著论准过秦，作赋拟子虚。这篇文章主要讲述安卓 多线程下载文件相关的知识，希望能为你提供帮助。
HTTP文件多线程下载
测试代码

String downloadUrl = "http://192.168.31.162/FileServer/SoftApk/UC-11.5.5.943.apk"; String filepath = PathUtils.getCachePath() + "UC-11.5.5.943.apk"; /** * 多线程下载 *基于：http://blog.csdn.net/mad1989/article/details/38421465 * */ private void startMutitaskDownload(){ DownloadTask dlTask = new DownloadTask(downloadUrl, filepath, 5, new DownloadTask.DLListener() { @Override public void onDLStart() {}@Override public void onDLFinished(final long costTime, final long dlSize) { runOnUiThread(new Runnable() { @Override public void run() { DecimalFormat dFormat=newDecimalFormat("##0.00"); Double res = dlSize * 1.0 / 1024 / costTime; String speed = dFormat.format(res); tvDlAverage.setText("平均下载速度：" + speed + "Mb/s "); } }); }@Override public void onProgressChange(final long fileSize, final long dlSize) { runOnUiThread(new Runnable() { @Override public void run() { tvDlInfo.setText("下载速度：" + dlSize / 1024 / 1024 + "Mb/s " + "下载进度：" + dlSize / (fileSize / 100) + "%"); } }); } }); dlTask.start(); }

 

DownloadTask.java

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import java.io.File; import java.net.URL; import java.net.URLConnection; import java.util.Timer; import java.util.TimerTask; import utils.MLog; /** * Created by e2670 on 2017/9/10. * FtpDownloadTask 多线程下载任务分配 */public class DownloadTask extends Thread{ private String downloadUrl; private String filePath; private int threadNum; private long fileSize; private int downloadedAllSize = 0; // 当前所有线程下载总量boolean isFinished = false; public DownloadTask(String downloadUrl, String filePath, int threadNum, DLListener dlListener) { this.downloadUrl = downloadUrl; this.threadNum = threadNum; this.filePath = filePath; this.dlListener = dlListener; }@Override public void run() { final DLThread[] threads = new DLThread[threadNum]; try { URL url = new URL(downloadUrl); MLog.d(downloadUrl); URLConnection conn = url.openConnection(); // 读取下载文件总大小 fileSize = conn.getContentLength(); if (fileSize == -1) { // nginx文件服务器 fileSize = Long.valueOf(conn.getHeaderField("Content-Length")); } if (fileSize < = 0) { MLog.e("读取文件失败:文件大小" + fileSize); return; } // 计算每条线程下载的数据长度 long blockSize = (fileSize % threadNum) == 0 ? fileSize / threadNum : fileSize / threadNum + 1; MLog.d("threadNum:" + threadNum + "fileSize:" + fileSize + "blockSize:" + blockSize); File file = new File(filePath); for (int i = 0; i < threads.length; i++) { // 启动线程，分别下载每个线程需要下载的部分 threads[i] = new DLThread(url, file, blockSize, (i + 1)); threads[i].setName("FtpDLThread:" + i); threads[i].start(); } final long startTime = System.currentTimeMillis(); dlListener.onDLStart(); // 每秒统计一次已下载文件大小 final Timer timer = new Timer(); TimerTask timerTask = new TimerTask() { @Override public void run() { isFinished = true; downloadedAllSize = 0; for (int i = 0; i < threads.length; i++) { downloadedAllSize += threads[i].getDownloadLength(); if (!threads[i].isCompleted()) { isFinished = false; } } dlListener.onProgressChange(fileSize, downloadedAllSize); if(isFinished){ timer.cancel(); dlListener.onDLFinished(System.currentTimeMillis() - startTime,downloadedAllSize); } } }; timer.schedule(timerTask,1000,1000); } catch (Exception e) { e.printStackTrace(); } }private DLListener dlListener; public interface DLListener { void onDLStart(); void onDLFinished(long costTime,long dlSize); void onProgressChange(long fileSize, long dlSize); } }

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DLThread.java

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import java.io.BufferedInputStream; import java.io.File; import java.io.IOException; import java.io.RandomAccessFile; import java.net.URL; import java.net.URLConnection; import utils.MLog; /** * Created by e2670 on 2017/9/10. * FtpDLThread 完成每个独立线程的下载任务 */ public class DLThread extends Thread {private static final String TAG = DLThread.class.getSimpleName(); /** * 当前下载是否完成 */ private boolean isCompleted = false; /** * 当前下载文件长度 */ private long downloadLength = 0; /** * 文件保存路径 */ private File file; /** * 文件下载路径 */ private URL downloadUrl; /** * 当前下载线程ID */ private int threadId; /** * 线程下载数据长度 */ private long blockSize; private int cacheSize = 100 * 1024; /** * @param downloadUrl:文件下载地址 * @param file:文件保存路径 * @param blockSize:下载数据长度 * @param threadId:线程ID */ public DLThread(URL downloadUrl, File file, long blockSize, int threadId) { this.downloadUrl = downloadUrl; this.file = file; this.threadId = threadId; this.blockSize = blockSize; }@Override public void run() { BufferedInputStream bis = null; RandomAccessFile raf = null; try { URLConnection conn = downloadUrl.openConnection(); conn.setAllowUserInteraction(true); long startPos = blockSize * (threadId - 1); //开始位置 long endPos = blockSize * threadId - 1; //结束位置 //设置当前线程下载的起点、终点 conn.setRequestProperty("Range", "bytes=" + startPos + "-" + endPos); MLog.d(Thread.currentThread().getName() + "bytes=" + startPos + "-" + endPos); byte[] buffer = new byte[cacheSize]; bis = new BufferedInputStream(conn.getInputStream()); raf = new RandomAccessFile(file, "rwd"); raf.seek(startPos); int len; while ((len = bis.read(buffer, 0, cacheSize)) != -1) { raf.write(buffer, 0, len); downloadLength += len; } isCompleted = true; MLog.d(TAG, "current thread task has finished,all size:" + downloadLength); } catch (IOException e) { e.printStackTrace(); } finally { if (bis != null) { try { bis.close(); } catch (IOException e) { e.printStackTrace(); } } if (raf != null) { try { raf.close(); } catch (IOException e) { e.printStackTrace(); } } } }/** * 线程文件是否下载完毕 */ public boolean isCompleted() { return isCompleted; }/** * 线程下载文件长度 */ public long getDownloadLength() { return downloadLength; }}

View Code 
FTP文件多线程下载
测试代码

Apache Commons Net 3.6

String downloadUrl = "ftp://[email  protected]/SoftApk/UC-11.5.5.943.apk"; String filepath = PathUtils.getCachePath() + "UC-11.5.5.943.apk"; /** * 多线程下载 *基于：http://blog.csdn.net/qwe511455842/article/details/76603675 * */ private void startMutitaskDownload(){ FtpDownloadTask dlTask = new FtpDownloadTask(downloadUrl, filepath, 5, new FtpDownloadTask.DLListener() { @Override public void onDLStart() {}@Override public void onDLFinished(final long costTime, final long dlSize) { runOnUiThread(new Runnable() { @Override public void run() { DecimalFormat dFormat=newDecimalFormat("##0.00"); Double res = dlSize * 1.0 / 1024 / costTime; String speed = dFormat.format(res); tvDlAverage.setText("平均下载速度：" + speed + "Mb/s "); } }); }@Override public void onProgressChange(final long fileSize, final long dlSize) { runOnUiThread(new Runnable() { @Override public void run() { tvDlInfo.setText("下载速度：" + dlSize / 1024 / 1024 + "Mb/s " + "下载进度：" + dlSize / (fileSize / 100) + "%"); } }); } }); dlTask.start(); }

FtpDownloadTask.java

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import org.apache.commons.net.ftp.FTPClient; import org.apache.commons.net.ftp.FTPFile; import org.apache.commons.net.ftp.FTPReply; import java.io.File; import java.util.Timer; import java.util.TimerTask; import utils.MLog; /** * Created by e2670 on 2017/9/10. * FtpDownloadTask 多线程下载任务分配 */public class FtpDownloadTask extends Thread{ private String downloadUrl; private String filePath; private int threadNum; private long fileSize; private int downloadedAllSize = 0; // 当前所有线程下载总量boolean isFinished = false; public FtpDownloadTask(String downloadUrl, String filePath, int threadNum, DLListener dlListener) { this.downloadUrl = downloadUrl; this.threadNum = threadNum; this.filePath = filePath; this.dlListener = dlListener; }@Override public void run() { final FtpDLThread[] threads = new FtpDLThread[threadNum]; try { MLog.d(downloadUrl); FTPClient client = new FTPClient(); FtpLogin ftpLogin; try { ftpLogin = parseFtpUrl(downloadUrl); }catch (Exception e){ e.printStackTrace(); MLog.e("ftp url解析错误"); return; } client.connect(ftpLogin.ipAddr,ftpLogin.port); if(ftpLogin.userName != null){ client.login(ftpLogin.userName, ftpLogin.password); }int reply = client.getReplyCode(); if (!FTPReply.isPositiveCompletion(reply)) { client.disconnect(); MLog.e("无法连接到ftp服务器，错误码为：" + reply); return; }String charSet = "UTF-8"; if (!FTPReply.isPositiveCompletion(client.sendCommand("OPTS UTF8", "ON"))) { charSet = "GBK"; } FTPFile[] files = client.listFiles(new String(ftpLogin.path.getBytes(charSet), "ISO-8859-1")); if(files.length > 0){ fileSize = files[0].getSize(); }if (fileSize < = 0) { MLog.e("读取文件失败:文件大小" + fileSize); return; } // 计算每条线程下载的数据长度 long blockSize = (fileSize % threadNum) == 0 ? fileSize / threadNum : fileSize / threadNum + 1; MLog.d("threadNum:" + threadNum + "fileSize:" + fileSize + "blockSize:" + blockSize); File file = new File(filePath); for (int i = 0; i < threads.length; i++) { // 启动线程，分别下载每个线程需要下载的部分 threads[i] = new FtpDLThread(ftpLogin, file, blockSize, (i + 1)); threads[i].setName("FtpDLThread:" + i); threads[i].start(); } final long startTime = System.currentTimeMillis(); dlListener.onDLStart(); // 每秒统计一次已下载文件大小 final Timer timer = new Timer(); TimerTask timerTask = new TimerTask() { @Override public void run() { isFinished = true; downloadedAllSize = 0; for (int i = 0; i < threads.length; i++) { downloadedAllSize += threads[i].getDownloadLength(); if (!threads[i].isCompleted()) { isFinished = false; } } dlListener.onProgressChange(fileSize, downloadedAllSize); if(isFinished){ timer.cancel(); dlListener.onDLFinished(System.currentTimeMillis() - startTime,downloadedAllSize); } } }; timer.schedule(timerTask,1000,1000); } catch (Exception e) { e.printStackTrace(); } }/** * FTP url解析 * @param fullUrl * @return */ private FtpLogin parseFtpUrl(String fullUrl) throws Exception{ FtpLogin ftpLogin = new FtpLogin(); fullUrl = fullUrl.trim(); String res; int beginIndex = "ftp://".length(); int endIndex = fullUrl.indexOf(‘/‘, beginIndex); if(endIndex != -1){ res =fullUrl.substring(beginIndex, endIndex); String[] splitRes = res.split("@"); if(splitRes.length > 1){// IP+Login String[] splitIp = splitRes[1].split(":"); ftpLogin.ipAddr = splitIp[0]; if (splitIp.length > 1){ ftpLogin.port = Integer.parseInt(splitIp[1]); }else { ftpLogin.port = 21; } String[] splitUser = splitRes[0].split(":"); ftpLogin.userName = splitUser[0]; if (splitIp.length > 1){ ftpLogin.password = splitUser[1]; }else { ftpLogin.password = ""; } }else { // IP String[] splitIp = splitRes[0].split(":"); ftpLogin.ipAddr = splitIp[0]; if (splitIp.length > 1){ ftpLogin.port = Integer.parseInt(splitIp[1]); }else { ftpLogin.port = 21; } } ftpLogin.path = fullUrl.substring(endIndex); }else { throw new Exception("URL解析错误"); } return ftpLogin; }private DLListener dlListener; public interface DLListener { void onDLStart(); void onDLFinished(long costTime, long dlSize); void onProgressChange(long fileSize, long dlSize); } }

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FtpDLThread.java

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import org.apache.commons.net.ftp.FTP; import org.apache.commons.net.ftp.FTPClient; import org.apache.commons.net.ftp.FTPReply; import java.io.BufferedInputStream; import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.RandomAccessFile; import utils.MLog; /** * Created by e2670 on 2017/9/10. * FtpDLThread 完成每个独立线程的下载任务 */ public class FtpDLThread extends Thread {private static final String TAG = FtpDLThread.class.getSimpleName(); /** * 当前下载是否完成 */ private boolean isCompleted = false; /** * 当前下载文件长度 */ private long downloadLength = 0; /** * 文件保存路径 */ private File file; /** * 文件下载路径 */ private FtpLogin ftpLogin; /** * 当前下载线程ID */ private int threadId; /** * 线程下载数据长度 */ private long blockSize; private int cacheSize = 100 * 1024; /** * @param ftpLogin:文件下载地址 * @param file:文件保存路径 * @param blockSize:下载数据长度 * @param threadId:线程ID */ public FtpDLThread(FtpLogin ftpLogin, File file, long blockSize, int threadId) { this.ftpLogin = ftpLogin; this.file = file; this.threadId = threadId; this.blockSize = blockSize; }@Override public void run() { BufferedInputStream bis = null; RandomAccessFile raf = null; try { FTPClient client = new FTPClient(); client.connect(ftpLogin.ipAddr, ftpLogin.port); if (ftpLogin.userName != null) { client.login(ftpLogin.userName, ftpLogin.password); }client.enterLocalPassiveMode(); //设置被动模式 client.setFileType(FTP.BINARY_FILE_TYPE); //设置文件传输模式 long startPos = blockSize * (threadId - 1); //开始位置 long endPos = blockSize * threadId - 1; //结束位置 client.setRestartOffset(startPos); //设置恢复下载的位置 MLog.d(Thread.currentThread().getName() + "bytes=" + startPos + "-" + endPos); String charSet = "UTF-8"; if (!FTPReply.isPositiveCompletion(client.sendCommand("OPTS UTF8", "ON"))) { charSet = "GBK"; } client.allocate(cacheSize); InputStream is = client.retrieveFileStream(new String(ftpLogin.path.getBytes(charSet), "ISO-8859-1")); int reply = client.getReplyCode(); if (!FTPReply.isPositivePreliminary(reply)) { client.disconnect(); MLog.e("获取文件信息错误，错误码为：" + reply, null); return; }byte[] buffer = new byte[cacheSize]; bis = new BufferedInputStream(is); raf = new RandomAccessFile(file, "rwd"); raf.seek(startPos); int len; while ((len = bis.read(buffer, 0, cacheSize)) != -1) { raf.write(buffer, 0, len); downloadLength += len; if (downloadLength > = endPos - startPos){ break; } } isCompleted = true; MLog.d(TAG, "current thread task has finished,all size:" + downloadLength); } catch (IOException e) { e.printStackTrace(); } finally { if (bis != null) { try { bis.close(); } catch (IOException e) { e.printStackTrace(); } } if (raf != null) { try { raf.close(); } catch (IOException e) { e.printStackTrace(); } } } }/** * 线程文件是否下载完毕 */ public boolean isCompleted() { return isCompleted; }/** * 线程下载文件长度 */ public long getDownloadLength() { return downloadLength; }}

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FtpLogin.java

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public class FtpLogin { public String userName; public String password; public String ipAddr; public int port; public String path; }

View Code【安卓 多线程下载文件】 

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