Android 工具類

一、檢查網絡是否可用
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;


public class ConnectionUtil {
/**
* 檢查網絡是否可用
* @param context應用程序的上下文對象
* @return
*/
public static boolean isNetworkAvailable(Context context) {
ConnectivityManager connectivity = (ConnectivityManager) context
.getSystemService(Context.CONNECTIVITY_SERVICE);//獲取系統網絡連接管理器
if (connectivity == null) {//如果網絡管理器爲null
return false;  //返回false表明網絡無法連接
} else {
NetworkInfo[] info = connectivity.getAllNetworkInfo();//獲取所有的網絡連接對象
if (info != null) {//網絡信息不爲null時
for (int i = 0; i < info.length; i++) {//遍歷網路連接對象
if (info[i].isConnected()) {//當有一個網絡連接對象連接上網絡時
return true;  //返回true表明網絡連接正常
}
}
}
}
return false;  
}

public static void httpTest(final Context ctx,String title,String msg) {
if (!isNetworkAvailable(ctx)) {
AlertDialog.Builder builders = new AlertDialog.Builder(ctx);
builders.setTitle(title);
builders.setMessage(msg);
builders.setPositiveButton(android.R.string.ok,
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
//alert.dismiss();
}
});
AlertDialog alert = builders.create();
alert.show();
}
}

}

二、讀取流文件

StreamTool.java

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PushbackInputStream;


public class StreamTool {


public static void save(File file, byte[] data) throws Exception {
FileOutputStream outStream = new FileOutputStream(file);
outStream.write(data);
outStream.close();
}
 
public static String readLine(PushbackInputStream in) throws IOException {
char buf[] = new char[128];
int room = buf.length;
int offset = 0;
int c;
loop: while (true) {
switch (c = in.read()) {
case -1:
case '\n':
break loop;
case '\r':
int c2 = in.read();
if ((c2 != '\n') && (c2 != -1)) in.unread(c2);
break loop;
default:
if (--room < 0) {
char[] lineBuffer = buf;
buf = new char[offset + 128];
   room = buf.length - offset - 1;
   System.arraycopy(lineBuffer, 0, buf, 0, offset);
  
}
buf[offset++] = (char) c;
break;
}
}
if ((c == -1) && (offset == 0)) return null;
return String.copyValueOf(buf, 0, offset);
}
 
/**
* 讀取流
* @param inStream
* @return 字節數組
* @throws Exception
*/
public static byte[] readStream(InputStream inStream) throws Exception{
ByteArrayOutputStream outSteam = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = -1;
while( (len=inStream.read(buffer)) != -1){
outSteam.write(buffer, 0, len);
}
outSteam.close();
inStream.close();
return outSteam.toByteArray();
}
}

三、文件斷點上傳

MainActivity.java

import java.io.File;
import java.io.OutputStream;
import java.io.PushbackInputStream;
import java.io.RandomAccessFile;
import java.net.Socket;
import cn.itcast.service.UploadLogService;
import cn.itcast.utils.StreamTool;
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 MainActivity extends Activity {
    private EditText filenameText;
    private TextView resultView;
    private ProgressBar uploadbar;
    private UploadLogService service;
    private Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
uploadbar.setProgress(msg.getData().getInt("length"));
float num = (float)uploadbar.getProgress() / (float)uploadbar.getMax();
int result = (int)(num * 100);
resultView.setText(result + "%");
if(uploadbar.getProgress() == uploadbar.getMax()){
Toast.makeText(MainActivity.this, R.string.success, 1).show();
}
}
    };
    
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        service =  new UploadLogService(this);
        filenameText = (EditText)findViewById(R.id.filename);
        resultView = (TextView)findViewById(R.id.result);
        uploadbar = (ProgressBar)findViewById(R.id.uploadbar);
        Button button = (Button)findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
String filename = filenameText.getText().toString();
if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
File file = new File(Environment.getExternalStorageDirectory(), filename);
if(file.exists()){
uploadbar.setMax((int)file.length());
uploadFile(file);
}else{
Toast.makeText(MainActivity.this, R.string.notexsit, 1).show();
}
}else{
Toast.makeText(MainActivity.this, R.string.sdcarderror, 1).show();
}
}
});
    }


private void uploadFile(final File file) {
new Thread(new Runnable() {
public void run() {
try {
String sourceid = service.getBindId(file);
Socket socket = new Socket("192.168.1.100", 7878);//根據IP地址和端口不同更改
           OutputStream outStream = socket.getOutputStream(); 
           String head = "Content-Length="+ file.length() + ";filename="+ file.getName() 
             + ";sourceid="+(sourceid!=null ? sourceid : "")+"\r\n";
           outStream.write(head.getBytes());
           
           PushbackInputStream inStream = new PushbackInputStream(socket.getInputStream());
String response = StreamTool.readLine(inStream);
           String[] items = response.split(";");
String responseSourceid = items[0].substring(items[0].indexOf("=")+1);
String position = items[1].substring(items[1].indexOf("=")+1);
if(sourceid==null){//如果是第一次上傳文件，在數據庫中不存在該文件所綁定的資源id，入庫
service.save(responseSourceid, file);
}
RandomAccessFile fileOutStream = new RandomAccessFile(file, "r");
fileOutStream.seek(Integer.valueOf(position));
byte[] buffer = new byte[1024];
int len = -1;
int length = Integer.valueOf(position);
while( (len = fileOutStream.read(buffer)) != -1){
outStream.write(buffer, 0, len);
length += len;//累加已經上傳的數據長度
Message msg = new Message();
msg.getData().putInt("length", length);
handler.sendMessage(msg);
}
if(length == file.length()) service.delete(file);
fileOutStream.close();
outStream.close();
           inStream.close();
           socket.close();
       } catch (Exception e) {                    
         Toast.makeText(MainActivity.this, R.string.error, 1).show();
       }
}
}).start();
}
}

DBOpenHelper.java//數據庫

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;


public class DBOpenHelper extends SQLiteOpenHelper {


public DBOpenHelper(Context context) {
super(context, "itcast.db", null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE IF NOT EXISTS uploadlog (_id integer primary key autoincrement, path varchar(20), sourceid varchar(20))");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}

}

UploadLogService.java

import java.io.File;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;


public class UploadLogService {
private DBOpenHelper dbOpenHelper;

public UploadLogService(Context context){
dbOpenHelper = new DBOpenHelper(context);
}

public String getBindId(File file){
SQLiteDatabase db = dbOpenHelper.getReadableDatabase();
Cursor cursor = db.rawQuery("select sourceid from uploadlog where path=?", new String[]{file.getAbsolutePath()});
if(cursor.moveToFirst()){
return cursor.getString(0);
}
return null;
}

public void save(String sourceid, File file){
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
db.execSQL("insert into uploadlog(path,sourceid) values(?,?)", 
new Object[]{file.getAbsolutePath(), sourceid});
}

public void delete(File file){
SQLiteDatabase db = dbOpenHelper.getWritableDatabase();
db.execSQL("delete from uploadlog where path=?", new Object[]{file.getAbsolutePath()});
}
 }

四、多線程斷點下載

MainActivity.java

import java.io.File;
import cn.itcast.net.download.DownloadProgressListener;
import cn.itcast.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 MainActivity extends Activity {
    private EditText pathText;
    private TextView resultView;
    private Button downloadButton;
    private Button stopbutton;
    private ProgressBar progressBar;
    //hanlder的作用是用於往創建Hander對象所在的線程所綁定的消息隊列發送消息
    private Handler handler = new UIHander();
    
    private final class UIHander extends Handler{
public void handleMessage(Message msg) {
switch (msg.what) {
case 1:
int size = msg.getData().getInt("size");
progressBar.setProgress(size);
float num = (float)progressBar.getProgress() / (float)progressBar.getMax();
int result = (int)(num * 100);
resultView.setText(result+ "%");
if(progressBar.getProgress() == progressBar.getMax()){
Toast.makeText(getApplicationContext(), R.string.success, 1).show();
}
break;


case -1:
Toast.makeText(getApplicationContext(), R.string.error, 1).show();
break;
}
}
    }
    
    @Override
    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();
if(Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
File saveDir = Environment.getExternalStorageDirectory();
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;
}
}
/*
由於用戶的輸入事件(點擊button, 觸摸屏幕....)是由主線程負責處理的，如果主線程處於工作狀態，
此時用戶產生的輸入事件如果沒能在5秒內得到處理，系統就會報“應用無響應”錯誤。
所以在主線程裏不能執行一件比較耗時的工作，否則會因主線程阻塞而無法處理用戶的輸入事件，
導致“應用無響應”錯誤的出現。耗時的工作應該在子線程裏執行。
*/
private DownloadTask task;
/**
* 退出下載
*/
public void exit(){
if(task!=null) task.exit();
}
private void download(String path, File saveDir) {//運行在主線程
task = new DownloadTask(path, saveDir);
new Thread(task).start();
}


/*
* UI控件畫面的重繪(更新)是由主線程負責處理的，如果在子線程中更新UI控件的值，更新後的值不會重繪到屏幕上
* 一定要在主線程裏更新UI控件的值，這樣才能在屏幕上顯示出來，不能在子線程中更新UI控件的值
*/
private final class DownloadTask implements Runnable{
private String path;
private File saveDir;
private FileDownloader loader;
public DownloadTask(String path, File saveDir) {
this.path = path;
this.saveDir = saveDir;
}
/**
* 退出下載
*/
public void exit(){
if(loader!=null) loader.exit();
}

public void run() {
try {
loader = new FileDownloader(getApplicationContext(), path, saveDir, 3);
progressBar.setMax(loader.getFileSize());//設置進度條的最大刻度
loader.download(new DownloadProgressListener() {
public void onDownloadSize(int size) {
Message msg = new Message();
msg.what = 1;
msg.getData().putInt("size", size);
handler.sendMessage(msg);
}
});
} catch (Exception e) {
e.printStackTrace();
handler.sendMessage(handler.obtainMessage(-1));
}
}
}
    }
    
    
}

DBOpenHelper.java

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

public class DBOpenHelper extends SQLiteOpenHelper {
private static final String DBNAME = "itcast.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);
}
}

FileService.java

import java.util.HashMap;
import java.util.Map;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
/**
 * 業務bean
 *
 */
public class FileService {
private DBOpenHelper openHelper;


public FileService(Context context) {
openHelper = new DBOpenHelper(context);
}
/**
* 獲取每條線程已經下載的文件長度
* @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;
}
/**
* 保存每條線程已經下載的文件長度
* @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();
}
/**
* 實時更新每條線程已經下載的文件長度
* @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();
}
/**
* 當文件下載完成後，刪除對應的下載記錄
* @param path
*/
public void delete(String path){
SQLiteDatabase db = openHelper.getWritableDatabase();
db.execSQL("delete from filedownlog where downpath=?", new Object[]{path});
db.close();
}

}

DownloadProgressListener.java

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

DownloadThread.java

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;
/* 下載開始位置  */
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;//結束位置
http.setRequestProperty("Range", "bytes=" + startPos + "-"+ endPos);//設置獲取實體數據的範圍
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 (!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);
}
/**
* 下載是否完成
* @return
*/
public boolean isFinish() {
return finish;
}
/**
* 已經下載的內容大小
* @return 如果返回值爲-1,代表下載失敗
*/
public long getDownLength() {
return downLength;
}
}

FileDownloader.java

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 cn.itcast.service.FileService;


import android.content.Context;
import android.util.Log;
/**
 * 文件下載器
 * 
try {
FileDownloader loader = new FileDownloader(context, "http://browse.babasport.com/ejb3/ActivePort.exe",
new File("D:\\androidsoft\\test"), 2);
loader.getFileSize();//得到文件總大小
loader.download(new DownloadProgressListener(){
public void onDownloadSize(int size) {
print("已經下載："+ size);
}
});
} catch (Exception e) {
e.printStackTrace();
}
 */
public class FileDownloader {
private static final String TAG = "FileDownloader";
private Context context;
private FileService fileService;
/* 停止下載 */
private boolean exit;
/* 已下載文件長度 */
private int downloadSize = 0;
/* 原始文件長度 */
private int fileSize = 0;
/* 線程數 */
private DownloadThread[] threads;
/* 本地保存文件 */
private File saveFile;
/* 緩存各線程下載的長度*/
private Map<Integer, Integer> data = new ConcurrentHashMap<Integer, Integer>();
/* 每條線程下載的長度 */
private int block;
/* 下載路徑  */
private String downloadUrl;
/**
* 獲取線程數
*/
public int getThreadSize() {
return threads.length;
}
/**
* 退出下載
*/
public void exit(){
this.exit = true;
}
public boolean getExit(){
return this.exit;
}
/**
* 獲取文件大小
* @return
*/
public int getFileSize() {
return fileSize;
}
/**
* 累計已下載大小
* @param size
*/
protected synchronized void append(int size) {
downloadSize += size;
}
/**
* 更新指定線程最後下載的位置
* @param threadId 線程id
* @param pos 最後下載的位置
*/
protected synchronized void update(int threadId, int pos) {
this.data.put(threadId, pos);
this.fileService.update(this.downloadUrl, threadId, pos);
}
/**
* 構建文件下載器
* @param downloadUrl 下載路徑
* @param fileSaveDir 文件保存目錄
* @param threadNum 下載線程數
*/
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();//根據響應獲取文件大小
if (this.fileSize <= 0) throw new RuntimeException("Unkown file size ");

String filename = getFileName(conn);//獲取文件名稱
this.saveFile = new File(fileSaveDir, filename);//構建保存文件
Map<Integer, Integer> logdata = fileService.getData(downloadUrl);//獲取下載記錄
if(logdata.size()>0){//如果存在下載記錄
for(Map.Entry<Integer, Integer> entry : logdata.entrySet())
data.put(entry.getKey(), entry.getValue());//把各條線程已經下載的數據長度放入data中
}
if(this.data.size()==this.threads.length){//下面計算所有線程已經下載的數據總長度
for (int i = 0; i < this.threads.length; i++) {
this.downloadSize += this.data.get(i+1);
}
print("已經下載的長度"+ this.downloadSize);
}
//計算每條線程下載的數據長度
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");
}
}
/**
* 獲取文件名
*/
private String getFileName(HttpURLConnection conn) {
String filename = this.downloadUrl.substring(this.downloadUrl.lastIndexOf('/') + 1);
if(filename==null || "".equals(filename.trim())){//如果獲取不到文件名稱
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";//默認取一個文件名
}
return filename;
}

/**
*  開始下載文件
* @param listener 監聽下載數量的變化,如果不需要了解實時下載的數量,可以設置爲null
* @return 已下載文件大小
* @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){//如果原先未曾下載或者原先的下載線程數與現在的線程數不一致
this.data.clear();
for (int i = 0; i < this.threads.length; i++) {
this.data.put(i+1, 0);//初始化每條線程已經下載的數據長度爲0
}
this.downloadSize = 0;
}
for (int i = 0; i < this.threads.length; i++) {//開啓線程進行下載
int downLength = this.data.get(i+1);
if(downLength < this.block && this.downloadSize<this.fileSize){//判斷線程是否已經完成下載,否則繼續下載
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);//如果存在下載記錄，刪除它們，然後重新添加
fileService.save(this.downloadUrl, this.data);
boolean notFinish = true;//下載未完成
while (notFinish) {// 循環判斷所有線程是否完成下載
Thread.sleep(900);
notFinish = false;//假定全部線程下載完成
for (int i = 0; i < this.threads.length; i++){
if (this.threads[i] != null && !this.threads[i].isFinish()) {//如果發現線程未完成下載
notFinish = true;//設置標誌爲下載沒有完成
if(this.threads[i].getDownLength() == -1){//如果下載失敗,再重新下載
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);//通知目前已經下載完成的數據長度
}
if(downloadSize == this.fileSize) fileService.delete(this.downloadUrl);//下載完成刪除記錄
} catch (Exception e) {
print(e.toString());
throw new Exception("file download error");
}
return this.downloadSize;
}
/**
* 獲取Http響應頭字段
* @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頭字段
* @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);
}
}