<resources>
    <string >Hello World, MainActivity!</string>
    <string >Android网络多线程断点下载</string>
    <string >下载路径</string>
    <string >下载</string>
    <string >SDCard不存在或者写保护</string>
    <string >下载完成</string>
    <string >下载失败</string>
</resources>

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<!-- 下载路径 -->
    <android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/path"/>
    <android:id="@+id/path"        android:text="http://www.winrar.com.cn/download/wrar380sc.exe"        android:layout_width="fill_parent"        android:layout_height="wrap_content">
    </EditText>
    <!-- 下载按钮 -->
    <android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/downloadbutton"
        android:id="@+id/button"/>
    <!-- 进度条 -->
    <android:layout_width="fill_parent"
        android:layout_height="20dip"
        style="?android:attr/progressBarStyleHorizontal"
        android:id="@+id/downloadbar"/>
    <android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:id="@+id/resultView"/>
    </LinearLayout>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"      package="com.android.downloader"      android:versionCode="1"      android:versionName="1.0">
<uses-sdk android:minSdkVersion="8"/>

<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".MainActivity"
                  android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>

</application>

<!-- 在SDCard中创建与删除文件权限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>

<!-- 往SDCard写入数据权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

<!-- 访问internet权限 -->
<uses-permission android:name="android.permission.INTERNET"/>

import java.io.File;

import com.android.network.DownloadProgressListener;
import com.android.network.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;

publicclass MainActivity 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
        publicvoid 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(MainActivity.this, R.string.success, 1).show();
                }
                break;
            case -1:
                Toast.makeText(MainActivity.this, R.string.error, 1).show();
                break;
            }
        }
    };
    
    /** Called when the activity is first created. */
    @Override
    publicvoid 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
            publicvoid onClick(View v) {
                // TODO Auto-generated method stub
                String path = downloadpathText.getText().toString();
                System.out.println(Environment.getExternalStorageState()+"------"+Environment.MEDIA_MOUNTED);
                
                if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
                    download(path, Environment.getExternalStorageDirectory());
                }else{
                    Toast.makeText(MainActivity.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
       * @param@param*/
    privatevoid download(final String path, final File savedir) {
        new Thread(new Runnable() {            
            @Override
            publicvoid run() {
                FileDownloader loader = new FileDownloader(MainActivity.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
                        publicvoid 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();
    }

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

publicclass DBOpenHelper extends SQLiteOpenHelper {
    privatestaticfinal String DBNAME = "down.db";
    privatestaticfinalint VERSION = 1;
    
    public DBOpenHelper(Context context) {
        super(context, DBNAME, null, VERSION);
    }
    
    @Override
    publicvoid onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE IF NOT EXISTS filedownlog (id integer primary key autoincrement, downpath varchar(100), threadid INTEGER, downlength INTEGER)");
    }

@Override
    publicvoid onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS filedownlog");
        onCreate(db);
    }
}

import java.util.HashMap;
import java.util.Map;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

publicclass 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@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@param*/
    publicvoid 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@param*/
    publicvoid 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*/
    publicvoid delete(String path){
        SQLiteDatabase db = openHelper.getWritableDatabase();
        db.execSQL("delete from filedownlog where downpath=?", new Object[]{path});
        db.close();
    }

publicinterface DownloadProgressListener {
    publicvoid onDownloadSize(int size);

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 com.android.service.FileService;

import android.content.Context;
import android.util.Log;

publicclass FileDownloader {
    privatestaticfinal String TAG = "FileDownloader";
    private Context context;
    private FileService fileService;    
    
    /* 已下载文件长度 */
    privateint downloadSize = 0;
    
    /* 原始文件长度 */
    privateint 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 */
    privateint block;
    
    /* 下载路径  */
    private String downloadUrl;
    
    /***/
    publicint getThreadSize() {
        return threads.length;
    }
    
    /**@return
     */
    publicint getFileSize() {
        return fileSize;
    }
    
    /**@param*/
    protectedsynchronizedvoid append(int size) {
        downloadSize += size;
    }
    
    /**@param@param*/
    protectedsynchronizedvoid update(int threadId, int pos) {
        this.data.put(threadId, pos);
        this.fileService.update(this.downloadUrl, this.data);
    }
    
    /**@param@param@param*/
    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) thrownew 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{
                thrownew RuntimeException("server no response ");
            }
        } catch (Exception e) {
            print(e.toString());
            thrownew RuntimeException("don't connection this url");
        }
    }
    
    /**@param@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;
    }
    
    /**@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@throws*/
    publicint 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());
            thrownew Exception("file download fail");
        }
        returnthis.downloadSize;
    }
    
    /**@param@return
     */
    publicstatic 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;
    }
    
    /**@param*/
    publicstaticvoid 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());
        }
    }

privatestaticvoid print(String msg){
        Log.i(TAG, msg);
    }
}