断点续传---多线程下载进阶（二）
流程：
/** * 断点续传：就是下载如果暂停后，下次下载时候，继续从上次下载的位置开始下载即可 * 大致流程： * 点击下载后，开始一个service,在onStartCommand中进行 * InitThread开始分线程进行获取网络资源的大小，获取完毕发送消息MSG_INIT， * 进行downLoad，下载前判断，是否下载过，如果么有就初始化 * threadInfo = new ThreadInfo(0, mFileInfo.getUrl(), 0, mFileInfo.getLength(), 0); 如果又下载就进行获取， 然后开启分线程进行下载 new DownloadThread(threadInfo).start(); 下载操作：向数据库插入线程信息，设置下载位置，设置文件写入位置，开始进行下载 下载时候，通过handler发送广播（传递下载进度值）， 在广播接收器中进行mProgressBar.setProgress(finised);设置进度即可 下载完毕，发送消息，进行Toast.makeText(mMainActivity, "下载完毕", 0).show(); * */
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<TextView
android:id="@+id/tv_fileName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="imooc.apk" />
<ProgressBar
android:id="@+id/pb_progress"
style="?android:attr/progressBarStyleHorizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/tv_fileName" />
<Button
android:id="@+id/btn_stop"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/pb_progress"
android:layout_alignParentRight="true"
android:text="暂停" />
<Button
android:id="@+id/btn_start"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/pb_progress"
android:layout_toLeftOf="@id/btn_stop"
android:text="下载" />
</RelativeLayout>
FileInfo
package com.download.entities;
import java.io.Serializable;
public class FileInfo implements Serializable {
private int id;
private String url;
private String fileName;
private int length;
private int finished;
public FileInfo(int id, String url, String fileName, int length,
int finished) {
this.id = id;
this.url = url;
this.fileName = fileName;
this.length = length;
this.finished = finished;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getFileName() {
return fileName;
}
public void setFileName(String fileName) {
this.fileName = fileName;
}
public int getLength() {
return length;
}
public void setLength(int length) {
this.length = length;
}
public int getFinished() {
return finished;
}
public void setFinished(int finished) {
this.finished = finished;
}
@Override
public String toString() {
return "FileInfo [id=" + id + ", url=" + url + ", fileName=" + fileName
+ ", length=" + length + ", finished=" + finished + "]";
}
}
ThreadInfo
package com.download.entities;
public class ThreadInfo {
/**
* 对应数据库的字段即可
*/
private int id;
private String url;
private int start;
private int end;
private int finished;
public ThreadInfo() {
}
public ThreadInfo(int id, String url, int start, int end, int finished) {
this.id = id;
this.url = url;
this.start = start;
this.end = end;
this.finished = finished;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public int getStart() {
return start;
}
public void setStart(int start) {
this.start = start;
}
public int getEnd() {
return end;
}
public void setEnd(int end) {
this.end = end;
}
public int getFinished() {
return finished;
}
public void setFinished(int finished) {
this.finished = finished;
}
@Override
public String toString() {
return "ThreadInfo [id=" + id + ", url=" + url + ", start=" + start
+ ", end=" + end + ", finished=" + finished + "]";
}
}
DBHelper
package com.download.db;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
/**
* 数据库帮助类
*/
public class DBHelper extends SQLiteOpenHelper {
private static final String DB_NAME = "download.db";
private static final int VERSION = 1;
//字段：id、thread_id、url、start、end、finished
private static final String SQL_CREATE = "create table thread_info(_id integer primary key autoincrement,"
+ "thread_id integer, url text, start integer, end integer, finished integer)";
private static final String SQL_DROP = "drop table if exists thread_info";
public DBHelper(Context context) {
super(context, DB_NAME, null, VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(SQL_CREATE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL(SQL_DROP);
db.execSQL(SQL_CREATE);
}
}
ThreadDAO
package com.download.db;
import java.util.List;
import com.download.entities.ThreadInfo;
public interface ThreadDAO {
/**
* 插入线程信息
*/
public void insertThread(ThreadInfo threadInfo);
/**
* 删除线程信息
*/
public void deleteThread(String url, int thread_id);
/**
* 更新线程下载进度
*/
public void updateThread(String url, int thread_id, int finished);
/**
* 查询文件的线程信息
*/
public List<ThreadInfo> getThreads(String url);
/**
* 线程信息是否存在
*/
public boolean isExists(String url, int thread_id);
}
ThreadDAOImpl
package com.download.db;
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import com.download.entities.ThreadInfo;
/**
* 数据访问接口实现
*/
public class ThreadDAOImpl implements ThreadDAO {
private DBHelper mHelper = null;
public ThreadDAOImpl(Context context) {
mHelper = new DBHelper(context);
}
@Override
public void insertThread(ThreadInfo threadInfo) {
SQLiteDatabase db = mHelper.getWritableDatabase();
db.execSQL(
"insert into thread_info(thread_id,url,start,end,finished) values(?,?,?,?,?)",
new Object[] { threadInfo.getId(), threadInfo.getUrl(),
threadInfo.getStart(), threadInfo.getEnd(),
threadInfo.getFinished() });
db.close();
}
@Override
public void deleteThread(String url, int thread_id) {
SQLiteDatabase db = mHelper.getWritableDatabase();
db.execSQL("delete from thread_info where url = ? and thread_id = ?",
new Object[] { url, thread_id });
db.close();
}
@Override
public void updateThread(String url, int thread_id, int finished) {
SQLiteDatabase db = mHelper.getWritableDatabase();
db.execSQL(
"update thread_info set finished = ? where url = ? and thread_id = ?",
new Object[] { finished, url, thread_id });
db.close();
}
@Override
public List<ThreadInfo> getThreads(String url) {
List<ThreadInfo> list = new ArrayList<ThreadInfo>();
SQLiteDatabase db = mHelper.getWritableDatabase();
Cursor cursor = db.rawQuery("select * from thread_info where url = ?",
new String[] { url });
while (cursor.moveToNext()) {
ThreadInfo threadInfo = new ThreadInfo();
threadInfo.setId(cursor.getInt(cursor.getColumnIndex("thread_id")));
threadInfo.setUrl(cursor.getString(cursor.getColumnIndex("url")));
threadInfo.setStart(cursor.getInt(cursor.getColumnIndex("start")));
threadInfo.setEnd(cursor.getInt(cursor.getColumnIndex("end")));
threadInfo.setFinished(cursor.getInt(cursor
.getColumnIndex("finished")));
list.add(threadInfo);
}
cursor.close();
db.close();
return list;
}
@Override
public boolean isExists(String url, int thread_id) {
SQLiteDatabase db = mHelper.getWritableDatabase();
Cursor cursor = db.rawQuery(
"select * from thread_info where url = ? and thread_id = ?",
new String[] { url, thread_id + "" });
boolean exists = cursor.moveToNext();
cursor.close();
db.close();
return exists;
}
}
MainActivity
package com.download.app;
import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Handler;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import com.download.entities.FileInfo;
import com.download.services.DownloadService;
import com.imooc.DownLoad.R;
public class MainActivity extends Activity {
// 进度条
private ProgressBar mProgressBar = null;
// 开始
private Button mStartBtn = null;
// 暂停
private Button mStopBtn = null;
public static MainActivity mMainActivity = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 初始化控件
mProgressBar = (ProgressBar) findViewById(R.id.pb_progress);
mStartBtn = (Button) findViewById(R.id.btn_start);
mStopBtn = (Button) findViewById(R.id.btn_stop);
// 将进度条设置为最大
mProgressBar.setMax(100);
/**
* 参数：(int id, String url, String fileName, int length,int finished)
*
*/
final FileInfo fileInfo = new FileInfo(0,
"http://www.imooc.com/mobile/imooc.apk", "imooc.apk", 0, 0);
// 添加事件监听
mStartBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
/**
* 通过Intent传递参数给Service
*/
Intent intent = new Intent(MainActivity.this,
DownloadService.class);
//设置intent的标记
intent.setAction(DownloadService.ACTION_START);
intent.putExtra("fileInfo", fileInfo);
startService(intent);
}
});
mStopBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// 通过Intent传递参数给Service
Intent intent = new Intent(MainActivity.this,
DownloadService.class);
intent.setAction(DownloadService.ACTION_STOP);
intent.putExtra("fileInfo", fileInfo);
startService(intent);
}
});
// 注册广播接收器
IntentFilter filter = new IntentFilter();
filter.addAction(DownloadService.ACTION_UPDATE);
registerReceiver(mReceiver, filter);
mMainActivity = this;
}
/**
* 更新UI的广播接收器
*/
BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
if (DownloadService.ACTION_UPDATE.equals(intent.getAction())) {
int finised = intent.getIntExtra("finished", 0);
mProgressBar.setProgress(finised);
}
}
};
/**
* 监听返回键
*
* @see android.app.Activity#onKeyUp(int, android.view.KeyEvent)
*/
@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
if (KeyEvent.KEYCODE_BACK == keyCode && mStartBtn != null) // 按了返回键时应暂停下载
{
mStopBtn.performClick(); // 模拟按下暂停按钮
}
return super.onKeyUp(keyCode, event);
}
public Handler handler = new Handler() {
public void handleMessage(android.os.Message msg) {
Toast.makeText(mMainActivity, "下载完毕", 0).show();
}
};
/**
* 退出后，注销广播接收器
*/
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(mReceiver);
}
}
DownloadService
package com.download.services;
import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.URL;
import org.apache.http.HttpStatus;
import com.download.entities.FileInfo;
import android.app.Service;
import android.content.Intent;
import android.os.Environment;
import android.os.Handler;
import android.os.IBinder;
import android.util.Log;
public class DownloadService extends Service {
public static final String ACTION_START = "ACTION_START";
public static final String ACTION_STOP = "ACTION_STOP";
public static final String ACTION_UPDATE = "ACTION_UPDATE";
public static final int MSG_INIT = 0;
private DownloadTask mTask = null;
private String TAG = "DownloadService";
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
// 获得Activity传过来的参数
if (ACTION_START.equals(intent.getAction())) {
//获取intent传递过来的，携带的FileInfo信息
FileInfo fileInfo = (FileInfo) intent
.getSerializableExtra("fileInfo");
// 启动初始化线程
new InitThread(fileInfo).start();
} else if (ACTION_STOP.equals(intent.getAction())) {
FileInfo fileInfo = (FileInfo) intent
.getSerializableExtra("fileInfo");
if (mTask != null) {
mTask.isPause = true;
}
}
return super.onStartCommand(intent, flags, startId);
}
private Handler mHandler = new Handler() {
public void handleMessage(android.os.Message msg) {
switch (msg.what) {
case MSG_INIT:
FileInfo fileInfo = (FileInfo) msg.obj;
Log.i(TAG, "Init:" + fileInfo);
// 启动下载任务
mTask = new DownloadTask(DownloadService.this, fileInfo);
mTask.downLoad();
break;
default:
break;
}
};
};
/**
* 创建线程进行下载操作
*
*/
public static final String DOWNLOAD_PATH = Environment
.getExternalStorageDirectory().getAbsolutePath() + "/downloads/";
private class InitThread extends Thread {
private FileInfo mFileInfo = null;
public InitThread(FileInfo mFileInfo) {
this.mFileInfo = mFileInfo;
}
@Override
public void run() {
//获取conn
HttpURLConnection connection = null;
RandomAccessFile raf = null;
try {
// 连接网络文件
URL url = new URL(mFileInfo.getUrl());
//打开conn链接
connection = (HttpURLConnection) url.openConnection();
connection.setConnectTimeout(5000);
connection.setRequestMethod("GET");
int length = -1;
if (connection.getResponseCode() == HttpStatus.SC_OK) {
// 获得文件的长度
length = connection.getContentLength();
}
if (length <= 0) {
return;
}
File dir = new File(DOWNLOAD_PATH);
if (!dir.exists()) {
dir.mkdir();
}
// 在本地创建文件
File file = new File(dir, mFileInfo.getFileName());
raf = new RandomAccessFile(file, "rwd");
// 设置文件长度
raf.setLength(length);
mFileInfo.setLength(length);
//obtainMessage(int what, Object obj)，准备完毕发送消息通知进行下载操作
mHandler.obtainMessage(MSG_INIT, mFileInfo).sendToTarget();
} catch (Exception e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.disconnect();
}
if (raf != null) {
try {
raf.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}
@Override
public IBinder onBind(Intent intent) {
return null;
}
}
DownloadTask
package com.download.services;
import java.io.File;
import java.io.InputStream;
import java.io.RandomAccessFile;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.util.List;
import org.apache.http.HttpStatus;
import android.R.integer;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import android.widget.Toast;
import com.download.app.MainActivity;
import com.download.db.ThreadDAO;
import com.download.db.ThreadDAOImpl;
import com.download.entities.FileInfo;
import com.download.entities.ThreadInfo;
public class DownloadTask {
private Context mContext = null;
private FileInfo mFileInfo = null;
private ThreadDAO mDao = null;
private int mFinised = 0;
public boolean isPause = false;
public DownloadTask(Context mContext, FileInfo mFileInfo) {
this.mContext = mContext;
this.mFileInfo = mFileInfo;
mDao = new ThreadDAOImpl(mContext);
}
public void downLoad() {
// 读取数据库的线程信息
List<ThreadInfo> threads = mDao.getThreads(mFileInfo.getUrl());
ThreadInfo threadInfo = null;
if (0 == threads.size()) {
// 初始化线程信息对象---ThreadInfo(int id, String url, int start, int end, int finished)
threadInfo = new ThreadInfo(0, mFileInfo.getUrl(), 0,
mFileInfo.getLength(), 0);
} else {
threadInfo = threads.get(0);
}
// 创建子线程进行下载
new DownloadThread(threadInfo).start();
}
/**
* 下载线程
*/
private class DownloadThread extends Thread {
private ThreadInfo mThreadInfo = null;
public DownloadThread(ThreadInfo mInfo) {
this.mThreadInfo = mInfo;
}
@Override
public void run() {
// 向数据库插入线程信息
if (!mDao.isExists(mThreadInfo.getUrl(), mThreadInfo.getId())) {
mDao.insertThread(mThreadInfo);
}
HttpURLConnection connection = null;
RandomAccessFile raf = null;
InputStream inputStream = null;
try {
URL url = new URL(mThreadInfo.getUrl());
connection = (HttpURLConnection) url.openConnection();
connection.setConnectTimeout(5000);
connection.setRequestMethod("GET");
// 设置下载位置
int start = mThreadInfo.getStart() + mThreadInfo.getFinished();
connection.setRequestProperty("Range", "bytes=" + start + "-"
+ mThreadInfo.getEnd());
// 设置文件写入位置
File file = new File(DownloadService.DOWNLOAD_PATH,
mFileInfo.getFileName());
raf = new RandomAccessFile(file, "rwd");
raf.seek(start);
Intent intent = new Intent();
intent.setAction(DownloadService.ACTION_UPDATE);
mFinised += mThreadInfo.getFinished();
// 开始下载
if (connection.getResponseCode() == HttpStatus.SC_PARTIAL_CONTENT) {
// 读取数据
inputStream = connection.getInputStream();
byte buf[] = new byte[1024 << 2];
int len = -1;
long time = System.currentTimeMillis();
while ((len = inputStream.read(buf)) != -1) {
// 写入文件
raf.write(buf, 0, len);
// 把下载进度发送广播给Activity
mFinised += len;
if (System.currentTimeMillis() - time > 500) {
time = System.currentTimeMillis();
intent.putExtra("finished", mFinised * 100
/ mThreadInfo.getEnd());
//发送广播
mContext.sendBroadcast(intent);
}
// 在下载暂停时，保存下载进度
if (isPause) {
mDao.updateThread(mThreadInfo.getUrl(),
mThreadInfo.getId(), mFinised);
return;
}
}
// 删除线程信息
mDao.deleteThread(mThreadInfo.getUrl(), mThreadInfo.getId());
Log.i("DownloadTask", "下载完毕");
//发送消息，通知下载完毕即可
MainActivity.mMainActivity.handler.sendEmptyMessage(0);
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (connection != null) {
connection.disconnect();
}
if (raf != null) {
raf.close();
}
if (inputStream != null) {
inputStream.close();
}
} catch (Exception e2) {
e2.printStackTrace();
}
}
}
}
}