread(path, i, startIndex, endIndex).start(); } } conn.disconnect(); } private static class DownloadThread extends Thread { private int threadId; private long startIndex; private long endIndex; private String path; public DownloadThread(String path, int threadId, long startIndex, long endIndex) { this.path = path; this.threadId = threadId; this.startIndex = startIndex; this.endIndex = endIndex; } @Override public void run() { try { // 当前线程下载的总大小 int total = 0; File positionFile = new File(threadId + ".txt"); URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection) url .openConnection(); conn.setRequestMethod("GET"); // 接着从上一次的位置继续下载数据 if (positionFile.exists() && positionFile.length() > 0) {// 判断是否有记录 FileInputStream fis = new FileInputStream(positionFile); BufferedReader br = new BufferedReader( new InputStreamReader(fis)); // 获取当前线程上次下载的总大小是多少 String lasttotalstr = br.readLine(); int lastTotal = Integer.valueOf(lasttotalstr); System.out.println("上次线程" + threadId + "下载的总大小：" + lastTotal); startIndex += lastTotal; total += lastTotal;// 加上上次下载的总大小。 fis.close(); } conn.setRequestProperty("Range", "bytes=" + startIndex + "-" + endIndex); conn.setConnectTimeout(5000); int code = conn.getResponseCode(); System.out.println("code=" + code); InputStream is = conn.getInputStream(); File file = new File("temp.exe"); RandomAccessFile raf = new RandomAccessFile(file, "rw"); // 指定文件开始写的位置。 raf.seek(startIndex); System.out.println("第" + threadId + "个线程：写文件的开始位置：" + String.valueOf(startIndex)); int len = 0; byte[] buffer = new byte[512]; while ((len = is.read(buffer)) != -1) { RandomAccessFile rf = new RandomAccessFile(positionFile, "rwd"); raf.write(buffer, 0, len); total += len; rf.write(String.valueOf(total).getBytes()); rf.close(); } is.close(); raf.close(); } catch (Exception e) { e.printStackTrace(); } finally { // 只有所有的线程都下载完毕后 才可以删除记录文件。 synchronized (MutileThreadDownload.class) { System.out.println("线程" + threadId + "下载完毕了"); runningThreadCount--; if (runningThreadCount < 1) { System.out.println("所有的线程都工作完毕了。删除临时记录的文件"); for (int i = 1; i <= threadCount; i++) { File f = new File(i + ".txt"); System.out.println(f.delete()); } } } } } }}安卓实现
public class MainActivity extends Activity { protected static final int DOWNLOAD_ERROR = 1; private static final int THREAD_ERROR = 2; public static final int DWONLOAD_FINISH = 3; private EditText et_path; private EditText et_count; /** * 存放进度条的布局 */ private LinearLayout ll_container; /** * 进度条的集合 */ private List<ProgressBar> pbs; /** * android下的消息处理器，在主线程创建，才可以更新ui */ private Handler handler = new Handler(){ public void handleMessage(Message msg) { switch (msg.what) { case DOWNLOAD_ERROR: Toast.makeText(getApplicationContext(), "下载失败", 0).show(); break; case THREAD_ERROR: Toast.makeText(getApplicationContext(), "下载失败,请重试", 0).show(); break; case DWONLOAD_FINISH: Toast.makeText(getApplicationContext(), "下载完成", 0).show(); break; } }; }; /** * 线程的数量 */ private int threadCount = 3; /** * 每个下载区块的大小 */ private long blocksize; /** * 正在运行的线程的数量 */ private int runningThreadCount; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); et_path = (EditText) findViewById(R.id.et_path); et_count = (EditText) findViewById(R.id.et_count); ll_container = (LinearLayout) findViewById(R.id.ll_container); } /** * 下载按钮的点击事件 * @param view */ public void downLoad(View view){ //下载文件的路径 final String path = et_path.getText().toString().trim(); if(TextUtils.isEmpty(path)){ Toast.makeText(this, "对不起下载路径不能为空", 0).show(); return; } String count = et_count.getText().toString().trim(); if(TextUtils.isEmpty(path)){ Toast.makeText(this, "对不起,线程数量不能为空", 0).show(); return; } threadCount = Integer.parseInt(count); //清空掉旧的进度条 ll_container.removeAllViews(); //在界面里面添加count个进度条 pbs = new ArrayList<ProgressBar>(); for(int j=0;j<threadCount;j++){ ProgressBar pb = (ProgressBar) View.inflate(this, R.layout.pb, null); ll_container.addView(pb); pbs.add(pb); } Toast.makeText(this, "开始下载", 0).show(); new Thread(){ public void run() { try { URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection) url.openConnection(); conn.setRequestMethod("GET"); conn.setConnectTimeout(5000); int code = conn.getResponseCode(); if (code == 200) { long size = conn.getContentLength();// 得到服务端返回的文件的大小 System.out.println("服务器文件的大小：" + size); blocksize = size / threadCount; // 1.首先在本地创建一个大小跟服务器一模一样的空白文件。 File file = new File(Environment.getExternalStorageDirectory(),getFileName(path)); RandomAccessFile raf = new RandomAccessFile(file, "rw"); raf.setLength(size); // 2.开启若干个子线程分别去下载对应的资源。 runningThreadCount = threadCount; for (int i = 1; i <= threadCount; i++) { long startIndex = (i - 1) * blocksize; long endIndex = i * blocksize - 1; if (i == threadCount) { // 最后一个线程 endIndex = size - 1; } System.out.println("开启线程：" + i + "下载的位置：" + startIndex + "~" + endIndex); int threadSize = (int) (endIndex - startIndex); pbs.get(i-1).setMax(threadSize); new DownloadThread(path, i, startIndex, endIndex).start(); } } conn.disconnect(); } catch (Exception e) { e.printStackTrace(); Message msg = Message.obtain(); msg.what = DOWNLOAD_ERROR; handler.sendMessage(msg); } }; }.start(); } private class DownloadThread extends Thread { private int threadId; private long startIndex; private long endIndex; private String path; public DownloadThread(String path, int threadId, long startIndex, long endIndex) { this.path = path; this.threadId = threadId; this.startIndex = startIndex; this.endIndex = endIndex; } @Override public void run() { try { // 当前线程下载的总大小 int total = 0; File positionFile = new File(Environment.getExternalStorageDirectory(),getFileName(path)+threadId + ".txt"); URL url = new URL(path); HttpURLConnection conn = (HttpURLConnection) url .openConnection(); conn.setRequestMethod("GET"); // 接着从上一次的位置继续下载数据 if (positionFile.exists() && positionFile.length() > 0) {// 判断是否有记录 FileInputStream fis = new FileInputStream(positionFile); BufferedReader br = new BufferedReader( new InputStreamReader(fis)); // 获取当前线程上次下载的总大小是多少 String lasttotalstr = br.readLine(); int lastTotal = Integer.valueOf(lasttotalstr); System.out.println("上次线程" + threadId + "下载的总大小：" + lastTotal); startIndex += lastTotal; total += lastTotal;// 加上上次下载的总大小。 fis.close(); //存数据库。 //_id path threadid total } conn.setRequestProperty("Range", "bytes=" + startIndex + "-" + endIndex); conn.setConnectTimeout(5000); int code = conn.getResponseCode(); System.out.println("code=" + code); InputStream is = conn.getInputStream(); File file = new File(Environment.getExternalStorageDirectory(),getFileName(path)); RandomAccessFile raf = new RandomAccessFile(file, "rw"); // 指定文件开始写的位置。 raf.seek(startIndex); System.out.println("第" + threadId + "个线程：写文件的开始位置：" + String.valueOf(startIndex)); int len = 0; byte[] buffer = new byte[1024]; while ((len = is.read(buffer)) != -1) { RandomAccessFile rf = new RandomAccessFile(positionFile, "rwd"); raf.write(buffer, 0, len); total += len; rf.write(String.valueOf(total).getBytes()); rf.close(); pbs.get(threadId-1).setProgress(total); } is.close(); raf.close(); } catch (Exception e) { e.printStackTrace(); Message msg = Message.obtain(); msg.what = THREAD_ERROR; handler.sendMessage(msg); } finally { // 只有所有的线程都下载完毕后 才可以删除记录文件。 synchronized (MainActivity.class) { System.out.println("线程" + threadId + "下载完毕了"); runningThreadCount--; if (runningThreadCount < 1) { System.out.println("所有的线程都工作完毕了。删除临时记录的文件"); for (int i = 1; i <= threadCount; i++) { File f = new File(Environment.getExternalStorageDirectory(),getFileName(path)+ i + ".txt"); System.out.println(f.delete()); } Message msg = Message.obtain(); msg.what = DWONLOAD_FINISH; handler.sendMessage(msg); } } } } } //http://192.168.1.100:8080/aa.exe private String getFileName(String path){ int start = path.lastIndexOf("/")+1; return path.substring(start); }}利用XUtils开源框架实现，需要XUtils的jar包
public class MainActivity extends Activity { private EditText et_path; private TextView tv_info; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); et_path = (EditText) findViewById(R.id.et_path); tv_info = (TextView) findViewById(R.id.tv_info); } public void download(View view){ String path = et_path.getText().toString().trim(); if(TextUtils.isEmpty(path)){ Toast.makeText(this, "请输入下载的路径", 0).show(); return; }else{ HttpUtils http = new HttpUtils(); HttpHandler handler = http.download(path, "/sdcard/xxx.zip", true, // 如果目标文件存在，接着未完成的部分继续下载。服务器不支持RANGE时将从新下载。 true, // 如果从请求返回信息中获取到文件名，下载完成后自动重命名。 new RequestCallBack<File>() { @Override public void onStart() { tv_info.setText("conn..."); } @Override public void onLoading(long total, long current, boolean isUploading) { tv_info.setText(current + "/" + total); } @Override public void onSuccess(ResponseInfo<File> responseInfo) { tv_info.setText("downloaded:" + responseInfo.result.getPath()); } @Override public void onFailure(HttpException error, String msg) { tv_info.setText(msg); } }); } }}完成
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