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package com.changcheng.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.changcheng.download.service.FileService;
import android.content.Context;
import android.util.Log;
/**
* 文件下载器
* @author lihuoming@sohu.com
*
*/
public class FileDownloader {
private Context context;
private FileService fileService;
private static final String TAG = "FileDownloader";
/* 已下载文件大小 */
private int downloadSize = 0;
/* 原始文件大小 */
private int fileSize = 0;
/* 线程数 */
private DownloadThread[] threads;
/* 下载路径 */
private URL url;
/* 本地保存文件 */
private File saveFile;
/* 下载记录文件 */
private File logFile;
/* 缓存各线程最后下载的位置*/
private Map<Integer, Integer> data = new ConcurrentHashMap<Integer, Integer>();
/* 每条线程下载的大小 */
private int block;
private String downloadUrl;//下载路径
/**
* 获取线程数
*/
public int getThreadSize() {
return threads.length;
}
/**
* 获取文件大小
* @return
*/
public int getFileSize() {
return fileSize;
}
/**
* 累计已下载大小
* @param size
*/
protected synchronized void append(int size) {
downloadSize += size;
}
/**
* 更新指定线程最后下载的位置
* @param threadId 线程id
* @param pos 最后下载的位置
*/
protected void update(int threadId, int pos) {
this.data.put(threadId, pos);
}
/**
* 保存记录文件
*/
protected synchronized void saveLogFile() {
this.fileService.update(this.downloadUrl, this.data);
}
/**
* 构建文件下载器
* @param downloadUrl 下载路径
* @param fileSaveDir 文件保存目录
* @param threadNum 下载线程数
*/
public FileDownloader(Context context, String downloadUrl, File fileSaveDir, int threadNum) {
try {
this.context = context;
this.downloadUrl = downloadUrl;
fileService = new FileService(context);
this.url = new URL(downloadUrl);
if(!fileSaveDir.exists()) fileSaveDir.mkdirs();
this.threads = new DownloadThread[threadNum];
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(6*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("无法获知文件大小 ");
String filename = getFileName(conn);
this.saveFile = new File(fileSaveDir, filename);/* 保存文件 */
Map<Integer, Integer> logdata = fileService.getData(downloadUrl);
if(logdata.size()>0){
data.putAll(logdata);
}
this.block = this.fileSize / this.threads.length + 1;
if(this.data.size()==this.threads.length){
for (int i = 0; i < this.threads.length; i++) {
this.downloadSize += this.data.get(i+1)-(this.block * i);
}
print("已经下载的长度"+ this.downloadSize);
}
}else{
throw new RuntimeException("服务器响应错误 ");
}
} catch (Exception e) {
print(e.toString());
throw new RuntimeException("连接不到下载路径 ");
}
}
/**
* 获取文件名
*/
private String getFileName(HttpURLConnection conn) {
String filename = this.url.toString().substring(this.url.toString().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 {
if(this.data.size() != this.threads.length){
this.data.clear();
for (int i = 0; i < this.threads.length; i++) {
this.data.put(i+1, this.block * i);
}
}
for (int i = 0; i < this.threads.length; i++) {
int downLength = this.data.get(i+1) - (this.block * i);
if(downLength < this.block && this.data.get(i+1)<this.fileSize){ //该线程未完成下载时,继续下载
RandomAccessFile randOut = new RandomAccessFile(this.saveFile, "rw");
if(this.fileSize>0) randOut.setLength(this.fileSize);
randOut.seek(this.data.get(i+1));
this.threads[i] = new DownloadThread(this, this.url, randOut, this.block, this.data.get(i+1), i+1);
this.threads[i].setPriority(7);
this.threads[i].start();
}else{
this.threads[i] = null;
}
}
this.fileService.save(this.downloadUrl, this.data);
boolean notFinish = true;//下载未完成
while (notFinish) {// 循环判断是否下载完毕
Thread.sleep(900);
notFinish = false;//假定下载完成
for (int i = 0; i < this.threads.length; i++){
if (this.threads[i] != null && !this.threads[i].isFinish()) {
notFinish = true;//下载没有完成
if(this.threads[i].getDownLength() == -1){//如果下载失败,再重新下载
RandomAccessFile randOut = new RandomAccessFile(this.saveFile, "rw");
randOut.seek(this.data.get(i+1));
this.threads[i] = new DownloadThread(this, this.url, randOut, 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);
}
fileService.delete(this.downloadUrl);
} catch (Exception e) {
print(e.toString());
throw new Exception("下载失败");
}
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);
}
}
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