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多线程下载文件

来源:程序员人生   发布时间:2016-07-04 09:01:23 阅读次数:2197次

多线程下载文件

DBOpenHelper.java

package com.amlapp.update.otaupgrade.download; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper; public class DBOpenHelper extends SQLiteOpenHelper { // 数据库文件的文件名 private static final String DBNAME = "download.db"; // 数据库的版本号 private static final int VERSION = 1; public DBOpenHelper(Context context) { super(context, DBNAME, null, VERSION); } @Override public void onCreate(SQLiteDatabase db) { db.execSQL("CREATE TABLE IF NOT EXISTS filedownlog (id integer primary key autoincrement, downpath varchar(100), threadid INTEGER, downlength INTEGER)"); } @Override public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { db.execSQL("DROP TABLE IF EXISTS filedownlog"); onCreate(db); } }

DownloadThread.java

package com.amlapp.update.otaupgrade.download; import java.io.BufferedInputStream; import java.io.File; import java.io.InputStream; import java.io.RandomAccessFile; import java.net.HttpURLConnection; import java.net.URL; import java.nio.ByteBuffer; import java.nio.channels.FileChannel; import android.util.Log; public class DownloadThread extends Thread { private static final String TAG = "DownloadThread"; /** 本地保存文件 */ private File saveFile; /** 下载路径 */ private URL downUrl; /** 该线程要下载的长度 */ private int block; /** 线程ID */ private int threadId = -1; /** 该线程已下载的长度 */ private int downLength; /** 是不是下载完成 */ private boolean finish = false; /** 文件下载器 */ private FileDownloader downloader; /*** * 构造方法 */ public DownloadThread(FileDownloader downloader, URL downUrl, File saveFile, int block, int downLength, int threadId) { this.downUrl = downUrl; this.saveFile = saveFile; this.block = block; this.downloader = downloader; this.threadId = threadId; this.downLength = downLength; } /** * 线程主方法 */ @Override public void run() { if (downLength < block) {// 未下载完成 try { HttpURLConnection http = (HttpURLConnection) downUrl .openConnection(); http.setConnectTimeout(5 * 1000); http.setRequestMethod("GET"); http.setRequestProperty( "Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, application/x-shockwave-flash," + " application/xaml+xml, application/vnd.ms-xpsdocument, application/x-ms-xbap, " + "application/x-ms-application, application/vnd.ms-excel," + " application/vnd.ms-powerpoint, application/msword, */*"); http.setRequestProperty("Accept-Language", "zh-CN"); http.setRequestProperty("Referer", downUrl.toString()); http.setRequestProperty("Charset", "UTF⑻"); // 该线程开始下载位置 int startPos = block * (threadId - 1) + downLength; // 该线程下载结束位置 int endPos = block * threadId - 1; // 设置获得实体数据的范围 http.setRequestProperty("Range", "bytes=" + startPos + "-" + endPos); http.setRequestProperty( "User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2; Trident/4.0;" + " .NET CLR 1.1.4322; .NET CLR 2.0.50727; " + ".NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729)"); http.setRequestProperty("Connection", "Keep-Alive"); /****/ System.out.println("DownloadThread http.getResponseCode():" + http.getResponseCode()); if (http.getResponseCode() == 206) { /*** * //获得输入流 InputStream inStream = http.getInputStream(); * byte[] buffer = new byte[1024]; int offset = 0; * print("Thread " + this.threadId + * " start download from position " + startPos); * * // rwd: 打开以便读取和写入,对 "rw",还要求对文件内容的每一个更新都同步写入到基础存储装备。 * //对Android移动装备1定要注意同步,否则当移动装备断电的话会丢失数据 RandomAccessFile * threadfile = new RandomAccessFile( this.saveFile, "rwd"); * //直接移动到文件开始位置下载的 threadfile.seek(startPos); while * (!downloader.getExit() && (offset = inStream.read(buffer, * 0, 1024)) != ⑴) { threadfile.write(buffer, 0, * offset);//开始写入数据到文件 downLength += offset; //该线程和下载的长度增加 * downloader.update(this.threadId, * downLength);//修改数据库中该线程已下载的数据长度 * downloader.append(offset);//文件下载器已下载的总长度增加 } * threadfile.close(); * * print("Thread " + this.threadId + " download finish"); * this.finish = true; **/ // 获得输入流 InputStream inStream = http.getInputStream(); BufferedInputStream bis = new BufferedInputStream(inStream); byte[] buffer = new byte[1024 * 4]; int offset = 0; RandomAccessFile threadfile = new RandomAccessFile( this.saveFile, "rwd"); // 获得RandomAccessFile的FileChannel FileChannel outFileChannel = threadfile.getChannel(); // 直接移动到文件开始位置下载的 outFileChannel.position(startPos); // 分配缓冲区的大小 while (!downloader.getExit() && (offset = bis.read(buffer)) != -1) { outFileChannel .write(ByteBuffer.wrap(buffer, 0, offset));// 开始写入数据到文件 downLength += offset; // 该线程和下载的长度增加 downloader.update(this.threadId, downLength);// 修改数据库中该线程已下载的数据长度 downloader.append(offset);// 文件下载器已下载的总长度增加 } outFileChannel.close(); threadfile.close(); inStream.close(); print("Thread " + this.threadId + " download finish"); this.finish = true; } } catch (Exception e) { this.downLength = -1; print("Thread " + this.threadId + ":" + e); } } } private static void print(String msg) { Log.i(TAG, msg); } /** * 下载是不是完成 * * @return */ public boolean isFinish() { return finish; } /** * 已下载的内容大小 * * @return 如果返回值为⑴,代表下载失败 */ public long getDownLength() { return downLength; } }

FileDownloader.java

package com.amlapp.update.otaupgrade.download; import java.io.BufferedReader; import java.io.File; import java.io.InputStreamReader; import java.io.RandomAccessFile; import java.net.HttpURLConnection; import java.net.URL; import java.util.LinkedHashMap; import java.util.Map; import java.util.UUID; import java.util.concurrent.ConcurrentHashMap; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpGet; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.params.HttpConnectionParams; import org.apache.http.params.HttpParams; import android.content.Context; import android.util.Log; /** * 文件下载器 */ public class FileDownloader { private static final String TAG = "FileDownloader"; /** 上下文 */ private Context context; /** 文件下载服务类 */ private FileService fileService; /** 是不是停止下载 */ private boolean exit; /** 已下载文件长度 */ private int downloadSize = 0; /** 原始文件长度 */ private int fileSize = 0; /** 用于下载的线程数组 */ private DownloadThread[] threads; /** 本地保存文件 */ private File saveFile; /** 缓存各线程下载的长度 */ private Map<Integer, Integer> data = new ConcurrentHashMap<Integer, Integer>(); /** 每条线程下载的长度 */ private int block; /** 下载路径 */ private String downloadUrl; /** * 构建文件下载器 * * @param downloadUrl * 下载路径 * @param fileSaveDir * 文件保存目录 * @param threadNum * 下载线程数 */ public FileDownloader(Context context, String downloadUrl, File fileSaveDir, int threadNum) { try { this.context = context; this.downloadUrl = downloadUrl; fileService = new FileService(this.context); // 根据指定的下载路径,生成URL URL url = new URL(this.downloadUrl); if (!fileSaveDir.exists()) fileSaveDir.mkdirs();// 如果保存路径不存在,则新建1个目录 // 根据指定的线程数来新建线程数组 this.threads = new DownloadThread[threadNum]; // 打开HttpURLConnection HttpURLConnection conn = (HttpURLConnection) url.openConnection(); // 设置 HttpURLConnection的断开时间 conn.setConnectTimeout(5 * 1000); // 设置 HttpURLConnection的要求方式 conn.setRequestMethod("GET"); // 设置 HttpURLConnection的接收的文件类型 conn.setRequestProperty( "Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg, " + "application/x-shockwave-flash, application/xaml+xml, " + "application/vnd.ms-xpsdocument, application/x-ms-xbap, application/x-ms-application, " + "application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, */*"); // 设置 HttpURLConnection的接收语音 conn.setRequestProperty("Accept-Language", "zh-CN"); // 指定要求uri的源资源地址 conn.setRequestProperty("Referer", downloadUrl); // 设置 HttpURLConnection的字符编码 conn.setRequestProperty("Charset", "UTF⑻"); // 检查阅读页面的访问者在用甚么操作系统(包括版本号)阅读器(包括版本号)和用户个人偏好 conn.setRequestProperty( "User-Agent", "Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.2;" + " Trident/4.0; .NET CLR 1.1.4322; .NET CLR 2.0.50727; " + ".NET CLR 3.0.04506.30; .NET CLR 3.0.4506.2152;" + " .NET CLR 3.5.30729)"); conn.setRequestProperty("Connection", "Keep-Alive"); conn.connect(); // 打印Http协议头 printResponseHeader(conn); // 如果返回的状态码为200表示正常 //System.out.println("conn.getResponseCode():"+conn.getResponseCode()); if (conn.getResponseCode() == 200) { this.fileSize = conn.getContentLength();// 根据响应获得文件大小 if (this.fileSize <= 0) throw new RuntimeException("Unkown file size "); String filename = getFileName(conn);// 获得文件名称 this.saveFile = new File(fileSaveDir, filename);// 构建保存文件 Map<Integer, Integer> logdata = fileService .getData(downloadUrl);// 获得下载记录 if (logdata.size() > 0) {// 如果存在下载记录 for (Map.Entry<Integer, Integer> entry : logdata.entrySet()) data.put(entry.getKey(), entry.getValue());// 把各条线程已下载的数据长度放入data中 } if (this.data.size() == this.threads.length) {// 下面计算所有线程已下载的数据总长度 for (int i = 0; i < this.threads.length; i++) { this.downloadSize += this.data.get(i + 1); } print("已下载的长度" + this.downloadSize); } // 计算每条线程下载的数据长度 this.block = (this.fileSize % this.threads.length) == 0 ? this.fileSize / this.threads.length : this.fileSize / this.threads.length + 1; } else { throw new RuntimeException("server no response "); } } catch (Exception e) { print(e.toString()); throw new RuntimeException("don't connection this url"); } } /** * 获得线程数 */ public int getThreadSize() { return threads.length; } /** * 退出下载 */ public void exit() { this.exit = true; } /** * 是不是退出下载 */ public boolean getExit() { return this.exit; } /** * 获得文件大小 */ public int getFileSize() { return fileSize; } /** * 累计已下载大小 * 该方法在具体某个线程下载的时候会被调用 */ protected synchronized void append(int size) { downloadSize += size; } /** * 更新指定线程最后下载的位置 * 该方法在具体某个线程下载的时候会被调用 * @param threadId * 线程id * @param pos * 最后下载的位置 */ protected synchronized void update(int threadId, int pos) { // 缓存各线程下载的长度 this.data.put(threadId, pos); // 更新数据库中的各线程下载的长度 this.fileService.update(this.downloadUrl, threadId, pos); } /** * 获得文件名 * * @param conn * Http连接 */ private String getFileName(HttpURLConnection conn) { String filename = this.downloadUrl.substring(this.downloadUrl .lastIndexOf('/') + 1);// 截取下载路径中的文件名 // 如果获得不到文件名称 if (filename == null || "".equals(filename.trim())) { // 通过截取Http协议头分析下载的文件名 for (int i = 0;; i++) { String mine = conn.getHeaderField(i); if (mine == null) break; /** * Content-disposition 是 MIME 协议的扩大,MIME 协议唆使 MIME * 用户代理如何显示附加的文件。 * Content-Disposition就是当用户想把要求所得的内容存为1个文件的时候提供1个默许的文件名 * 协议头中的Content-Disposition格式以下: * Content-Disposition","attachment;filename=FileName.txt"); */ if ("content-disposition".equals(conn.getHeaderFieldKey(i) .toLowerCase())) { // 通过正则表达式匹配出文件名 Matcher m = Pattern.compile(".*filename=(.*)").matcher( mine.toLowerCase()); // 如果匹配到了文件名 if (m.find()) return m.group(1);// 返回匹配到的文件名 } } // 如果还是匹配不到文件名,则默许取1个随机数文件名 filename = UUID.randomUUID() + ".tmp"; } return filename; } /** * 开始下载文件 * * @param listener * 监听下载数量的变化,如果不需要了解实时下载的数量,可以设置为null * @return 已下载文件大小 * @throws Exception */ public int download(DownloadProgressListener listener) throws Exception { try { RandomAccessFile randOut = new RandomAccessFile(this.saveFile, "rw"); if (this.fileSize > 0) randOut.setLength(this.fileSize); randOut.close(); URL url = new URL(this.downloadUrl); // 如果本来未曾下载或本来的下载线程数与现在的线程数不1致 if (this.data.size() != this.threads.length) { this.data.clear();// 清除原来的线程数组 for (int i = 0; i < this.threads.length; i++) { this.data.put(i + 1, 0);// 初始化每条线程已下载的数据长度为0 } this.downloadSize = 0; } //循环遍历线程数组 for (int i = 0; i < this.threads.length; i++) { int downLength = this.data.get(i + 1); // 获得当前线程下载的文件长度 // 判断线程是不是已完成下载,否则继续下载 if (downLength < this.block && this.downloadSize < this.fileSize) { //启动线程开始下载 this.threads[i] = new DownloadThread(this, url, this.saveFile, this.block, this.data.get(i + 1), i + 1); this.threads[i].setPriority(7); this.threads[i].start(); } else { this.threads[i] = null; } } //如果存在下载记录,从数据库中删除它们 fileService.delete(this.downloadUrl); //重新保存下载的进度到数据库 fileService.save(this.downloadUrl, this.data); boolean notFinish = true;// 下载未完成 while (notFinish) {// 循环判断所有线程是不是完成下载 Thread.sleep(900); notFinish = false;// 假定全部线程下载完成 for (int i = 0; i < this.threads.length; i++) { if (this.threads[i] != null && !this.threads[i].isFinish()) {// 如果发现线程未完成下载 notFinish = true;// 设置标志为下载没有完成 // 如果下载失败,再重新下载 if (this.threads[i].getDownLength() == -1) { this.threads[i] = new DownloadThread(this, url, this.saveFile, this.block, this.data.get(i + 1), i + 1); this.threads[i].setPriority(7); this.threads[i].start(); } } } if (listener != null) listener.onDownloadSize(this.downloadSize,this.fileSize);// 通知目前已下载完成的数据长度 } // 如果下载完成 if (downloadSize == this.fileSize) fileService.delete(this.downloadUrl);// 下载完成删除记录 } catch (Exception e) { print(e.toString()); throw new Exception("file download error"); } return this.downloadSize; } /** * 获得Http响应头字段 * @param http * @return */ public static Map<String, String> getHttpResponseHeader( HttpURLConnection http) { Map<String, String> header = new LinkedHashMap<String, String>(); for (int i = 0;; i++) { String mine = http.getHeaderField(i); if (mine == null) break; header.put(http.getHeaderFieldKey(i), mine); } return header; } /** * 打印Http头字段 * * @param http */ public static void printResponseHeader(HttpURLConnection http) { Map<String, String> header = getHttpResponseHeader(http); for (Map.Entry<String, String> entry : header.entrySet()) { String key = entry.getKey() != null ? entry.getKey() + ":" : ""; print(key + entry.getValue()); } } /** * 获得网址内容 * @param url * @return * @throws Exception */ public static String getContent(String url) throws Exception{ StringBuilder sb = new StringBuilder(); HttpClient client = new DefaultHttpClient(); HttpParams httpParams = client.getParams(); //设置网络超时参数 HttpConnectionParams.setConnectionTimeout(httpParams, 3000); HttpConnectionParams.setSoTimeout(httpParams, 5000); HttpResponse response = client.execute(new HttpGet(url)); HttpEntity entity = response.getEntity(); if (entity != null) { BufferedReader reader = new BufferedReader(new InputStreamReader(entity.getContent(), "UTF⑻"), 8192); String line = null; while ((line = reader.readLine())!= null){ sb.append(line + "\n"); } reader.close(); } return sb.toString(); } /** * 打印信息 * @param msg 信息 */ private static void print(String msg) { Log.i(TAG, msg); } /** * 下载进度监听接口 */ public interface DownloadProgressListener { /** *下载的进度 */ public void onDownloadSize(int size,int fileSize); } }

FileService.java

package com.amlapp.update.otaupgrade.download; import java.util.HashMap; import java.util.Map; import android.content.Context; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; /** * 文件下载服务类 */ public class FileService { private DBOpenHelper openHelper; public FileService(Context context) { openHelper = new DBOpenHelper(context); } /** * 获得每条线程已下载的文件长度 * * @param path * @return */ public Map<Integer, Integer> getData(String path) { SQLiteDatabase db = openHelper.getReadableDatabase(); Cursor cursor = db .rawQuery( "select threadid, downlength from filedownlog where downpath=?", new String[] { path }); Map<Integer, Integer> data = new HashMap<Integer, Integer>(); while (cursor.moveToNext()) { data.put(cursor.getInt(0), cursor.getInt(1)); } cursor.close(); db.close(); return data; } /** * 保存每条线程已下载的文件长度 * * @param path * @param map */ public void save(String path, Map<Integer, Integer> map) {// int threadid, // int position SQLiteDatabase db = openHelper.getWritableDatabase(); db.beginTransaction(); try { for (Map.Entry<Integer, Integer> entry : map.entrySet()) { db.execSQL( "insert into filedownlog(downpath, threadid, downlength) values(?,?,?)", new Object[] { path, entry.getKey(), entry.getValue() }); } db.setTransactionSuccessful(); } finally { db.endTransaction(); } db.close(); } /** * 实时更新每条线程已下载的文件长度 * * @param path * @param map */ public void update(String path, int threadId, int pos) { SQLiteDatabase db = openHelper.getWritableDatabase(); db.execSQL( "update filedownlog set downlength=? where downpath=? and threadid=?", new Object[] { pos, path, threadId }); db.close(); } /** * 当文件下载完成后,删除对应的下载记录 * * @param path */ public void delete(String path) { SQLiteDatabase db = openHelper.getWritableDatabase(); db.execSQL("delete from filedownlog where downpath=?", new Object[] { path }); db.close(); } }

测试Activity:

package com.moonlight.projectorforge; import java.io.File; import com.amlapp.update.otaupgrade.download.FileDownloader; import com.amlapp.update.otaupgrade.download.FileDownloader.DownloadProgressListener; import android.app.Activity; import android.os.AsyncTask; import android.os.Bundle; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); new AsyncTask<String, Integer, Integer>() { private String downloadUrl = "http://image.baidu.com/search/detail?ct=503316480&z=0&ipn=d&word=asda&step_word=&pn=1&spn=0&di=145126455210&pi=&rn=1&tn=baiduimagedetail&is=&istype=0&ie=utf⑻&oe=utf⑻&in=&cl=2&lm=⑴&st=undefined&cs=3541143192%2C3632970612&os=3611388031%2C2854364844&simid=3432062895%2C349837288&adpicid=0&ln=1976&fr=&fmq=1467017028245_R&fm=&ic=undefined&s=undefined&se=&sme=&tab=0&width=&height=&face=undefined&ist=&jit=&cg=&bdtype=0&oriquery=&objurl=http%3A%2F%2Fwww.hereinuk.com%2Fwp-content%2Fuploads%2F2014%2F07%2Fasda.jpg&fromurl=ippr_z2C%24qAzdH3FAzdH3F4r_z%26e3Bojtxtg_z%26e3Bqq_z%26e3Bv54AzdH3Ff%3F__ktz%3DMzA9OTQaMTUzOA%3D%3D%264t1%3Ddaan8b99m%26t1x%3Dd%26fg%3Dkwknnw0ud19bv989jbm0c8m8dcknkdn0&gsm=0&rpstart=0&rpnum=0"; private File fileSaveDir = new File("/storage/external_storage/sda1/"); private int threadNum = 5; private int totalSize; @Override protected Integer doInBackground(String... params) { FileDownloader loader = new FileDownloader(MainActivity.this, downloadUrl, fileSaveDir, threadNum); try { loader.download(new DownloadProgressListener() { @Override public void onDownloadSize(int size, int fileSize) { totalSize = fileSize; publishProgress(size); } }); } catch (Exception e) { e.printStackTrace(); return -1; } return 0; } @Override protected void onProgressUpdate(Integer... values) { super.onProgressUpdate(values); //Todo show download progress,percentage:100f*values[0]/totalSize } @Override protected void onPostExecute(Integer result) { super.onPostExecute(result); if(result ==0){ //Todo download success }else{ //Todo download failed } } }.execute(); } }
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