android手机多线程断点续传下载器案例源码

软件测试界面

功能介绍：输入下载地址后，点击下载，进度条显示下载的百分比，处于下载时下载按钮无法使用，未开始下载，停止按钮无法使用

完整代码分析：

1.界面创建：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/path" />

    <EditText
        android:id="@+id/path"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="http://192.168.0.117/testxml/xunlei.exe" />
<LinearLayout 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal" 
    >
    <!--下载按钮-->
     <Button
        android:id="@+id/downloadbutton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/button" />
     <!--停止按钮-->
      <Button
        android:id="@+id/stopbutton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/stopbutton" 
        android:enabled="false"/>
      
</LinearLayout>

    <ProgressBar
        android:id="@+id/progressBar"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="fill_parent"
        android:layout_height="18dp" />
<!--进度条下面的百分比-->
    <TextView
        android:id="@+id/resultview"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:gravity="center" />

</LinearLayout>

2.清单文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="caicai.cn.multhreaddownloader"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="8" />  
    <uses-permission android:name="android.permission.INTERNET"/>
    <!--允许装备或解除可移除的存储仓库的文件系统 -->
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
    <!--允许写入外存储设备即SDcard -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

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

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

3.界面操作

package caicai.cn.multhreaddownloader;

import java.io.File;

import net.download.DownloadProgressListener;
import 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 Cai_multhreaddownloaderActivity extends Activity {
    private EditText pathtext;
    private TextView resultview;
    private Button downloadbutton;
    private Button stopbutton;
    private ProgressBar progressBar;
    private Handler handler = new Uihandler();

    // handler用于往创建handler对象所在的线程所绑定的消息队列发送消息

    private final class Uihandler extends Handler {// 接收从子线程传来的值，注意只有主线程才能对UI控件进行控制与更新
        public void handleMessage(Message msg) {
            switch (msg.what) {
            case 1:
                int size = msg.getData().getInt("size");
                progressBar.setProgress(size);// 当前刻度;
                float num = (float) progressBar.getProgress()
                        / (float) progressBar.getMax();
                int result = (int) (num * 100);
                resultview.setText(result + "%");
                if (progressBar.getProgress() == progressBar.getMax()) {
                    Toast.makeText(getApplicationContext(), "下载完成", 1).show();
                }
                break;
            case -1:
                Toast.makeText(getApplicationContext(), R.string.error, 1)
                        .show();
                break;
            }

        }
    }

    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();// 获取下载路径
                if (Environment.getExternalStorageState().equals(
                        Environment.MEDIA_MOUNTED)) {// 判断SDcard是否存在 或者可写数据
                    File savedir = Environment.getExternalStorageDirectory();// 获取sdcard跟目录，即保存路径
                    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;
        private void exit() {//退出下载
            if (task!= null) {
                task.exit();
            }
        };

        private void download(String path, File savedir) {
            task = new DownloadTask(path, savedir);
            new Thread(task).start();
        }

        private final class DownloadTask implements Runnable {
            String path;
            File savedir;
            FileDownloader loader;

            public DownloadTask(String path, File savedir) {
                this.path = path;
                this.savedir = savedir;
            }

            public void exit() {
                if (loader != null) {
                    loader.exit();// 退出下载
                }
            }

            @Override
            public void run() {
                try {
                    loader = new FileDownloader(getApplicationContext(), path,
                            savedir, 3);
                    progressBar.setMax(loader.getFileSize());// 设置进度条最大刻度
                    loader.download(new DownloadProgressListener() {
                        @Override
                        public void onDownloadSize(int size) {
                            Message msg = new Message();
                            msg.what = 1;// 定义消息的ID，以便区别那个消息发过来的
                            msg.getData().putInt("size", size);
                            handler.sendMessage(msg);

                        }
                    });
                } catch (Exception e) {
                    e.printStackTrace();
                    handler.sendMessage(handler.obtainMessage(-1));// 发送编号为-1的空消息
                }

            }

        }
    }
}

4.下载接口

package net.download;

public interface DownloadProgressListener {
    public void onDownloadSize(int size);
}

5.下载线程类

package 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 (!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;
    }
}

6.文件下载器

package 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  service.FileService;

import android.content.Context;
import android.util.Log;
/**
 * 文件下载器使用类案例
 * 
    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;
    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;
            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);
    }
}

7.数据库操作类

package 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 = "download.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);
    }

}

8.下载的进度存入数据库操作类

package 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, 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();
    }
    
}