最近做一個文件上傳和下載的應用對文件上傳和下載進行了一個完整的流程分析

以來是方便自己對文件上傳和下載的理解，而來便于團隊內(nèi)部的分享

故而做了幾張圖，將整體的流程都畫下來，便于大家的理解和分析，如果有不完善的地方希望

大家多提意見，

由于參考了網(wǎng)上許多的資料，特此感謝

?

首先是文件上傳，這個要用到服務(wù)器

關(guān)鍵代碼

FileServer.java：

import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PushbackInputStream; import java.io.RandomAccessFile; import java.net.ServerSocket; import java.net.Socket; import java.text.SimpleDateFormat; import java.util.Date; import java.util.HashMap; import java.util.Map; import java.util.Properties; import java.util.Set; import java.util.concurrent.ExecutorService; import java.util.concurrent.Executors;import util.FileLogInfo; import util.StreamTool;public class FileServer {private ExecutorService executorService;//線程池private int port;//監(jiān)聽端口private boolean quit = false;//退出private ServerSocket server;private Map<Long, FileLogInfo> datas = new HashMap<Long, FileLogInfo>();//存放斷點數(shù)據(jù),以后改為數(shù)據(jù)庫存放public FileServer(int port){this.port = port;//創(chuàng)建線程池，池中具有(cpu個數(shù)*50)條線程executorService = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors() * 50);}/*** 退出*/public void quit(){this.quit = true;try {server.close();}catch (IOException e) {e.printStackTrace();}}/*** 啟動服務(wù)* @throws Exception*/public void start() throws Exception{server = new ServerSocket(port);//實現(xiàn)端口監(jiān)聽while(!quit){try {Socket socket = server.accept();executorService.execute(new SocketTask(socket));//為支持多用戶并發(fā)訪問，采用線程池管理每一個用戶的連接請求}catch (Exception e) {e.printStackTrace();}}}private final class SocketTask implements Runnable{private Socket socket = null;public SocketTask(Socket socket) {this.socket = socket;}@Overridepublic void run() {try {System.out.println("FileServer accepted connection "+ socket.getInetAddress()+ ":"+ socket.getPort());//得到客戶端發(fā)來的第一行協(xié)議數(shù)據(jù)：Content-Length=143253434;filename=xxx.3gp;sourceid=//如果用戶初次上傳文件，sourceid的值為空。InputStream inStream = socket.getInputStream();String head = StreamTool.readLine(inStream);System.out.println("FileServer head:"+head);if(head!=null){//下面從協(xié)議數(shù)據(jù)中提取各項參數(shù)值String[] items = head.split(";");String filelength = items[0].substring(items[0].indexOf("=")+1);String filename = items[1].substring(items[1].indexOf("=")+1);String sourceid = items[2].substring(items[2].indexOf("=")+1); //生成資源id，如果需要唯一性，可以采用UUIDlong id = System.currentTimeMillis();FileLogInfo log = null;if(sourceid!=null && !"".equals(sourceid)){id = Long.valueOf(sourceid);//查找上傳的文件是否存在上傳記錄log = find(id);}File file = null;int position = 0;//如果上傳的文件不存在上傳記錄,為文件添加跟蹤記錄if(log==null){//設(shè)置存放的位置與當前應用的位置有關(guān)File dir = new File("c:/temp/");if(!dir.exists()) dir.mkdirs();file = new File(dir, filename);//如果上傳的文件發(fā)生重名，然后進行改名if(file.exists()){filename = filename.substring(0, filename.indexOf(".")-1)+ dir.listFiles().length+ filename.substring(filename.indexOf("."));file = new File(dir, filename);}save(id, file);}// 如果上傳的文件存在上傳記錄,讀取上次的斷點位置else{System.out.println("FileServer have exits log not null");//從上傳記錄中得到文件的路徑file = new File(log.getPath());if(file.exists()){File logFile = new File(file.getParentFile(), file.getName()+".log");if(logFile.exists()){Properties properties = new Properties();properties.load(new FileInputStream(logFile));//讀取斷點位置position = Integer.valueOf(properties.getProperty("length"));}}}//***************************上面是對協(xié)議頭的處理，下面正式接收數(shù)據(jù)***************************************//向客戶端請求傳輸數(shù)據(jù)OutputStream outStream = socket.getOutputStream();String response = "sourceid="+ id+ ";position="+ position+ "%";//服務(wù)器收到客戶端的請求信息后，給客戶端返回響應信息：sourceid=1274773833264;position=position//sourceid由服務(wù)生成，唯一標識上傳的文件，position指示客戶端從文件的什么位置開始上傳 outStream.write(response.getBytes());RandomAccessFile fileOutStream = new RandomAccessFile(file, "rwd");//設(shè)置文件長度if(position==0) fileOutStream.setLength(Integer.valueOf(filelength));//移動文件指定的位置開始寫入數(shù)據(jù) fileOutStream.seek(position);byte[] buffer = new byte[1024];int len = -1;int length = position;//從輸入流中讀取數(shù)據(jù)寫入到文件中，并將已經(jīng)傳入的文件長度寫入配置文件，實時記錄文件的最后保存位置while( (len=inStream.read(buffer)) != -1){fileOutStream.write(buffer, 0, len);length += len;Properties properties = new Properties();properties.put("length", String.valueOf(length));FileOutputStream logFile = new FileOutputStream(new File(file.getParentFile(), file.getName()+".log"));//實時記錄文件的最后保存位置properties.store(logFile, null);logFile.close();}//如果長傳長度等于實際長度則表示長傳成功if(length==fileOutStream.length()){delete(id);}fileOutStream.close(); inStream.close();outStream.close();file = null;}}catch (Exception e) {e.printStackTrace();}finally{try{if(socket!=null && !socket.isClosed()) socket.close();} catch (IOException e){e.printStackTrace();}}}}/*** 查找在記錄中是否有sourceid的文件* @param sourceid* @return*/public FileLogInfo find(Long sourceid){return datas.get(sourceid);}/*** 保存上傳記錄，日后可以改成通過數(shù)據(jù)庫存放* @param id* @param saveFile*/public void save(Long id, File saveFile){System.out.println("save logfile "+id);datas.put(id, new FileLogInfo(id, saveFile.getAbsolutePath()));}/*** 當文件上傳完畢，刪除記錄* @param sourceid*/public void delete(long sourceid){System.out.println("delete logfile "+sourceid);if(datas.containsKey(sourceid)) datas.remove(sourceid);}}

由于在上面的流程圖中已經(jīng)進行了詳細的分析，我在這兒就不講了，只是在存儲數(shù)據(jù)的時候服務(wù)器沒有用數(shù)據(jù)庫去存儲，這兒只是為了方便，所以要想測試斷點上傳，服務(wù)器是不能停的，否則數(shù)據(jù)就沒有了，在以后改進的時候應該用數(shù)據(jù)庫去存儲數(shù)據(jù)。

文件上傳客戶端

關(guān)鍵代碼：

UploadActivity.java

1 package com.hao; 2 3 import java.io.File; 4 import java.util.List; 5 6 import com.hao.upload.UploadThread; 7 import com.hao.upload.UploadThread.UploadProgressListener; 8 import com.hao.util.ConstantValues; 9 import com.hao.util.FileBrowserActivity; 10 11 import android.app.Activity; 12 import android.app.Dialog; 13 import android.app.ProgressDialog; 14 import android.content.DialogInterface; 15 import android.content.Intent; 16 import android.content.res.Resources; 17 import android.net.Uri; 18 import android.os.Bundle; 19 import android.os.Environment; 20 import android.os.Handler; 21 import android.os.Message; 22 import android.util.Log; 23 import android.view.View; 24 import android.view.View.OnClickListener; 25 import android.widget.Button; 26 import android.widget.TextView; 27 import android.widget.Toast; 28 /** 29 * 30 * @author Administrator 31 * 32 */ 33 public class UploadActivity extends Activity implements OnClickListener{ 34 private static final String TAG = "SiteFileFetchActivity"; 35 private Button download, upload, select_file; 36 private TextView info; 37 private static final int PROGRESS_DIALOG = 0; 38 private ProgressDialog progressDialog; 39 private UploadThread uploadThread; 40 private String uploadFilePath = null; 41 private String fileName; 42 /** Called when the activity is first created. */ 43 @Override 44 public void onCreate(Bundle savedInstanceState) { 45 super.onCreate(savedInstanceState); 46 setContentView(R.layout.upload); 47 initView(); 48 } 49 50 private void initView(){ 51 download = (Button) findViewById(R.id.download); 52 download.setOnClickListener(this); 53 upload = (Button) findViewById(R.id.upload); 54 upload.setOnClickListener(this); 55 info = (TextView) findViewById(R.id.info); 56 select_file = (Button) findViewById(R.id.select_file); 57 select_file.setOnClickListener(this); 58 } 59 60 @Override 61 protected void onActivityResult(int requestCode, int resultCode, Intent data) { 62 // TODO Auto-generated method stub 63 super.onActivityResult(requestCode, resultCode, data); 64 if (resultCode == RESULT_OK) { 65 if (requestCode == 1) { 66 Uri uri = data.getData(); // 接收用戶所選文件的路徑 67 info.setText("select: " + uri); // 在界面上顯示路徑 68 uploadFilePath = uri.getPath(); 69 int last = uploadFilePath.lastIndexOf("/"); 70 uploadFilePath = uri.getPath().substring(0, last+1); 71 fileName = uri.getLastPathSegment(); 72 } 73 } 74 } 75 76 protected Dialog onCreateDialog(int id) { 77 switch(id) { 78 case PROGRESS_DIALOG: 79 progressDialog = new ProgressDialog(UploadActivity.this); 80 progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL); 81 progressDialog.setButton("暫停", new DialogInterface.OnClickListener() { 82 @Override 83 public void onClick(DialogInterface dialog, int which) { 84 // TODO Auto-generated method stub 85 uploadThread.closeLink(); 86 dialog.dismiss(); 87 } 88 }); 89 progressDialog.setMessage("正在上傳..."); 90 progressDialog.setMax(100); 91 return progressDialog; 92 default: 93 return null; 94 } 95 } 96 97 /** 98 * 使用Handler給創(chuàng)建他的線程發(fā)送消息， 99 * 匿名內(nèi)部類 100 */ 101 private Handler handler = new Handler() 102 { 103 @Override 104 public void handleMessage(Message msg) 105 { 106 //獲得上傳長度的進度 107 int length = msg.getData().getInt("size"); 108 progressDialog.setProgress(length); 109 if(progressDialog.getProgress()==progressDialog.getMax())//上傳成功 110 { 111 progressDialog.dismiss(); 112 Toast.makeText(UploadActivity.this, getResources().getString(R.string.upload_over), 1).show(); 113 } 114 } 115 }; 116 117 @Override 118 public void onClick(View v) { 119 // TODO Auto-generated method stub 120 Resources r = getResources(); 121 switch(v.getId()){ 122 case R.id.select_file: 123 Intent intent = new Intent(); 124 //設(shè)置起始目錄和查找的類型 125 intent.setDataAndType(Uri.fromFile(new File("/sdcard")), "*/*");//"*/*"表示所有類型，設(shè)置起始文件夾和文件類型 126 intent.setClass(UploadActivity.this, FileBrowserActivity.class); 127 startActivityForResult(intent, 1); 128 break; 129 case R.id.download: 130 startActivity(new Intent(UploadActivity.this, SmartDownloadActivity.class)); 131 break; 132 case R.id.upload: 133 if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED))//判斷SDCard是否存在 134 { 135 if(uploadFilePath == null){ 136 Toast.makeText(UploadActivity.this, "還沒設(shè)置上傳文件", 1).show(); 137 } 138 System.out.println("uploadFilePath:"+uploadFilePath+" "+fileName); 139 //取得SDCard的目錄 140 File uploadFile = new File(new File(uploadFilePath), fileName); 141 Log.i(TAG, "filePath:"+uploadFile.toString()); 142 if(uploadFile.exists()) 143 { 144 showDialog(PROGRESS_DIALOG); 145 info.setText(uploadFile+" "+ConstantValues.HOST+":"+ConstantValues.PORT); 146 progressDialog.setMax((int) uploadFile.length());//設(shè)置長傳文件的最大刻度 147 uploadThread = new UploadThread(UploadActivity.this, uploadFile, ConstantValues.HOST, ConstantValues.PORT); 148 uploadThread.setListener(new UploadProgressListener() { 149 150 @Override 151 public void onUploadSize(int size) { 152 // TODO Auto-generated method stub 153 Message msg = new Message(); 154 msg.getData().putInt("size", size); 155 handler.sendMessage(msg); 156 } 157 }); 158 uploadThread.start(); 159 } 160 else 161 { 162 Toast.makeText(UploadActivity.this, "文件不存在", 1).show(); 163 } 164 } 165 else 166 { 167 Toast.makeText(UploadActivity.this, "SDCard不存在！", 1).show(); 168 } 169 break; 170 } 171 172 } 173 174 175 }

UploadThread.java

package com.hao.upload;import java.io.File; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.RandomAccessFile; import java.net.Socket;import android.content.Context; import android.util.Log;import com.hao.db.UploadLogService; import com.hao.util.StreamTool;public class UploadThread extends Thread {private static final String TAG = "UploadThread";/*需要上傳文件的路徑*/private File uploadFile;/*上傳文件服務(wù)器的IP地址*/private String dstName;/*上傳服務(wù)器端口號*/private int dstPort;/*上傳socket鏈接*/private Socket socket;/*存儲上傳的數(shù)據(jù)庫*/private UploadLogService logService; private UploadProgressListener listener;public UploadThread(Context context, File uploadFile, final String dstName,final int dstPort){this.uploadFile = uploadFile;this.dstName = dstName;this.dstPort = dstPort;logService = new UploadLogService(context);}public void setListener(UploadProgressListener listener) {this.listener = listener;}/*** 模擬斷開連接*/public void closeLink(){try{if(socket != null) socket.close();}catch(IOException e){e.printStackTrace();Log.e(TAG, "close socket fail");}}@Overridepublic void run() {// TODO Auto-generated method stubtry {// 判斷文件是否已有上傳記錄String souceid = logService.getBindId(uploadFile);// 構(gòu)造拼接協(xié)議String head = "Content-Length=" + uploadFile.length()+ ";filename=" + uploadFile.getName() + ";sourceid="+ (souceid == null ? "" : souceid) + "%";// 通過Socket取得輸出流socket = new Socket(dstName, dstPort);OutputStream outStream = socket.getOutputStream();outStream.write(head.getBytes());Log.i(TAG, "write to outStream");InputStream inStream = socket.getInputStream();// 獲取到字符流的id與位置String response = StreamTool.readLine(inStream);Log.i(TAG, "response:" + response);String[] items = response.split(";");String responseid = items[0].substring(items[0].indexOf("=") + 1);String position = items[1].substring(items[1].indexOf("=") + 1);// 代表原來沒有上傳過此文件，往數(shù)據(jù)庫添加一條綁定記錄if (souceid == null) {logService.save(responseid, uploadFile);}RandomAccessFile fileOutStream = new RandomAccessFile(uploadFile, "r");// 查找上次傳送的最終位置，并從這開始傳送 fileOutStream.seek(Integer.valueOf(position));byte[] buffer = new byte[1024];int len = -1;// 初始化上傳的數(shù)據(jù)長度int length = Integer.valueOf(position);while ((len = fileOutStream.read(buffer)) != -1) {outStream.write(buffer, 0, len);// 設(shè)置長傳數(shù)據(jù)長度length += len;listener.onUploadSize(length);}fileOutStream.close();outStream.close();inStream.close();socket.close();// 判斷上傳完則刪除數(shù)據(jù)if (length == uploadFile.length())logService.delete(uploadFile);} catch (Exception e) {e.printStackTrace();}}public interface UploadProgressListener{void onUploadSize(int size);} }

?下面是多線程下載

SmartDownloadActivity.java

1 package com.hao; 2 3 import java.io.File; 4 5 import com.hao.R; 6 import com.hao.R.id; 7 import com.hao.R.layout; 8 import com.hao.download.SmartFileDownloader; 9 import com.hao.download.SmartFileDownloader.SmartDownloadProgressListener; 10 import com.hao.util.ConstantValues; 11 12 import android.app.Activity; 13 import android.os.Bundle; 14 import android.os.Environment; 15 import android.os.Handler; 16 import android.os.Message; 17 import android.view.View; 18 import android.widget.Button; 19 import android.widget.ProgressBar; 20 import android.widget.TextView; 21 import android.widget.Toast; 22 23 /** 24 * 25 * @author Administrator 26 * 27 */ 28 public class SmartDownloadActivity extends Activity { 29 private ProgressBar downloadbar; 30 private TextView resultView; 31 private String path = ConstantValues.DOWNLOAD_URL; 32 SmartFileDownloader loader; 33 private Handler handler = new Handler() { 34 @Override 35 // 信息 36 public void handleMessage(Message msg) { 37 switch (msg.what) { 38 case 1: 39 int size = msg.getData().getInt("size"); 40 downloadbar.setProgress(size); 41 float result = (float) downloadbar.getProgress() / (float) downloadbar.getMax(); 42 int p = (int) (result * 100); 43 resultView.setText(p + "%"); 44 if (downloadbar.getProgress() == downloadbar.getMax()) 45 Toast.makeText(SmartDownloadActivity.this, "下載成功", 1).show(); 46 break; 47 case -1: 48 Toast.makeText(SmartDownloadActivity.this, msg.getData().getString("error"), 1).show(); 49 break; 50 } 51 52 } 53 }; 54 55 public void onCreate(Bundle savedInstanceState) { 56 super.onCreate(savedInstanceState); 57 setContentView(R.layout.download); 58 59 Button button = (Button) this.findViewById(R.id.button); 60 Button closeConn = (Button) findViewById(R.id.closeConn); 61 closeConn.setOnClickListener(new View.OnClickListener() { 62 63 @Override 64 public void onClick(View v) { 65 // TODO Auto-generated method stub 66 if(loader != null){ 67 finish(); 68 }else{ 69 Toast.makeText(SmartDownloadActivity.this, "還沒有開始下載，不能暫停", 1).show(); 70 } 71 } 72 }); 73 downloadbar = (ProgressBar) this.findViewById(R.id.downloadbar); 74 resultView = (TextView) this.findViewById(R.id.result); 75 resultView.setText(path); 76 button.setOnClickListener(new View.OnClickListener() { 77 @Override 78 public void onClick(View v) { 79 if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) { 80 download(path, ConstantValues.FILE_PATH); 81 } else { 82 Toast.makeText(SmartDownloadActivity.this, "沒有SDCard", 1).show(); 83 } 84 } 85 }); 86 } 87 88 // 對于UI控件的更新只能由主線程(UI線程)負責，如果在非UI線程更新UI控件，更新的結(jié)果不會反映在屏幕上，某些控件還會出錯 89 private void download(final String path, final File dir) { 90 new Thread(new Runnable() { 91 @Override 92 public void run() { 93 try { 94 loader = new SmartFileDownloader(SmartDownloadActivity.this, path, dir, 3); 95 int length = loader.getFileSize();// 獲取文件的長度 96 downloadbar.setMax(length); 97 loader.download(new SmartDownloadProgressListener() { 98 @Override 99 public void onDownloadSize(int size) {// 可以實時得到文件下載的長度 100 Message msg = new Message(); 101 msg.what = 1; 102 msg.getData().putInt("size", size); 103 handler.sendMessage(msg); 104 } 105 }); 106 } catch (Exception e) { 107 Message msg = new Message();// 信息提示 108 msg.what = -1; 109 msg.getData().putString("error", "下載失敗");// 如果下載錯誤，顯示提示失敗！ 110 handler.sendMessage(msg); 111 } 112 } 113 }).start();// 開始 114 115 } 116 }

這個單個的下載線程

SmartDownloadThread.java

package com.hao.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;/*** 線程下載* @author Administrator* */ public class SmartDownloadThread extends Thread {private static final String TAG = "SmartDownloadThread";private File saveFile;private URL downUrl;private int block;/* *下載開始位置 */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;}@Overridepublic void run() {if (downLength < block) {// 未下載完成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;// 開始位置int endPos = block * threadId - 1;// 結(jié)束位置http.setRequestProperty("Range", "bytes=" + startPos + "-" + endPos);// 設(shè)置獲取實體數(shù)據(jù)的范圍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);}/*** 下載是否完成* @return*/public boolean isFinish() {return finish;}/*** 已經(jīng)下載的內(nèi)容大小* @return 如果返回值為-1,代表下載失敗*/public long getDownLength() {return downLength;} }

總得下載線程

SmartFileDownloader.java

1 package com.hao.download; 2 3 import java.io.File; 4 import java.io.RandomAccessFile; 5 import java.net.HttpURLConnection; 6 import java.net.URL; 7 import java.util.LinkedHashMap; 8 import java.util.Map; 9 import java.util.UUID; 10 import java.util.concurrent.ConcurrentHashMap; 11 import java.util.regex.Matcher; 12 import java.util.regex.Pattern; 13 14 import com.hao.db.DownloadFileService; 15 16 import android.content.Context; 17 import android.util.Log; 18 19 /** 20 * 文件下載主程序 21 * @author Administrator 22 * 23 */ 24 public class SmartFileDownloader { 25 private static final String TAG = "SmartFileDownloader"; 26 private Context context; 27 private DownloadFileService fileService; 28 /* 已下載文件長度 */ 29 private int downloadSize = 0; 30 /* 原始文件長度 */ 31 private int fileSize = 0; 32 /*原始文件名*/ 33 private String fileName; 34 /* 線程數(shù) */ 35 private SmartDownloadThread[] threads; 36 /* 本地保存文件 */ 37 private File saveFile; 38 /* 緩存各線程下載的長度 */ 39 private Map<Integer, Integer> data = new ConcurrentHashMap<Integer, Integer>(); 40 /* 每條線程下載的長度 */ 41 private int block; 42 /* 下載路徑 */ 43 private String downloadUrl; 44 45 /** 46 * 獲取文件名 47 */ 48 public String getFileName(){ 49 return this.fileName; 50 } 51 /** 52 * 獲取線程數(shù) 53 */ 54 public int getThreadSize() { 55 return threads.length; 56 } 57 58 /** 59 * 獲取文件大小 60 * @return 61 */ 62 public int getFileSize() { 63 return fileSize; 64 } 65 66 /** 67 * 累計已下載大小 68 * @param size 69 */ 70 protected synchronized void append(int size) { 71 downloadSize += size; 72 } 73 74 /** 75 * 更新指定線程最后下載的位置 76 * @param threadId 線程id 77 * @param pos 最后下載的位置 78 */ 79 protected void update(int threadId, int pos) { 80 this.data.put(threadId, pos); 81 } 82 83 /** 84 * 保存記錄文件 85 */ 86 protected synchronized void saveLogFile() { 87 this.fileService.update(this.downloadUrl, this.data); 88 } 89 90 /** 91 * 構(gòu)建文件下載器 92 * @param downloadUrl 下載路徑 93 * @param fileSaveDir 文件保存目錄 94 * @param threadNum 下載線程數(shù) 95 */ 96 public SmartFileDownloader(Context context, String downloadUrl, 97 File fileSaveDir, int threadNum) { 98 try { 99 this.context = context; 100 this.downloadUrl = downloadUrl; 101 fileService = new DownloadFileService(this.context); 102 URL url = new URL(this.downloadUrl); 103 if (!fileSaveDir.exists()) fileSaveDir.mkdirs(); 104 this.threads = new SmartDownloadThread[threadNum]; 105 HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 106 conn.setConnectTimeout(5 * 1000); 107 conn.setRequestMethod("GET"); 108 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, */*"); 109 conn.setRequestProperty("Accept-Language", "zh-CN"); 110 conn.setRequestProperty("Referer", downloadUrl); 111 conn.setRequestProperty("Charset", "UTF-8"); 112 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)"); 113 conn.setRequestProperty("Connection", "Keep-Alive"); 114 conn.connect(); 115 printResponseHeader(conn); 116 if (conn.getResponseCode() == 200) { 117 this.fileSize = conn.getContentLength();// 根據(jù)響應獲取文件大小 118 if (this.fileSize <= 0) 119 throw new RuntimeException("Unkown file size "); 120 121 fileName = getFileName(conn); 122 this.saveFile = new File(fileSaveDir, fileName);/* 保存文件 */ 123 Map<Integer, Integer> logdata = fileService.getData(downloadUrl); 124 if (logdata.size() > 0) { 125 for (Map.Entry<Integer, Integer> entry : logdata.entrySet()) 126 data.put(entry.getKey(), entry.getValue()); 127 } 128 //劃分每個線程下載文件長度 129 this.block = (this.fileSize % this.threads.length) == 0 ? this.fileSize / this.threads.length 130 : this.fileSize / this.threads.length + 1; 131 if (this.data.size() == this.threads.length) { 132 for (int i = 0; i < this.threads.length; i++) { 133 this.downloadSize += this.data.get(i + 1); 134 } 135 print("已經(jīng)下載的長度" + this.downloadSize); 136 } 137 } else { 138 throw new RuntimeException("server no response "); 139 } 140 } catch (Exception e) { 141 print(e.toString()); 142 throw new RuntimeException("don't connection this url"); 143 } 144 } 145 146 /** 147 * 獲取文件名 148 */ 149 private String getFileName(HttpURLConnection conn) { 150 String filename = this.downloadUrl.substring(this.downloadUrl.lastIndexOf('/') + 1);//鏈接的最后一個/就是文件名 151 if (filename == null || "".equals(filename.trim())) {// 如果獲取不到文件名稱 152 for (int i = 0;; i++) { 153 String mine = conn.getHeaderField(i); 154 print("ConnHeader:"+mine+" "); 155 if (mine == null) 156 break; 157 if ("content-disposition".equals(conn.getHeaderFieldKey(i).toLowerCase())) { 158 Matcher m = Pattern.compile(".*filename=(.*)").matcher(mine.toLowerCase()); 159 if (m.find()) 160 return m.group(1); 161 } 162 } 163 filename = UUID.randomUUID() + ".tmp";// 默認取一個文件名 164 } 165 return filename; 166 } 167 168 /** 169 * 開始下載文件 170 * 171 * @param listener 172 * 監(jiān)聽下載數(shù)量的變化,如果不需要了解實時下載的數(shù)量,可以設(shè)置為null 173 * @return 已下載文件大小 174 * @throws Exception 175 */ 176 public int download(SmartDownloadProgressListener listener) 177 throws Exception { 178 try { 179 RandomAccessFile randOut = new RandomAccessFile(this.saveFile, "rw"); 180 if (this.fileSize > 0) 181 randOut.setLength(this.fileSize); 182 randOut.close(); 183 URL url = new URL(this.downloadUrl); 184 if (this.data.size() != this.threads.length) { 185 this.data.clear();// 清除數(shù)據(jù) 186 for (int i = 0; i < this.threads.length; i++) { 187 this.data.put(i + 1, 0); 188 } 189 } 190 for (int i = 0; i < this.threads.length; i++) { 191 int downLength = this.data.get(i + 1); 192 if (downLength < this.block && this.downloadSize < this.fileSize) { // 該線程未完成下載時,繼續(xù)下載 193 this.threads[i] = new SmartDownloadThread(this, url, 194 this.saveFile, this.block, this.data.get(i + 1), i + 1); 195 this.threads[i].setPriority(7); 196 this.threads[i].start(); 197 } else { 198 this.threads[i] = null; 199 } 200 } 201 this.fileService.save(this.downloadUrl, this.data); 202 boolean notFinish = true;// 下載未完成 203 while (notFinish) {// 循環(huán)判斷是否下載完畢 204 Thread.sleep(900); 205 notFinish = false;// 假定下載完成 206 for (int i = 0; i < this.threads.length; i++) { 207 if (this.threads[i] != null && !this.threads[i].isFinish()) { 208 notFinish = true;// 下載沒有完成 209 if (this.threads[i].getDownLength() == -1) {// 如果下載失敗,再重新下載 210 this.threads[i] = new SmartDownloadThread(this, 211 url, this.saveFile, this.block, this.data.get(i + 1), i + 1); 212 this.threads[i].setPriority(7); 213 this.threads[i].start(); 214 } 215 } 216 } 217 if (listener != null) 218 listener.onDownloadSize(this.downloadSize); 219 } 220 fileService.delete(this.downloadUrl); 221 } catch (Exception e) { 222 print(e.toString()); 223 throw new Exception("file download fail"); 224 } 225 return this.downloadSize; 226 } 227 228 /** 229 * 獲取Http響應頭字段 230 * 231 * @param http 232 * @return 233 */ 234 public static Map<String, String> getHttpResponseHeader( 235 HttpURLConnection http) { 236 Map<String, String> header = new LinkedHashMap<String, String>(); 237 for (int i = 0;; i++) { 238 String mine = http.getHeaderField(i); 239 if (mine == null) 240 break; 241 header.put(http.getHeaderFieldKey(i), mine); 242 } 243 return header; 244 } 245 246 /** 247 * 打印Http頭字段 248 * 249 * @param http 250 */ 251 public static void printResponseHeader(HttpURLConnection http) { 252 Map<String, String> header = getHttpResponseHeader(http); 253 for (Map.Entry<String, String> entry : header.entrySet()) { 254 String key = entry.getKey() != null ? entry.getKey() + ":" : ""; 255 print(key + entry.getValue()); 256 } 257 } 258 259 // 打印日志 260 private static void print(String msg) { 261 Log.i(TAG, msg); 262 } 263 264 public interface SmartDownloadProgressListener { 265 public void onDownloadSize(int size); 266 } 267 }

好了這里只是將主要的代碼分享出來，主要是為了了解他的基本流程，然后自己可以擴展，和優(yōu)化

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轉(zhuǎn)載于:https://www.cnblogs.com/cjt-java/archive/2012/06/24/2560457.html

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