断点下载数据
public class MainActivity extends Activity { private EditText pathText; private TextView resultView; private Button downloadButton; private Button stopbutton; private ProgressBar progressBar; //hanlder的作用是用于往创建Hander对象所在的线程所绑定的消息队列发送消息 private Handler handler = new UIHander(); private final class UIHander extends Handler{//重写Handler中的handleMessage方法 public void handleMessage(Message msg) { switch (msg.what) {//msg.what Message的标记 case 1: int size = msg.getData().getInt("size");//从消息的数据中取出其他线程存进的数据 progressBar.setProgress(size); float num = (float)progressBar.getProgress() / (float)progressBar.getMax(); int result = (int)(num * 100); resultView.setText(result+ "%"); if(progressBar.getProgress() == progressBar.getMax()){ Toast.makeText(getApplicationContext(), R.string.success, 1).show(); } break; case -1: Toast.makeText(getApplicationContext(), R.string.error, 1).show(); break; } } } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); pathText = (EditText) this.findViewById(R.id.path); resultView = (TextView) this.findViewById(R.id.resultView); downloadButton = (Button) this.findViewById(R.id.downloadbutton); stopbutton = (Button) this.findViewById(R.id.stopbutton); progressBar = (ProgressBar) this.findViewById(R.id.progressBar); ButtonClickListener listener = new ButtonClickListener(); downloadButton.setOnClickListener(listener); stopbutton.setOnClickListener(listener); } private final class ButtonClickListener implements View.OnClickListener{ public void onClick(View v) { switch (v.getId()) { case R.id.downloadbutton: String path = pathText.getText().toString(); if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){ File saveDir = Environment.getExternalStorageDirectory(); download(path, saveDir); }else{ Toast.makeText(getApplicationContext(), R.string.sdcarderror, 1).show(); } downloadButton.setEnabled(false); stopbutton.setEnabled(true); break; case R.id.stopbutton: exit(); downloadButton.setEnabled(true); stopbutton.setEnabled(false); break; } } /* 由于用户的输入事件(点击button, 触摸屏幕....)是由主线程负责处理的，如果主线程处于工作状态， 此时用户产生的输入事件如果没能在5秒内得到处理，系统就会报“应用无响应”错误。 所以在主线程里不能执行一件比较耗时的工作，否则会因主线程阻塞而无法处理用户的输入事件， 导致“应用无响应”错误的出现。耗时的工作应该在子线程里执行。 */ private DownloadTask task; /** * 退出下载 */ public void exit(){ if(task!=null) task.exit(); } private void download(String path, File saveDir) {//运行在主线程 task = new DownloadTask(path, saveDir); new Thread(task).start(); } /* * UI控件画面的重绘(更新)是由主线程负责处理的，如果在子线程中更新UI控件的值，更新后的值不会重绘到屏幕上 * 一定要在主线程里更新UI控件的值，这样才能在屏幕上显示出来，不能在子线程中更新UI控件的值 */ private final class DownloadTask implements Runnable{ private String path; private File saveDir; private FileDownloader loader; public DownloadTask(String path, File saveDir) { this.path = path; this.saveDir = saveDir; } /** * 退出下载 */ public void exit(){ if(loader!=null) loader.exit(); } public void run() { try { loader = new FileDownloader(getApplicationContext(), path, saveDir, 3); progressBar.setMax(loader.getFileSize());//设置进度条的最大刻度 loader.download(new DownloadProgressListener() { public void onDownloadSize(int size) { Message msg = new Message(); msg.what = 1; msg.getData().putInt("size", size); handler.sendMessage(msg);//向创建handler对象的线程发送消息 } }); } catch (Exception e) { e.printStackTrace(); handler.sendMessage(handler.obtainMessage(-1)); } } } } }
/** * 文件下载器 * try { FileDownloader loader = new FileDownloader(context, "http://browse.babasport.com/ejb3/ActivePort.exe", new File("D:\\androidsoft\\test"), 2); loader.getFileSize();//得到文件总大小 loader.download(new DownloadProgressListener(){ public void onDownloadSize(int size) { print("已经下载："+ size); } }); } catch (Exception e) { e.printStackTrace(); } */ public class FileDownloader { private static final String TAG = "FileDownloader"; private Context context; //上下文对象 private FileService fileService; /* 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; /* 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; } /** * 退出下载 */ public void exit(){ this.exit = true; } public boolean getExit(){ return this.exit; } /** * 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, threadId, pos); } /** * 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; //下载地址 fileService = new FileService(this.context); URL url = new URL(this.downloadUrl); if(!fileSaveDir.exists()) fileSaveDir.mkdirs();//判断下载文件保存目录是否存在，不存在创建 this.threads = new DownloadThread[threadNum]; //创建一个线程数组 HttpURLConnection conn = (HttpURLConnection) url.openConnection(); //设置头字段 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);//获取每条线程已经下载的文件长度 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总长度 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 */ 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){//如果原先未曾下载或者原先的下载线程数与现在的线程数不一致 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 } this.downloadSize = 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; } } fileService.delete(this.downloadUrl);//如果存在下载记录，删除它们，然后重新添加 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 } 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()); } } private static void print(String msg){ Log.i(TAG, msg); } }
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; 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 { 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 (!downloader.getExit() && (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); } } } private static void print(String msg){ Log.i(TAG, msg); } /** * 下载是否完成 * @return */ 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; } }
public interface DownloadProgressListener { public void onDownloadSize(int size); }
/** * 业务bean * */ 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, 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(); } }
public class DBOpenHelper extends SQLiteOpenHelper { private static final String DBNAME = "itcast.db"; 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); } }
<ProgressBar
android:layout_width="fill_parent"
android:layout_height="18dp"
style="?android:attr/progressBarStyleHorizontal" //使用系统中的横向滚动条
android:id="@+id/progressBar"
/>
