Android通过HTTP协议实现断点续传下载

 // FileDownloader.java                                                                      package cn.itcast.net.download;      import java.io.File;   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 cn.itcast.service.FileService;      import android.content.Context;   import android.util.Log;   /**   * 文件下载器   * 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          try {              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;       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        */       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());           }       }          private static void print(String msg){           Log.i(TAG, msg);       }   }  

DownloadThread.Java

[java]  view plain  copy package cn.itcast.net.download;      import java.io.File;   import java.io.InputStream;   import java.io.RandomAccessFile;   import java.net.HttpURLConnection;   import java.net.URL;      import android.util.Log;      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 ((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;       }   }  

DownloadProgressListener.java

[java]  view plain  copy package cn.itcast.net.download;      public interface DownloadProgressListener {       public void onDownloadSize(int size);   }  

DBOpenHelper.java

[java]  view plain  copy package cn.itcast.service;      import android.content.Context;   import android.database.sqlite.SQLiteDatabase;   import android.database.sqlite.SQLiteOpenHelper;      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);       }      }  

FileService.java

[java]  view plain  copy package cn.itcast.service;      import java.util.HashMap;   import java.util.Map;      import android.content.Context;   import android.database.Cursor;   import android.database.sqlite.SQLiteDatabase;   /**   * 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, 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();       }          }  

DownloadActivity.java

[java]  view plain  copy package cn.itcast.download;      import java.io.File;      import cn.itcast.net.download.DownloadProgressListener;   import cn.itcast.net.download.FileDownloader;      import android.app.Activity;   import android.os.Bundle;   import android.os.Environment;   import android.os.Handler;   import android.os.Message;   import android.view.View;   import android.widget.Button;   import android.widget.EditText;   import android.widget.ProgressBar;   import android.widget.TextView;   import android.widget.Toast;      public class DownloadActivity 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       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+ "%");                   if(progressBar.getProgress()==progressBar.getMax()){                       Toast.makeText(DownloadActivity.this, R.string.success, 1).show();                   }                   break;                  case -1:                   Toast.makeText(DownloadActivity.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.downloadpath);           progressBar = (ProgressBar) this.findViewById(R.id.downloadbar);           resultView = (TextView) this.findViewById(R.id.result);           Button button = (Button) this.findViewById(R.id.button);           button.setOnClickListener(new View.OnClickListener() {                         @Override               public void onClick(View v) {                   String path = downloadpathText.getText().toString();                   if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){                       download(path, Environment.getExternalStorageDirectory());                   }else{                       Toast.makeText(DownloadActivity.this, R.string.sdcarderror, 1).show();                   }                                  }           });       }       //主线程(UI线程)       //业务逻辑正确，但是该程序运行的时候有问题       //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       private void download(final String path, final File savedir) {           new Thread(new Runnable() {                        @Override               public void run() {                   FileDownloader loader = new FileDownloader(DownloadActivity.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();       }   }