Android多线程.断点续传下载

jopen 6年前

/**   * @brief  主界面       * @author lixp   */  public class HomeActivity extends Activity {      private EditText downloadpathText;      private TextView resultView;      private ProgressBar progressBar;            /**       * 当Handler被创建会关联到创建它的当前线程的消息队列,该类用于往消息队列发送消息       * 消息队列中的消息由当前线程内部进行处理       * 使用Handler更新UI界面信息。       */      private Handler handler = new Handler(){      @Override  public void handleMessage(Message msg) {  switch (msg.what) {  case 1:  progressBar.setProgress(msg.getData().getInt("size"));  float num = (float)progressBar.getProgress()/(float)progressBar.getMax();  int result = (int)(num*100);  resultView.setText(result+ "%");    //显示下载成功信息  if(progressBar.getProgress()==progressBar.getMax()){  Toast.makeText(HomeActivity.this, R.string.success, 1).show();  }  break;  case -1:  //显示下载错误信息  Toast.makeText(HomeActivity.this, R.string.error, 1).show();  break;   }   }  };            @Override      public void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.main);                    downloadpathText = (EditText) this.findViewById(R.id.path);          progressBar = (ProgressBar) this.findViewById(R.id.downloadbar);          resultView = (TextView) this.findViewById(R.id.resultView);                    Button button = (Button) this.findViewById(R.id.button);          button.setOnClickListener(new View.OnClickListener() {  @Override  public void onClick(View v) {  String path = downloadpathText.getText().toString();  System.out.println(Environment.getExternalStorageState()+"------"+Environment.MEDIA_MOUNTED);    if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){  //开始下载文件  download(path, Environment.getExternalStorageDirectory());  }else{  //显示SDCard错误信息  Toast.makeText(HomeActivity.this, R.string.sdcarderror, 1).show();  }  }  });  }          /**    * 主线程(UI线程)    * 对于显示控件的界面更新只是由UI线程负责,如果是在非UI线程更新控件的属性值,更新后的显示界面不会反映到屏幕上    * 如果想让更新后的显示界面反映到屏幕上,需要用Handler设置。    * @param path   lixp    * @param savedir    */      private void download(final String path, final File savedir) {      new Thread(new Runnable() {  @Override  public void run() {  //开启3个线程进行下载  FileDownloader loader = new FileDownloader(HomeActivity.this, path, savedir, 3);      progressBar.setMax(loader.getFileSize());//设置进度条的最大刻度为文件的长度       try {  loader.download(new DownloadProgressListener() {  @Override  public void onDownloadSize(int size) {//实时获知文件已经下载的数据长度  Message msg = new Message();  msg.what = 1;  msg.getData().putInt("size", size);  handler.sendMessage(msg);//发送消息  }  });  } catch (Exception e) {  handler.obtainMessage(-1).sendToTarget();  }  }  }).start();  }    }    二.    /**   * 下载线程类   * @author lixp   */  public class DownloadThread extends Thread {  private static final String TAG = "DownloadThread";  private File saveFile;  private URL downUrl;  private int block;    /* 下载开始位置  */  private int threadId = -1;  private int downLength;  private boolean finish = false;  private FileDownloader downloader;    /**  * @param downloader:下载器  * @param downUrl:下载地址  * @param saveFile:下载路径  *   */  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;  }    @Override  public void run() {  if(downLength < block){//未下载完成  try {  //使用Get方式下载  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", "UTF-8");    int startPos = block * (threadId - 1) + downLength;//开始位置  int endPos = block * threadId -1;//结束位置  http.setRequestProperty("Range", "bytes=" + startPos + "-"+ endPos);//设置获取实体数据的范围  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");    InputStream inStream = http.getInputStream();  byte[] buffer = new byte[1024];  int offset = 0;  print("Thread " + this.threadId + " start download from position "+ startPos);  RandomAccessFile threadfile = new RandomAccessFile(this.saveFile, "rwd");  threadfile.seek(startPos);    while ((offset = inStream.read(buffer, 0, 1024)) != -1) {  threadfile.write(buffer, 0, offset);  downLength += offset;  downloader.update(this.threadId, downLength);  downloader.append(offset);  }    threadfile.close();  inStream.close();  print("Thread " + this.threadId + " download finish");  this.finish = true;  } catch (Exception e) {  this.downLength = -1;  print("Thread "+ this.threadId+ ":"+ e);  }  }  }  /**  * 下载是否完成  */  public boolean isFinish() {  return finish;  }    /**  * 已经下载的内容大小  * @return 如果返回值为-1,代表下载失败  */  public long getDownLength() {  return downLength;  }  }    三.//lixp  public class FileDownloader {  private static final String TAG = "FileDownloader";  private Context context;  private FileService fileService;    /* 已下载文件长度 */  private int downloadSize = 0;    /* 原始文件长度 */  private int fileSize = 0;    /* 线程数 */  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;  /**  * 获取线程数  */  public int getThreadSize() {  return threads.length;  }  /**  * 获取文件大小  * @return  */  public int getFileSize() {  return fileSize;  }    /**  * 累计已下载大小  * @param size  */  protected synchronized void append(int size) {  downloadSize += size;  }    /**  * 更新指定线程最后下载的位置  * @param threadId 线程id  * @param pos 最后下载的位置  */  protected synchronized void update(int threadId, int pos) {  this.data.put(threadId, pos);  this.fileService.update(this.downloadUrl, this.data);  }    /**  * 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);  URL url = new URL(this.downloadUrl);  if(!fileSaveDir.exists()) fileSaveDir.mkdirs();  this.threads = new DownloadThread[threadNum];    HttpURLConnection conn = (HttpURLConnection) url.openConnection();  conn.setConnectTimeout(5*1000);  conn.setRequestMethod("GET");  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,*/*");  conn.setRequestProperty("Accept-Language", "zh-CN");  conn.setRequestProperty("Referer", downloadUrl);   conn.setRequestProperty("Charset", "UTF-8");  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();  printResponseHeader(conn);    if (conn.getResponseCode()==200) {  this.fileSize = conn.getContentLength();//根据响应获取文件大小  if (this.fileSize <= 0) throw new RuntimeException("Unkown file size ");    String filename = getFileName(conn);//获取文件名称  this.saveFile = new File(fileSaveDir, filename);//构建保存文件  Map<Integer, Integer> logdata = fileService.getData(downloadUrl);//获取下载记录    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());//把各条线程已经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经下载的数据长度  for (int i = 0; i < this.threads.length; i++) {  this.downloadSize += this.data.get(i+1);  }    print("已经下载的长度"+ 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");  }  }    /**  * 获取文件名  * @param conn  * @return  */  private String getFileName(HttpURLConnection conn) {  String filename = this.downloadUrl.substring(this.downloadUrl.lastIndexOf('/') + 1);    if(filename==null || "".equals(filename.trim())){//如果获取不到文件名称  for (int i = 0;; i++) {  String mine = conn.getHeaderField(i);    if (mine == null) break;    if("content-disposition".equals(conn.getHeaderFieldKey(i).toLowerCase())){  Matcher m = Pattern.compile(".*filename=(.*)").matcher(mine.toLowerCase());  if(m.find()) return m.group(1);  }  }    filename = UUID.randomUUID()+ ".tmp";//默认取一个文件名  }    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);    if(this.data.size() != this.threads.length){  this.data.clear();    for (int i = 0; i < this.threads.length; i++) {  this.data.put(i+1, 0);//初始化每条线程已经下载的数据长度为0  }  }    for (int i = 0; i < this.threads.length; i++) {//开启线程进行下载  int downLength = this.data.get(i+1);    if(downLength < this.block && this.downloadSize<this.fileSize){//判断线程是否已经完成下载,否则继续下载  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;  }  }    this.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否完成下载  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    if(this.threads[i].getDownLength() == -1){//如果下载失败,再重新下载  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();  }  }  }    if(listener!=null) listener.onDownloadSize(this.downloadSize);//通知目前已经下载完成的数据长度  }    fileService.delete(this.downloadUrl);  } catch (Exception e) {  print(e.toString());  throw new Exception("file download fail");  }  return this.downloadSize;  }    /**  * 获取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());  }  }    /**  * 打印日志信息  * @param msg  */  private static void print(String msg){  Log.i(TAG, msg);  }  }    四.**   * 数据库操作类   * @author lixp   */  public class DBOpenHelper extends SQLiteOpenHelper {  private static final String DBNAME = "down.db";  private static final int VERSION = 1;    /**  * 构造器  * @param context  */  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);  }  }    五.//下载工具类  public class FileService {  private DBOpenHelper openHelper;  public FileService(Context context) {  openHelper = new DBOpenHelper(context);  }  /**  * 获取每条线程已经下载的文件长度  * @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;  }    /**  * 保存每条线程已经下载的文件长度  * @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经下载的文件长度  * @param path  * @param map  */  public void update(String path, Map<Integer, Integer> map){  SQLiteDatabase db = openHelper.getWritableDatabase();  db.beginTransaction();    try{  for(Map.Entry<Integer, Integer> entry : map.entrySet()){  db.execSQL("update filedownlog set downlength=? where downpath=? and threadid=?",  new Object[]{entry.getValue(), path, entry.getKey()});  }  db.setTransactionSuccessful();  }finally{  db.endTransaction();  }  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();  }  }