http://blog.csdn.net/shimiso/article/details/6763986
多线程断点续传下载,这在实际项目中很常用.
main.xml:
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:orientation="vertical"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- >
- <EditText
- android:layout_width="match_parent"
- android:layout_height="wrap_content"
- android:id="@+id/editText"
- android:text="http://gongxue.cn/yingyinkuaiche/UploadFiles_9323/201008/2010082909434077.mp3"
- />
- <LinearLayout
- android:orientation="horizontal"
- android:layout_width="match_parent"
- android:layout_height="wrap_content"
- >
- <Button
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:id="@+id/downButton"
- android:text="Download"
- />
- <Button
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:id="@+id/pauseButton"
- android:enabled="false"
- android:text="Pause"
- />
- </LinearLayout>
- <ProgressBar
- android:layout_width="match_parent"
- android:layout_height="18dp"
- style="?android:attr/progressBarStyleHorizontal"
- android:id="@+id/progressBar"
- />
- <TextView
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:id="@+id/textView"
- android:gravity="center"
- />
- </LinearLayout>
String.xml:
- <?xml version="1.0" encoding="utf-8"?>
- <resources>
- <string name="hello">Hello World, Main!</string>
- <string name="app_name">多线程断点续传下载</string>
- </resources>
AndroidManifest.xml:
- <?xml version="1.0" encoding="utf-8"?>
- <manifest xmlns:android="http://schemas.android.com/apk/res/android"
- package="sms.multithreaddownload"
- android:versionCode="1"
- android:versionName="1.0">
- <application android:icon="@drawable/icon" android:label="@string/app_name">
- <activity android:name=".Main"
- android:label="@string/app_name">
- <intent-filter>
- <action android:name="android.intent.action.MAIN" />
- <category android:name="android.intent.category.LAUNCHER" />
- </intent-filter>
- </activity>
- <uses-library android:name="android.test.runner" />
- </application>
- <uses-sdk android:minSdkVersion="8" />
- <instrumentation
- android:targetPackage="sms.multithreaddownload"
- android:name="android.test.InstrumentationTestRunner" />
- <!-- 访问网络的权限 -->
- <uses-permission android:name="android.permission.INTERNET"/>
- <!-- SDCard写数据的权限 -->
- <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
- </manifest>
activity程序:
- package sms.multithreaddownload;
- import java.io.File;
- import sms.multithreaddownload.bean.DownloadListener;
- import sms.multithreaddownload.service.DownloadService;
- 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.view.View.OnClickListener;
- import android.widget.Button;
- import android.widget.EditText;
- import android.widget.ProgressBar;
- import android.widget.TextView;
- import android.widget.Toast;
- public class Main extends Activity {
- private EditText path;
- private TextView progress;
- private ProgressBar progressBar;
- private Handler handler = new UIHandler();
- private DownloadService servcie;
- private Button downButton;
- private Button pauseButton;
- private final class UIHandler extends Handler {
- @Override
- public void handleMessage(Message msg) {
- switch (msg.what) {
- case 1:
- int downloaded_size = msg.getData().getInt("size");
- progressBar.setProgress(downloaded_size);
- int result = (int) ((float) downloaded_size / progressBar.getMax() * 100);
- progress.setText(result + "%");
- if (progressBar.getMax() == progressBar.getProgress()) {
- Toast.makeText(getApplicationContext(), "下载完成", Toast.LENGTH_LONG).show();
- }
- }
- }
- }
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- path = (EditText) this.findViewById(R.id.editText);
- progress = (TextView) this.findViewById(R.id.textView);
- progressBar = (ProgressBar) this.findViewById(R.id.progressBar);
- downButton = (Button) this.findViewById(R.id.downButton);
- pauseButton = (Button) this.findViewById(R.id.pauseButton);
- downButton.setOnClickListener(new DownloadButton());
- pauseButton.setOnClickListener(new PauseButton());
- }
- private final class DownloadButton implements View.OnClickListener {
- @Override
- public void onClick(View v) {
- DownloadTask task;
- try {
- task = new DownloadTask(path.getText().toString());
- servcie.isPause = false;
- v.setEnabled(false);
- pauseButton.setEnabled(true);
- new Thread(task).start();
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- }
- public class PauseButton implements OnClickListener {
- @Override
- public void onClick(View v) {
- servcie.isPause = true;
- v.setEnabled(false);
- downButton.setEnabled(true);
- }
- }
- public void pause(View v) {
- }
- private final class DownloadTask implements Runnable {
- public DownloadTask(String target) throws Exception {
- if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
- File destination = Environment.getExternalStorageDirectory();
- servcie = new DownloadService(target, destination, 3, getApplicationContext());
- progressBar.setMax(servcie.fileSize);
- } else {
- Toast.makeText(getApplicationContext(), "SD卡不存在或写保护!", Toast.LENGTH_LONG).show();
- }
- }
- @Override
- public void run() {
- try {
- servcie.download(new DownloadListener() {
- @Override
- public void onDownload(int downloaded_size) {
- Message message = new Message();
- message.what = 1;
- message.getData().putInt("size", downloaded_size);
- handler.sendMessage(message);
- }
- });
- } catch (Exception e) {
- e.printStackTrace();
- }
- }
- }
- }
工具类:
- package sms.multithreaddownload.bean;
- import android.content.Context;
- import android.database.sqlite.SQLiteDatabase;
- import android.database.sqlite.SQLiteOpenHelper;
- public class DBHelper extends SQLiteOpenHelper {
- public DBHelper(Context context) {
- super(context, "MultiDownLoad.db", null, 1);
- }
- @Override
- public void onCreate(SQLiteDatabase db) {
- db.execSQL("CREATE TABLE fileDownloading(_id integer primary key autoincrement,downPath varchar(100),threadId INTEGER,downLength INTEGER)");
- }
- @Override
- public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
- // TODO Auto-generated method stub
- }
- }
- package sms.multithreaddownload.bean;
- public interface DownloadListener {
- public void onDownload(int downloaded_size);
- }
- package sms.multithreaddownload.bean;
- import java.io.File;
- import java.io.InputStream;
- import java.io.RandomAccessFile;
- import java.net.HttpURLConnection;
- import java.net.URL;
- import sms.multithreaddownload.service.DownloadService;
- import android.util.Log;
- public final class MultiThreadDownload implements Runnable {
- public int id;
- private RandomAccessFile savedFile;
- private String path;
- /* 当前已下载量 */
- public int currentDownloadSize = 0;
- /* 下载状态 */
- public boolean finished;
- /* 用于监视下载状态 */
- private final DownloadService downloadService;
- /* 线程下载任务的起始点 */
- public int start;
- /* 线程下载任务的结束点 */
- private int end;
- public MultiThreadDownload(int id, File savedFile, int block, String path, Integer downlength, DownloadService downloadService) throws Exception {
- this.id = id;
- this.path = path;
- if (downlength != null) this.currentDownloadSize = downlength;
- this.savedFile = new RandomAccessFile(savedFile, "rwd");
- this.downloadService = downloadService;
- start = id * block + currentDownloadSize;
- end = (id + 1) * block;
- }
- @Override
- public void run() {
- try {
- HttpURLConnection conn = (HttpURLConnection) new URL(path).openConnection();
- conn.setConnectTimeout(5000);
- conn.setRequestMethod("GET");
- conn.setRequestProperty("Range", "bytes=" + start + "-" + end); // 设置获取数据的范围
- InputStream in = conn.getInputStream();
- byte[] buffer = new byte[1024];
- int len = 0;
- savedFile.seek(start);
- while (!downloadService.isPause && (len = in.read(buffer)) != -1) {
- savedFile.write(buffer, 0, len);
- currentDownloadSize += len;
- }
- savedFile.close();
- in.close();
- conn.disconnect();
- if (!downloadService.isPause) Log.i(DownloadService.TAG, "Thread " + (this.id + 1) + "finished");
- finished = true;
- } catch (Exception e) {
- e.printStackTrace();
- throw new RuntimeException("File downloading error!");
- }
- }
- }
service类:
- package sms.multithreaddownload.service;
- import java.io.File;
- import java.io.RandomAccessFile;
- import java.net.HttpURLConnection;
- import java.net.URL;
- import java.util.HashMap;
- import java.util.List;
- import java.util.Map;
- import java.util.Map.Entry;
- import java.util.UUID;
- import java.util.concurrent.ConcurrentHashMap;
- import java.util.regex.Matcher;
- import java.util.regex.Pattern;
- import sms.multithreaddownload.bean.DBHelper;
- import sms.multithreaddownload.bean.DownloadListener;
- import sms.multithreaddownload.bean.MultiThreadDownload;
- import android.content.Context;
- import android.database.Cursor;
- import android.database.sqlite.SQLiteDatabase;
- public class DownloadService {
- public static final String TAG = "tag";
- /* 用于查询数据库 */
- private DBHelper dbHelper;
- /* 要下载的文件大小 */
- public int fileSize;
- /* 每条线程需要下载的数据量 */
- private int block;
- /* 保存文件地目录 */
- private File savedFile;
- /* 下载地址 */
- private String path;
- /* 是否停止下载 */
- public boolean isPause;
- /* 线程数 */
- private MultiThreadDownload[] threads;
- /* 各线程已经下载的数据量 */
- private Map<Integer, Integer> downloadedLength = new ConcurrentHashMap<Integer, Integer>();
- public DownloadService(String target, File destination, int thread_size, Context context) throws Exception {
- dbHelper = new DBHelper(context);
- this.threads = new MultiThreadDownload[thread_size];
- this.path = target;
- URL url = new URL(target);
- HttpURLConnection conn = (HttpURLConnection) url.openConnection();
- conn.setConnectTimeout(5000);
- conn.setRequestMethod("GET");
- if (conn.getResponseCode() != 200) {
- throw new RuntimeException("server no response!");
- }
- fileSize = conn.getContentLength();
- if (fileSize <= 0) {
- throw new RuntimeException("file is incorrect!");
- }
- String fileName = getFileName(conn);
- if (!destination.exists()) destination.mkdirs();
- // 构建一个同样大小的文件
- this.savedFile = new File(destination, fileName);
- RandomAccessFile doOut = new RandomAccessFile(savedFile, "rwd");
- doOut.setLength(fileSize);
- doOut.close();
- conn.disconnect();
- // 计算每条线程需要下载的数据长度
- this.block = fileSize % thread_size == 0 ? fileSize / thread_size : fileSize / thread_size + 1;
- // 查询已经下载的记录
- downloadedLength = this.getDownloadedLength(path);
- }
- private Map<Integer, Integer> getDownloadedLength(String path) {
- SQLiteDatabase db = dbHelper.getReadableDatabase();
- String sql = "SELECT threadId,downLength FROM fileDownloading WHERE downPath=?";
- Cursor cursor = db.rawQuery(sql, new String[] { path });
- Map<Integer, Integer> data = new HashMap<Integer, Integer>();
- while (cursor.moveToNext()) {
- data.put(cursor.getInt(0), cursor.getInt(1));
- }
- db.close();
- return data;
- }
- private String getFileName(HttpURLConnection conn) {
- String fileName = path.substring(path.lastIndexOf("/") + 1, path.length());
- if (fileName == null || "".equals(fileName.trim())) {
- String content_disposition = null;
- for (Entry<String, List<String>> entry : conn.getHeaderFields().entrySet()) {
- if ("content-disposition".equalsIgnoreCase(entry.getKey())) {
- content_disposition = entry.getValue().toString();
- }
- }
- try {
- Matcher matcher = Pattern.compile(".*filename=(.*)").matcher(content_disposition);
- if (matcher.find()) fileName = matcher.group(1);
- } catch (Exception e) {
- fileName = UUID.randomUUID().toString() + ".tmp"; // 默认名
- }
- }
- return fileName;
- }
- public void download(DownloadListener listener) throws Exception {
- this.deleteDownloading(); // 先删除上次的记录,再重新添加
- for (int i = 0; i < threads.length; i++) {
- threads[i] = new MultiThreadDownload(i, savedFile, block, path, downloadedLength.get(i), this);
- new Thread(threads[i]).start();
- }
- this.saveDownloading(threads);
- while (!isFinish(threads)) {
- Thread.sleep(900);
- if (listener != null) listener.onDownload(getDownloadedSize(threads));
- this.updateDownloading(threads);
- }
- if (!this.isPause) this.deleteDownloading();// 完成下载之后删除本次下载记录
- }
- private void saveDownloading(MultiThreadDownload[] threads) {
- SQLiteDatabase db = dbHelper.getWritableDatabase();
- try {
- db.beginTransaction();
- for (MultiThreadDownload thread : threads) {
- String sql = "INSERT INTO fileDownloading(downPath,threadId,downLength) values(?,?,?)";
- db.execSQL(sql, new Object[] { path, thread.id, 0 });
- }
- db.setTransactionSuccessful();
- } finally {
- db.endTransaction();
- db.close();
- }
- }
- private void deleteDownloading() {
- SQLiteDatabase db = dbHelper.getWritableDatabase();
- String sql = "DELETE FROM fileDownloading WHERE downPath=?";
- db.execSQL(sql, new Object[] { path });
- db.close();
- }
- private void updateDownloading(MultiThreadDownload[] threads) {
- SQLiteDatabase db = dbHelper.getWritableDatabase();
- try {
- db.beginTransaction();
- for (MultiThreadDownload thread : threads) {
- String sql = "UPDATE fileDownloading SET downLength=? WHERE threadId=? AND downPath=?";
- db.execSQL(sql, new String[] { thread.currentDownloadSize + "", thread.id + "", path });
- }
- db.setTransactionSuccessful();
- } finally {
- db.endTransaction();
- db.close();
- }
- }
- private int getDownloadedSize(MultiThreadDownload[] threads) {
- int sum = 0;
- for (int len = threads.length, i = 0; i < len; i++) {
- sum += threads[i].currentDownloadSize;
- }
- return sum;
- }
- private boolean isFinish(MultiThreadDownload[] threads) {
- try {
- for (int len = threads.length, i = 0; i < len; i++) {
- if (!threads[i].finished) {
- return false;
- }
- }
- return true;
- } catch (Exception e) {
- return false;
- }
- }
- }
运行效果: