让我们看一下代码的实现方法。
- package com.smart.db;
- 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
getData(String path){ - SQLiteDatabase db = openHelper.getReadableDatabase();
- Cursor cursor = db.rawQuery("select threadid, downlength from SmartFileDownlog where downpath=?", new String[]{path});
- Map
data = new HashMap (); - 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
map){//int threadid, int position - SQLiteDatabase db = openHelper.getWritableDatabase();
- db.beginTransaction();
- try{
- for(Map.Entry
entry : map.entrySet()){ - db.execSQL("insert into SmartFileDownlog(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
map){ - SQLiteDatabase db = openHelper.getWritableDatabase();
- db.beginTransaction();
- try{
- for(Map.Entry
entry : map.entrySet()){ - db.execSQL("update SmartFileDownlog 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 SmartFileDownlog where downpath=?", new Object[]{path});
- db.close();
- }
- }
- package com.smart.impl;
- 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 android.content.Context;
- import android.util.Log;
- import com.smart.db.FileService;
- /**
- * 文件下载器
- * @author lihuoming@sohu.com
- */
- public class SmartFileDownloader {
- private static final String TAG = "SmartFileDownloader";
- 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 SmartDownloadThread[] threads;
- /* 本地保存文件 */
- private File saveFile;
- /* 缓存各线程下载的长度*/
- private Map
data = new ConcurrentHashMap (); - /* 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 void update(int threadId, int pos) {
- this.data.put(threadId, pos);
- }
- /**
- * 保存记录文件
- */
- protected synchronized void saveLogFile() {
- 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 SmartFileDownloader(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 SmartDownloadThread[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);
- this.saveFile = new File(fileSaveDir, filename);/* 保存文件 */
- Map
logdata = fileService.getData(downloadUrl); - if(logdata.size()>0){
- for(Map.Entry
entry : logdata.entrySet()) - data.put(entry.getKey(), entry.getValue());
- }
- this.block = (this.fileSize % this.threads.length)==0? this.fileSize / this.threads.length : this.fileSize / this.threads.length + 1;
- if(this.data.size()==this.threads.length){
- 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);
- }
- }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(SmartDownloadProgressListener 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();//清除数据
- for (int i = 0; i < this.threads.length; i++) {
- this.data.put(i+1, 0);
- }
- }
- for (int i = 0; i < this.threads.length; i++) {
- int downLength = this.data.get(i+1);
- if(downLength < this.block && this.downloadSize
- this.threads = new SmartDownloadThread(this, url, this.saveFile, this.block, this.data.get(i+1), i+1);
- this.threads.setPriority(7);
- this.threads.start();
- }else{
- this.threads = null;
- }
- }
- this.fileService.save(this.downloadUrl, this.data);
- boolean notFinish = true;//下载未完成
- while (notFinish) {// 循环判断是否下载完毕
- Thread.sleep(900);
- notFinish = false;//假定下载完成
- for (int i = 0; i < this.threads.length; i++){
- if (this.threads != null && !this.threads.isFinish()) {
- notFinish = true;//下载没有完成
- if(this.threads.getDownLength() == -1){//如果下载失败,再重新下载
- this.threads = new SmartDownloadThread(this, url, this.saveFile, this.block, this.data.get(i+1), i+1);
- this.threads.setPriority(7);
- this.threads.start();
- }
- }
- }
- if(listener!=null) listener.onDownloadSize(this.downloadSize);
- }
- 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
getHttpResponseHeader(HttpURLConnection http) { - Map
header = new LinkedHashMap (); - 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
header = getHttpResponseHeader(http); - for(Map.Entry
entry : header.entrySet()){ - String key = entry.getKey()!=null ? entry.getKey()+ ":" : "";
- print(key+ entry.getValue());
- }
- }
- //打印日志
- private static void print(String msg){
- Log.i(TAG, msg);
- }
- }
- package com.smart.impl;
- 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 SmartDownloadThread extends Thread {
- private static final String TAG = "SmartDownloadThread";
- 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 SmartFileDownloader downloader;
- public SmartDownloadThread(SmartFileDownloader 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.saveLogFile();
- 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;
- }
- }
- package com.smart.activoty.download;
- import java.io.File;
- 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;
- import com.smart.impl.SmartDownloadProgressListener;
- import com.smart.impl.SmartFileDownloader;
- public class SmartDownloadActivity extends Activity {
- private ProgressBar downloadbar;
- private EditText pathText;
- private TextView resultView;
- private Handler handler = new Handler(){
- @Override//信息
- public void handleMessage(Message msg) {
- switch (msg.what) {
- case 1:
- int size = msg.getData().getInt("size");
- downloadbar.setProgress(size);
- float result = (float)downloadbar.getProgress()/ (float)downloadbar.getMax();
- int p = (int)(result*100);
- resultView.setText(p+"%");
- if(downloadbar.getProgress()==downloadbar.getMax())
- Toast.makeText(SmartDownloadActivity.this, R.string.success, 1).show();
- break;
- case -1:
- Toast.makeText(SmartDownloadActivity.this, R.string.error, 1).show();
- break;
- }
- }
- };
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
- Button button = (Button)this.findViewById(R.id.button);
- downloadbar = (ProgressBar)this.findViewById(R.id.downloadbar);
- pathText = (EditText)this.findViewById(R.id.path);
- resultView = (TextView)this.findViewById(R.id.result);
- button.setOnClickListener(new View.OnClickListener() {
- @Override
- public void onClick(View v) {
- String path = pathText.getText().toString();
- if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
- File dir = Environment.getExternalStorageDirectory();//文件保存目录
- download(path, dir);
- }else{
- Toast.makeText(SmartDownloadActivity.this, R.string.sdcarderror, 1).show();
- }
- }
- });
- }
- //对于UI控件的更新只能由主线程(UI线程)负责,如果在非UI线程更新UI控件,更新的结果不会反映在屏幕上,某些控件还会出错
- private void download(final String path, final File dir){
- new Thread(new Runnable() {
- @Override
- public void run() {
- try {
- SmartFileDownloader loader = new SmartFileDownloader(SmartDownloadActivity.this, path, dir, 3);
- int length = loader.getFileSize();//获取文件的长度
- downloadbar.setMax(length);
- loader.download(new SmartDownloadProgressListener(){
- @Override
- public void onDownloadSize(int size) {//可以实时得到文件下载的长度
- Message msg = new Message();
- msg.what = 1;
- msg.getData().putInt("size", size);
- handler.sendMessage(msg);
- }});
- } catch (Exception e) {
- Message msg = new Message();//信息提示
- msg.what = -1;
- msg.getData().putString("error", "下载失败");//如果下载错误,显示提示失败!
- handler.sendMessage(msg);
- }
- }
- }).start();//开始
- }
- }
名称栏目:Android多任务多线程断点下载
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