android学习笔记---31_多线程断点下载器,下载原理实现
1.1.31_多线程断点下载器
-----------------------
1.软件界面:
文件下载路径
text框
button 下载
点击后,下面显示下载进度
-----------------------------------
2.进度条(ProgressBar)
在布局xml文件中添加进度条代码：
<ProgressBar
android:layout_width="fill_parent"
android:layout_height="20px"
style="?android:attr/progressBarStyleHorizontal"//问号代表引用.这个属性值.,这里
指定了//水平进度条
android:id="@+id/downloadbar"/>
在代码中操作进度条：
ProgressBar.setMax(100);//设置最大刻度
ProgressBar.setProgress(0);//设置进度条的当前刻度，如果进度条的最大刻度为100，当前刻
度为50，进度条将进行到一半。
------------------------------------------------
2012-04-03
----------------
1.下面是断点下载器的所有代码:MulThreadDownloader
------------------------------------
a.新建android项目:MulThreadDownloader
b./MulThreadDownloader/src/com/credream/multhreaddownloader/MulThreadDownloaderActiv
ity.java
package com.credream.multhreaddownloader;
import java.io.File;
import com.credream.net.download.DownloadProgressListener;
import com.credream.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.webkit.DownloadListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.Toast;
import android.widget.SimpleAdapter.ViewBinder;
import android.widget.TextView;
public class MulThreadDownloaderActivity extends Activity
{
private EditText pathText;
private TextView resultView;
private Button button;
private Button stopbutton;
private ProgressBar progressBar;
// 解决主线程重绘屏幕
private Handler handler = new UIHander();
// 这个变量被主线程创建.实现线程之间的通信
// handler的作用是用于往创建Hander对象所在的线程所绑定的消息队列发送消息
private final class UIHander extends Handler
{
@Override
public void handleMessage(Message msg)
{
switch (msg.what)
{
case 1:
int size = msg.getData().getInt("size");
progressBar.setProgress(size);
// 30 / 100 =0.33333
float num = (float) progressBar.getProgress()
/ (float) progressBar.getMax();
// 0.33333
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);
button = (Button) this.findViewById(R.id.button);
progressBar = (ProgressBar) this.findViewById(R.id.progressBar);
stopbutton = (Button) this.findViewById(R.id.stopbutton);
ButtonClickListener listener = new ButtonClickListener();
// button.setOnClickListener(new ButtonClickListener());
button.setOnClickListener(listener);
stopbutton.setOnClickListener(listener);
}
// 内部类
private final class ButtonClickListener implements View.OnClickListener
{
public void onClick(View v)
{
/*
* 这种做法也可以,因为当界面显示的时候,会创建这两个对象,用户点击按钮的时候 传过来的
是各自的不同的对象
* if(v==button){
*
* }else if(v==stopbutton){
*
* }
*/
switch (v.getId())
{
case R.id.button:
String path = pathText.getText().toString();
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED))
{
// 为上面这个状态的时候表示可以写入数据
File saveDir = Environment.getExternalStorageDirectory();
// 得到sd卡的根目录
// 开始下载文件
download(path, saveDir);
// 调用这个方法的时候会执行下面的方法,下面的download方法仅仅开启了一个线程所以不会出
现,主线程长时间等待的问题
} else
{
Toast.makeText(getApplicationContext(),
R.string.sdcarderror,1).show();
}
button.setEnabled(false);
stopbutton.setEnabled(true);
break;
case R.id.stopbutton:
exit();
button.setEnabled(true);
stopbutton.setEnabled(false);
break;
// 最好用服务来做,这样也就是说,可以一边使用其他软件,一边进行下载东西
// 下载的代码不要写到activity中,要写到服务代码中
}
}
/**
*
由于用户的输入事件(点击button, 触摸屏幕....)是由主线程负责处理的，如果主线程处于工
作状态，
* 此时用户产生的输入事件如果没能在5秒内得到处理，系统就会报“应用无响应”错误。
* 所以在主线程里不能执行一件比较耗时的工作，否则会因主线程阻塞而无法处理用户的输入
事件，
* 导致“应用无响应”错误的出现。耗时的工作应该在子线程里执行。
*
* @param path
* @param saveDir
*/
private DownloadTask task;
public void exit()
{
if (task != null)
{
task.exit();
}
}
private void download(String path, File saveDir)
// 因为这个api是
// 运行在主线程的
//由于方法要运行很长时间,会导致主线程一直在工作状态.
{
task = new DownloadTask(path, saveDir);
new Thread(task).start();
// 在先前的类中加入断点保存功能
try
{
// FileDownloader loader = new
// FileDownloader(getApplicationContext(),path,saveDir, 3);
// 未解决主线程问题,需要把这个转移到子线程中实现
// 这里在new这个对象的时候,会现在数据库中得到先前的下载记录
// 下载路径,文件的保存目录以及线程数,这时候把查询的数据放到data中.
// loader.getFileSize();//得到文件总大小
// loader.download(new DownloadProgressListener(){
// 调用download方法就可以实现文件的下载了,匿名内部类用来得到目前该文件下载的数据量,
这个类
// 会不断的被调用来提示下载量.
// loader.download(null);
// 未解决主线程问题,需要把这个转移到子线程中实现
// 得到下载的进度
// 如果文件有100m,那么下载会很长时间
} catch (Exception e)
{
e.printStackTrace();
}
}
}
/**
* UI控件的画面的重新绘制,是有主线程负责处理的,如果在子线程中更新UI控件的值,
更新后的值,不会重绘到屏幕上
*/
private final class DownloadTask implements Runnable
{
private String path;
private File saveDir;
FileDownloader loader;
public DownloadTask(String path, File saveDir)
{
this.path = path;
this.saveDir = saveDir;
}
/**
* 退出下载
*/
public void exit()
{
if (loader != null)
{
loader.exit();
}
}
@Override
public void run()
{
try
{
loader = new FileDownloader(getApplicationContext(), path,
saveDir, 3);
progressBar.setMax(loader.getFileSize());
// 设置进度条的最大刻度
loader.download(new DownloadProgressListener()
// 用匿名内部类来获取下载的长度
{
// 下载中会不断调用这个方法,下载的数据量会传入
@Override
public void onDownloadSize(int size)
{
Message msg = new Message();
msg.what = 1;// 为了区分不同的消息,给消息定义的id
msg.getData().putInt("size", size);
// getData对象相当于一个map
/**
* ----------------------------------------
主线程 1. 消息队列:
* 2. 发来一条消息
消息处理器: 在没有消息的时候,消息处理系统处于等待状态,当
* 收到消息的时候,消息处理系统就会被唤醒,然后会 首先在消息队列中取得消息,取
得消息后 Message
* msg=getMessage() 访问消息对象中的一个成员变量 Handler handler=msg.
* target 然后handler.handleMessage(msg) 这一段代码是运行在主线程中的
* ----------------------------------------
*/
handler.sendMessage(msg);
// 把消息队列发送给主线程
// 因为在android源码中,sendMessage,里处理的时候
// msg.target=this用于把当前的handler赋值给了msg,的target
// 也就是把Message类的target变量赋值了handler
// progressBar.setProgress(size);//设置进度条的当前刻度
// 计算百分率
/*
* //30 / 100 =0.33333 float num=(float)
* progressBar.getProgress()/(float)
* progressBar.getMax(); //0.33333 int
* result=(int)(num*100);
* resultView.setText(result+"%");
*/
// 还有一个错误,这里更新它的值,更新后的值,不会重绘到屏幕上
}
});
// 100m,导致主线程一直在工作状态
} catch (Exception e)
{
// 通过发送消息给消息处理器进行处理
e.printStackTrace();
handler.sendMessage(handler.obtainMessage(-1));
// 发送消息,-1是消息的id
}
}
}
}
----------------------------------
2./MulThreadDownloader/src/com/credream/net/download/DownloadProgressListener.java
package com.credream.net.download;
public interface DownloadProgressListener {
//接口,要想得到当前已经下载的长度,要实现这个接口
public void onDownloadSize(int size);
}
----------------------
d./MulThreadDownloader/src/com/credream/net/download/DownloadThread.java
package com.credream.net.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;
public class DownloadThread extends Thread {
private static final String TAG = "DownloadThread";
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 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 (!downloader.getExit() && (offset =
inStream.read(buffer, 0, 1024)) != -1) {
threadfile.write(buffer, 0, offset);
downLength += offset;
downloader.update(this.threadId,
downLength);
//调用update,给他线程id和下载的数据量.
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;
}
}
--------------------
e./MulThreadDownloader/src/com/credream/net/download/FileDownloader.java
package com.credream.net.download;
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 com.credream.service.FileService;
import android.content.Context;
import android.util.Log;
/**
* 文件下载器
*
try {
FileDownloader loader = new FileDownloader(context,
"http://browse.babasport.com/ejb3/ActivePort.exe",
new File("D:\\androidsoft\\test"), 2);
//这里在new这个对象的时候,会现在数据库中得到先前的下
载记录
//下载路径,文件的保存目录以及线程数,这时候把查询的
数据放到data中.
loader.getFileSize();//得到文件总大小
loader.download(new DownloadProgressListener(){
//调用download方法就可以实现文件的下载了,匿名内部类用来得到目前该文
件下载的数据量,这个类
//会不断的被调用来提示下载量.
public void onDownloadSize(int size) {
print("已经下载："+ size);
}
});
} catch (Exception e) {
e.printStackTrace();
}
*/
//多线程断点下载的实现类,多了断点功能
public class FileDownloader {
private static final String TAG = "FileDownloader";
private Context context;
private FileService fileService;
/* 停止下载 */
private boolean exit;
/* 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 DownloadThread[] threads;
/* 本地保存文件 */
private File saveFile;
/* 缓存各线程下载的长度*/
private Map<Integer, Integer> data = new ConcurrentHashMap<Integer,
Integer>();
/* 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;
}
/**
* 退出下载
*/
public void exit(){
this.exit = true;
}
public boolean getExit(){
return this.exit;
}
/**
* 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 synchronized void update(int threadId, int pos) {
this.data.put(threadId, pos);
this.fileService.update(this.downloadUrl, threadId, pos);
//根据传的值,不停的更新下载的数据量
}
/**
* 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 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();//根据响应获
取文件大小
if (this.fileSize <= 0) throw new RuntimeException
("Unkown file size ");
String filename = getFileName(conn);//获取文件名称
this.saveFile = new File(fileSaveDir, filename);//构
建保存文件
Map<Integer, Integer> logdata = fileService.getData
(downloadUrl);//获取下载记录
if(logdata.size()>0){//如果存在下载记录
for(Map.Entry<Integer, Integer> entry :
logdata.entrySet())
data.put(entry.getKey(),
entry.getValue());//把各条线程已经下载的数据长度放入data中
}
if(this.data.size()==this.threads.length){//下面计算
所有线程已经下载的数据总长度
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);
}
//计算每条线程下载的数据长度
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");
}
}
/**
* 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(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
载或者原先的下载线程数与现在的线程数不一致
this.data.clear();//清除后进行初始化设置
for (int i = 0; i < this.threads.length; i++) {
this.data.put(i+1, 0);//初始化每条线程已经下
载的数据长度为0
}
this.downloadSize = 0;
}
for (int i = 0; i < this.threads.length; i++) {//开启线程进
行下载
int downLength = this.data.get(i+1);
if(downLength < this.block &&
this.downloadSize<this.fileSize){//判断线程是否已经完成下载,否则继续下载
//原先的下载量和已下载的比较
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);//如果存在下载记录，删
除它们，然后重新添加
fileService.save(this.downloadUrl, this.data);
boolean notFinish = true;//下载未完成
while (notFinish) {// 循环判断所有线程是否完成下载,只要没有
下载完成就会一直调用这个
Thread.sleep(900);
notFinish = false;//假定全部线程下载完成
for (int i = 0; i < this.threads.length; i++){//判断
所有的线程是否下载完成
if (this.threads[i] != null && !
this.threads[i].isFinish()) {//如果发现线程未完成下载
notFinish = true;//设置标志为下载没
有完成
if(this.threads[i].getDownLength()
== -1){//如果下载失败,再重新下载
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);//通知目前已经下载完成的数据长度
}
if(downloadSize == this.fileSize) fileService.delete
(this.downloadUrl);//下载完成删除记录
//判断下载的size和文件size是否一致
} catch (Exception e) {
print(e.toString());
throw new Exception("file download error");
}
return this.downloadSize;
}
/**
* 获取Http响应头字段
* @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头字段
* @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);
}
}
------------------------------------------
f./MulThreadDownloader/src/com/credream/service/DBOpenHelper.java
package com.credream.service;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
//用于创建数据库和数据库表,
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) {
//创建的表用于创建断点.sql
//创建数据库以及创建数据库表
db.execSQL("CREATE TABLE IF NOT EXISTS filedownlog (id integer primary key autoincrement, downpath varchar(100), threadid INTEGER, downlength INTEGER)");
//CREATE TABLE IF NOT EXISTS filedownlog (id integer primary key autoincrement//表id自增长
//, downpath varchar(100)//文件路径, threadid INTEGER//线程id,
//downlength INTEGER) //下载长度
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS filedownlog");
onCreate(db);
}
}
--------------------------------------
g./MulThreadDownloader/src/com/credream/service/FileService.java
package com.credream.service;
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<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;
}
/**
* 保存每条线程已经下载的文件长度
* @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();
}
/**
* 实时更新每条线程已经下载的文件长度
* 调用的频率是很高的,可能几毫秒就会更新一次
* @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();
}
/**
* 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 filedownlog where downpath=?", new Object[]{path});
db.close();
}
}
----------------------------
h./MulThreadDownloader/res/layout/main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/path" />
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="http://192.168.0.110:6118/MobileAddressQueryTest/shopping.rar"
android:id="@+id/path"
/>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button"
android:id="@+id/button"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/stopbutton"
android:enabled="false"
android:id="@+id/stopbutton"
/>
</LinearLayout>
<!--
下面是进度条,有两种一种是环形进度条,另一种是水平进度条,
环形进度条,是一种没有刻度的,也叫做不确定性进度条 -->
<ProgressBar
android:layout_width="fill_parent"
android:layout_height="18dp"
style="?android:attr/progressBarStyleHorizontal"
android:id="@+id/progressBar"
/>
<!--style="" 样式,水平进度条的样式,由android系统提供的 -->
<!-- 用来显示进度条的百分比 -->
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:id="@+id/resultView" />
</LinearLayout>
-----------------------------------------
i./MulThreadDownloader/res/values/strings.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, MulThreadDownloaderActivity!</string>
<string name="app_name">多线程下载器</string>
<string name="path">下载路径</string>
<string name="button">下载</string>
<string name="success">下载完成</string>
<string name="error">下载失败</string>
<string name="sdcarderror">SDCard不存在或者写保护</string>
<string name="stopbutton">停止下载</string>
</resources>
----------------------------------
j./MulThreadDownloader/AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.credream.multhreaddownloader"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:label="@string/app_name"
android:name=".MulThreadDownloaderActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<!--访问网络权限-->
<uses-permission android:name="android.permission.INTERNET"/>
<!-- 在SDCard中创建与删除文件权限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<!-- 往SDCard写入数据权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
</manifest>
-------------------------------------------
-----------------------
1.软件界面:
文件下载路径
text框
button 下载
点击后,下面显示下载进度
-----------------------------------
2.进度条(ProgressBar)
在布局xml文件中添加进度条代码：
<ProgressBar
android:layout_width="fill_parent"
android:layout_height="20px"
style="?android:attr/progressBarStyleHorizontal"//问号代表引用.这个属性值.,这里
指定了//水平进度条
android:id="@+id/downloadbar"/>
在代码中操作进度条：
ProgressBar.setMax(100);//设置最大刻度
ProgressBar.setProgress(0);//设置进度条的当前刻度，如果进度条的最大刻度为100，当前刻
度为50，进度条将进行到一半。
------------------------------------------------
2012-04-03
----------------
1.下面是断点下载器的所有代码:MulThreadDownloader
------------------------------------
a.新建android项目:MulThreadDownloader
b./MulThreadDownloader/src/com/credream/multhreaddownloader/MulThreadDownloaderActiv
ity.java
package com.credream.multhreaddownloader;
import java.io.File;
import com.credream.net.download.DownloadProgressListener;
import com.credream.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.webkit.DownloadListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ProgressBar;
import android.widget.Toast;
import android.widget.SimpleAdapter.ViewBinder;
import android.widget.TextView;
public class MulThreadDownloaderActivity extends Activity
{
private EditText pathText;
private TextView resultView;
private Button button;
private Button stopbutton;
private ProgressBar progressBar;
// 解决主线程重绘屏幕
private Handler handler = new UIHander();
// 这个变量被主线程创建.实现线程之间的通信
// handler的作用是用于往创建Hander对象所在的线程所绑定的消息队列发送消息
private final class UIHander extends Handler
{
@Override
public void handleMessage(Message msg)
{
switch (msg.what)
{
case 1:
int size = msg.getData().getInt("size");
progressBar.setProgress(size);
// 30 / 100 =0.33333
float num = (float) progressBar.getProgress()
/ (float) progressBar.getMax();
// 0.33333
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);
button = (Button) this.findViewById(R.id.button);
progressBar = (ProgressBar) this.findViewById(R.id.progressBar);
stopbutton = (Button) this.findViewById(R.id.stopbutton);
ButtonClickListener listener = new ButtonClickListener();
// button.setOnClickListener(new ButtonClickListener());
button.setOnClickListener(listener);
stopbutton.setOnClickListener(listener);
}
// 内部类
private final class ButtonClickListener implements View.OnClickListener
{
public void onClick(View v)
{
/*
* 这种做法也可以,因为当界面显示的时候,会创建这两个对象,用户点击按钮的时候 传过来的
是各自的不同的对象
* if(v==button){
*
* }else if(v==stopbutton){
*
* }
*/
switch (v.getId())
{
case R.id.button:
String path = pathText.getText().toString();
if (Environment.getExternalStorageState().equals(
Environment.MEDIA_MOUNTED))
{
// 为上面这个状态的时候表示可以写入数据
File saveDir = Environment.getExternalStorageDirectory();
// 得到sd卡的根目录
// 开始下载文件
download(path, saveDir);
// 调用这个方法的时候会执行下面的方法,下面的download方法仅仅开启了一个线程所以不会出
现,主线程长时间等待的问题
} else
{
Toast.makeText(getApplicationContext(),
R.string.sdcarderror,1).show();
}
button.setEnabled(false);
stopbutton.setEnabled(true);
break;
case R.id.stopbutton:
exit();
button.setEnabled(true);
stopbutton.setEnabled(false);
break;
// 最好用服务来做,这样也就是说,可以一边使用其他软件,一边进行下载东西
// 下载的代码不要写到activity中,要写到服务代码中
}
}
/**
*
由于用户的输入事件(点击button, 触摸屏幕....)是由主线程负责处理的，如果主线程处于工
作状态，
* 此时用户产生的输入事件如果没能在5秒内得到处理，系统就会报“应用无响应”错误。
* 所以在主线程里不能执行一件比较耗时的工作，否则会因主线程阻塞而无法处理用户的输入
事件，
* 导致“应用无响应”错误的出现。耗时的工作应该在子线程里执行。
*
* @param path
* @param saveDir
*/
private DownloadTask task;
public void exit()
{
if (task != null)
{
task.exit();
}
}
private void download(String path, File saveDir)
// 因为这个api是
// 运行在主线程的
//由于方法要运行很长时间,会导致主线程一直在工作状态.
{
task = new DownloadTask(path, saveDir);
new Thread(task).start();
// 在先前的类中加入断点保存功能
try
{
// FileDownloader loader = new
// FileDownloader(getApplicationContext(),path,saveDir, 3);
// 未解决主线程问题,需要把这个转移到子线程中实现
// 这里在new这个对象的时候,会现在数据库中得到先前的下载记录
// 下载路径,文件的保存目录以及线程数,这时候把查询的数据放到data中.
// loader.getFileSize();//得到文件总大小
// loader.download(new DownloadProgressListener(){
// 调用download方法就可以实现文件的下载了,匿名内部类用来得到目前该文件下载的数据量,
这个类
// 会不断的被调用来提示下载量.
// loader.download(null);
// 未解决主线程问题,需要把这个转移到子线程中实现
// 得到下载的进度
// 如果文件有100m,那么下载会很长时间
} catch (Exception e)
{
e.printStackTrace();
}
}
}
/**
* UI控件的画面的重新绘制,是有主线程负责处理的,如果在子线程中更新UI控件的值,
更新后的值,不会重绘到屏幕上
*/
private final class DownloadTask implements Runnable
{
private String path;
private File saveDir;
FileDownloader loader;
public DownloadTask(String path, File saveDir)
{
this.path = path;
this.saveDir = saveDir;
}
/**
* 退出下载
*/
public void exit()
{
if (loader != null)
{
loader.exit();
}
}
@Override
public void run()
{
try
{
loader = new FileDownloader(getApplicationContext(), path,
saveDir, 3);
progressBar.setMax(loader.getFileSize());
// 设置进度条的最大刻度
loader.download(new DownloadProgressListener()
// 用匿名内部类来获取下载的长度
{
// 下载中会不断调用这个方法,下载的数据量会传入
@Override
public void onDownloadSize(int size)
{
Message msg = new Message();
msg.what = 1;// 为了区分不同的消息,给消息定义的id
msg.getData().putInt("size", size);
// getData对象相当于一个map
/**
* ----------------------------------------
主线程 1. 消息队列:
* 2. 发来一条消息
消息处理器: 在没有消息的时候,消息处理系统处于等待状态,当
* 收到消息的时候,消息处理系统就会被唤醒,然后会 首先在消息队列中取得消息,取
得消息后 Message
* msg=getMessage() 访问消息对象中的一个成员变量 Handler handler=msg.
* target 然后handler.handleMessage(msg) 这一段代码是运行在主线程中的
* ----------------------------------------
*/
handler.sendMessage(msg);
// 把消息队列发送给主线程
// 因为在android源码中,sendMessage,里处理的时候
// msg.target=this用于把当前的handler赋值给了msg,的target
// 也就是把Message类的target变量赋值了handler
// progressBar.setProgress(size);//设置进度条的当前刻度
// 计算百分率
/*
* //30 / 100 =0.33333 float num=(float)
* progressBar.getProgress()/(float)
* progressBar.getMax(); //0.33333 int
* result=(int)(num*100);
* resultView.setText(result+"%");
*/
// 还有一个错误,这里更新它的值,更新后的值,不会重绘到屏幕上
}
});
// 100m,导致主线程一直在工作状态
} catch (Exception e)
{
// 通过发送消息给消息处理器进行处理
e.printStackTrace();
handler.sendMessage(handler.obtainMessage(-1));
// 发送消息,-1是消息的id
}
}
}
}
----------------------------------
2./MulThreadDownloader/src/com/credream/net/download/DownloadProgressListener.java
package com.credream.net.download;
public interface DownloadProgressListener {
//接口,要想得到当前已经下载的长度,要实现这个接口
public void onDownloadSize(int size);
}
----------------------
d./MulThreadDownloader/src/com/credream/net/download/DownloadThread.java
package com.credream.net.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;
public class DownloadThread extends Thread {
private static final String TAG = "DownloadThread";
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 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 (!downloader.getExit() && (offset =
inStream.read(buffer, 0, 1024)) != -1) {
threadfile.write(buffer, 0, offset);
downLength += offset;
downloader.update(this.threadId,
downLength);
//调用update,给他线程id和下载的数据量.
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;
}
}
--------------------
e./MulThreadDownloader/src/com/credream/net/download/FileDownloader.java
package com.credream.net.download;
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 com.credream.service.FileService;
import android.content.Context;
import android.util.Log;
/**
* 文件下载器
*
try {
FileDownloader loader = new FileDownloader(context,
"http://browse.babasport.com/ejb3/ActivePort.exe",
new File("D:\\androidsoft\\test"), 2);
//这里在new这个对象的时候,会现在数据库中得到先前的下
载记录
//下载路径,文件的保存目录以及线程数,这时候把查询的
数据放到data中.
loader.getFileSize();//得到文件总大小
loader.download(new DownloadProgressListener(){
//调用download方法就可以实现文件的下载了,匿名内部类用来得到目前该文
件下载的数据量,这个类
//会不断的被调用来提示下载量.
public void onDownloadSize(int size) {
print("已经下载："+ size);
}
});
} catch (Exception e) {
e.printStackTrace();
}
*/
//多线程断点下载的实现类,多了断点功能
public class FileDownloader {
private static final String TAG = "FileDownloader";
private Context context;
private FileService fileService;
/* 停止下载 */
private boolean exit;
/* 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 DownloadThread[] threads;
/* 本地保存文件 */
private File saveFile;
/* 缓存各线程下载的长度*/
private Map<Integer, Integer> data = new ConcurrentHashMap<Integer,
Integer>();
/* 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;
}
/**
* 退出下载
*/
public void exit(){
this.exit = true;
}
public boolean getExit(){
return this.exit;
}
/**
* 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 synchronized void update(int threadId, int pos) {
this.data.put(threadId, pos);
this.fileService.update(this.downloadUrl, threadId, pos);
//根据传的值,不停的更新下载的数据量
}
/**
* 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 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();//根据响应获
取文件大小
if (this.fileSize <= 0) throw new RuntimeException
("Unkown file size ");
String filename = getFileName(conn);//获取文件名称
this.saveFile = new File(fileSaveDir, filename);//构
建保存文件
Map<Integer, Integer> logdata = fileService.getData
(downloadUrl);//获取下载记录
if(logdata.size()>0){//如果存在下载记录
for(Map.Entry<Integer, Integer> entry :
logdata.entrySet())
data.put(entry.getKey(),
entry.getValue());//把各条线程已经下载的数据长度放入data中
}
if(this.data.size()==this.threads.length){//下面计算
所有线程已经下载的数据总长度
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);
}
//计算每条线程下载的数据长度
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");
}
}
/**
* 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(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
载或者原先的下载线程数与现在的线程数不一致
this.data.clear();//清除后进行初始化设置
for (int i = 0; i < this.threads.length; i++) {
this.data.put(i+1, 0);//初始化每条线程已经下
载的数据长度为0
}
this.downloadSize = 0;
}
for (int i = 0; i < this.threads.length; i++) {//开启线程进
行下载
int downLength = this.data.get(i+1);
if(downLength < this.block &&
this.downloadSize<this.fileSize){//判断线程是否已经完成下载,否则继续下载
//原先的下载量和已下载的比较
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);//如果存在下载记录，删
除它们，然后重新添加
fileService.save(this.downloadUrl, this.data);
boolean notFinish = true;//下载未完成
while (notFinish) {// 循环判断所有线程是否完成下载,只要没有
下载完成就会一直调用这个
Thread.sleep(900);
notFinish = false;//假定全部线程下载完成
for (int i = 0; i < this.threads.length; i++){//判断
所有的线程是否下载完成
if (this.threads[i] != null && !
this.threads[i].isFinish()) {//如果发现线程未完成下载
notFinish = true;//设置标志为下载没
有完成
if(this.threads[i].getDownLength()
== -1){//如果下载失败,再重新下载
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);//通知目前已经下载完成的数据长度
}
if(downloadSize == this.fileSize) fileService.delete
(this.downloadUrl);//下载完成删除记录
//判断下载的size和文件size是否一致
} catch (Exception e) {
print(e.toString());
throw new Exception("file download error");
}
return this.downloadSize;
}
/**
* 获取Http响应头字段
* @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头字段
* @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);
}
}
------------------------------------------
f./MulThreadDownloader/src/com/credream/service/DBOpenHelper.java
package com.credream.service;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
//用于创建数据库和数据库表,
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) {
//创建的表用于创建断点.sql
//创建数据库以及创建数据库表
db.execSQL("CREATE TABLE IF NOT EXISTS filedownlog (id integer primary key autoincrement, downpath varchar(100), threadid INTEGER, downlength INTEGER)");
//CREATE TABLE IF NOT EXISTS filedownlog (id integer primary key autoincrement//表id自增长
//, downpath varchar(100)//文件路径, threadid INTEGER//线程id,
//downlength INTEGER) //下载长度
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS filedownlog");
onCreate(db);
}
}
--------------------------------------
g./MulThreadDownloader/src/com/credream/service/FileService.java
package com.credream.service;
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<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;
}
/**
* 保存每条线程已经下载的文件长度
* @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();
}
/**
* 实时更新每条线程已经下载的文件长度
* 调用的频率是很高的,可能几毫秒就会更新一次
* @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();
}
/**
* 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 filedownlog where downpath=?", new Object[]{path});
db.close();
}
}
----------------------------
h./MulThreadDownloader/res/layout/main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/path" />
<EditText
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="http://192.168.0.110:6118/MobileAddressQueryTest/shopping.rar"
android:id="@+id/path"
/>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/button"
android:id="@+id/button"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/stopbutton"
android:enabled="false"
android:id="@+id/stopbutton"
/>
</LinearLayout>
<!--
下面是进度条,有两种一种是环形进度条,另一种是水平进度条,
环形进度条,是一种没有刻度的,也叫做不确定性进度条 -->
<ProgressBar
android:layout_width="fill_parent"
android:layout_height="18dp"
style="?android:attr/progressBarStyleHorizontal"
android:id="@+id/progressBar"
/>
<!--style="" 样式,水平进度条的样式,由android系统提供的 -->
<!-- 用来显示进度条的百分比 -->
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:id="@+id/resultView" />
</LinearLayout>
-----------------------------------------
i./MulThreadDownloader/res/values/strings.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="hello">Hello World, MulThreadDownloaderActivity!</string>
<string name="app_name">多线程下载器</string>
<string name="path">下载路径</string>
<string name="button">下载</string>
<string name="success">下载完成</string>
<string name="error">下载失败</string>
<string name="sdcarderror">SDCard不存在或者写保护</string>
<string name="stopbutton">停止下载</string>
</resources>
----------------------------------
j./MulThreadDownloader/AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.credream.multhreaddownloader"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk android:minSdkVersion="8" />
<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<activity
android:label="@string/app_name"
android:name=".MulThreadDownloaderActivity" >
<intent-filter >
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<!--访问网络权限-->
<uses-permission android:name="android.permission.INTERNET"/>
<!-- 在SDCard中创建与删除文件权限 -->
<uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
<!-- 往SDCard写入数据权限 -->
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
</manifest>----------------------------------------------------------------------
3.测试:
a.测试的时候,先打开tomcat,并且在根目录下方一个文件shopping.rar
b.然后打开android的应用,点击下载,下载一半的时候,点击停止下载
c.这时候,当再次点击下载的时候,会接着原来的部分进行文件的下载
----------------------------
d.等下载完成后,把文件从文件浏览器中导出出来然后,打开测试有没有损坏
e.注意打开的时候要先把文件拷贝一份到其他的盘里面,因为刚刚导出的文件如果
直接打开的话会报,这个文件正在被eclipse使用的错误.
-------------------------------------------
