public class Download implements Serializable {
private static final int START = 1; // 开始下载
private static final int PUBLISH = 2; // 更新进度
private static final int PAUSE = 3; // 暂停下载
private static final int CANCEL = 4; // 取消下载
private static final int ERROR = 5; // 下载错误
private static final int SUCCESS = 6; // 下载成功
private static final int GOON = 7; // 继续下载
private static ExecutorService mThreadPool; // 线程池
static {
mThreadPool = Executors.newFixedThreadPool(5); // 默认5个
}
private int mDownloadId; // 下载id
private String mFileName; // 本地保存文件名
private String mUrl; // 下载地址
private String mLocalPath; // 本地存放目录
private boolean isPause = false; // 是否暂停
private boolean isCanceled = false; // 是否手动停止下载
private OnDownloadListener mListener; // 监听器
/**
* 配置下载线程池的大小
* @param maxSize 同时下载的最大线程数
*/
public static void configDownloadTheadPool(int maxSize) {
mThreadPool = Executors.newFixedThreadPool(maxSize);
}
/**
* 添加下载任务
* @param downloadId 下载任务的id
* @param url 下载地址
* @param localPath 本地存放地址
*/
public Download(int downloadId, String url, String localPath) {
if (!new File(localPath).exists()) {
new File(localPath).mkdirs();
}
Log.log("下载地址；" + url);
mDownloadId = downloadId;
mUrl = url;
String[] tempArray = url.split("/");
mFileName = tempArray[tempArray.length-1];
mLocalPath = localPath;
}
/**
* 设置监听器
* @param listener 设置下载监听器
* @return this
*/
public Download setOnDownloadListener(OnDownloadListener listener) {
mListener = listener;
return this;
}
/**
* 获取文件名
* @return 文件名
*/
public String getFileName() {
return mFileName;
}
/**
* 开始下载
* params isGoon是否为继续下载
*/
public void start(final boolean isGoon) {
// 处理消息
final Handler handler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case ERROR:
mListener.onError(mDownloadId);
break;
case CANCEL:
mListener.onCancel(mDownloadId);
break;
case PAUSE:
mListener.onPause(mDownloadId);
break;
case PUBLISH:
mListener.onPublish(mDownloadId, Long.parseLong(msg.obj.toString()));
break;
case SUCCESS:
mListener.onSuccess(mDownloadId);
break;
case START:
mListener.onStart(mDownloadId, Long.parseLong(msg.obj.toString()));
break;
case GOON:
mListener.onGoon(mDownloadId, Long.parseLong(msg.obj.toString()));
break;
}
}
};
// 真正开始下载
mThreadPool.execute(new Runnable() {
@Override
public void run() {
download(isGoon,handler);
}
});
}
/**
* 下载方法
* @param handler 消息处理器
*/
private void download(boolean isGoon, Handler handler) {
Message msg = null;
Log.log("开始下载。。。");
try {
RandomAccessFile localFile = new RandomAccessFile(new File(
mLocalPath + File.separator + mFileName), "rwd");
DefaultHttpClient client = new DefaultHttpClient();
client.setParams(getHttpParams());
HttpGet get = new HttpGet(mUrl);
long localFileLength = getLocalFileLength();
final long remoteFileLength = getRemoteFileLength();
long downloadedLength = localFileLength;
// 远程文件不存在
if (remoteFileLength == -1l) {
Log.log("下载文件不存在...");
localFile.close();
handler.sendEmptyMessage(ERROR);
return;
}
// 本地文件存在
if (localFileLength > -1l && localFileLength
Log.log("本地文件存在...");
localFile.seek(localFileLength);
get.addHeader("Range", "bytes=" + localFileLength + "-"
+ remoteFileLength);
}
msg = Message.obtain();
// 如果不是继续下载
if(!isGoon) {
// 发送开始下载的消息并获取文件大小的消息
msg.what = START;
msg.obj = remoteFileLength;
}else {
msg.what = GOON;
msg.obj = localFileLength;
}
handler.sendMessage(msg);
HttpResponse response = client.execute(get);
int httpCode = response.getStatusLine().getStatusCode();
if (httpCode >= 200 && httpCode <= 300) {
InputStream in = response.getEntity().getContent();
byte[] bytes = new byte[1024];
int len = -1;
while (-1 != (len = in.read(bytes))) {
localFile.write(bytes, 0, len);
downloadedLength += len;
// Log.log((int)(downloadedLength/(float)remoteFileLength * 100));
if ((int)(downloadedLength/(float)remoteFileLength * 100) % 10 == 0) {
// 发送更新进度的消息
msg = Message.obtain();
msg.what = PUBLISH;
msg.obj = downloadedLength;
handler.sendMessage(msg);
// Log.log(mDownloadId + "已下载" + downloadedLength);
}
// 暂停下载， 退出方法
if (isPause) {
// 发送暂停的消息
handler.sendEmptyMessage(PAUSE);
Log.log("下载暂停...");
break;
}
// 取消下载， 删除文件并退出方法
if (isCanceled) {
Log.log("手动关闭下载。。");
localFile.close();
client.getConnectionManager().shutdown();
new File(mLocalPath + File.separator + mFileName)
.delete();
// 发送取消下载的消息
handler.sendEmptyMessage(CANCEL);
return;
}
}
localFile.close();
client.getConnectionManager().shutdown();
// 发送下载完毕的消息
if(!isPause) handler.sendEmptyMessage(SUCCESS);
}
} catch (Exception e) {
// 发送下载错误的消息
handler.sendEmptyMessage(ERROR);
}
}
/**
* 暂停/继续下载
* param pause 是否暂停下载
* 暂停 return true
* 继续 return false
*/
public synchronized boolean pause(boolean pause) {
if(!pause) {
Log.log("继续下载");
isPause = false;
start(true); // 开始下载
}else {
Log.log("暂停下载");
isPause = true;
}
return isPause;
}
/**
* 关闭下载， 会删除文件
*/
public synchronized void cancel() {
isCanceled = true;
if(isPause) {
new File(mLocalPath + File.separator + mFileName)
.delete();
}
}
/**
* 获取本地文件大小
* @return 本地文件的大小 or 不存在返回-1
*/
public synchronized long getLocalFileLength() {
long size = -1l;
File localFile = new File(mLocalPath + File.separator + mFileName);
if (localFile.exists()) {
size = localFile.length();
}
Log.log("本地文件大小" + size);
return size <= 0 ? -1l : size;
}
/**
* 获取远程文件打下 or 不存在返回-1
* @return
*/
public synchronized long getRemoteFileLength() {
long size = -1l;
try {
DefaultHttpClient client = new DefaultHttpClient();
client.setParams(getHttpParams());
HttpGet get = new HttpGet(mUrl);
HttpResponse response = client.execute(get);
int httpCode = response.getStatusLine().getStatusCode();
if (httpCode >= 200 && httpCode <= 300) {
size = response.getEntity().getContentLength();
}
client.getConnectionManager().shutdown();
} catch (Exception e) {
e.printStackTrace();
}
Log.log("远程文件大小" + size);
return size;
}
/**
* 设置http参数 不能设置soTimeout
* @return HttpParams http参数
*/
private static HttpParams getHttpParams() {
HttpParams params = new BasicHttpParams();
HttpProtocolParams.setContentCharset(params, HTTP.UTF_8);
HttpProtocolParams.setUseExpectContinue(params, true);
HttpProtocolParams
.setUserAgent(
params,
"Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2041.4 Safari/537.36");
ConnManagerParams.setTimeout(params, 4000);
HttpConnectionParams.setConnectionTimeout(params, 4000);
return params;
}
/**
* 关闭下载线程池
*/
public static void closeDownloadThread() {
if(null != mThreadPool) {
mThreadPool.shutdownNow();
}
}
public interface OnDownloadListener {
public void onStart(int downloadId, long fileSize); // 回调开始下载
public void onPublish(int downloadId, long size); // 回调更新进度
public void onSuccess(int downloadId); // 回调下载成功
public void onPause(int downloadId); // 回调暂停
public void onError(int downloadId); // 回调下载出错
public void onCancel(int downloadId); // 回调取消下载
public void onGoon(int downloadId, long localSize); // 回调继续下载
}
}
如何调用，如下：
Download d = new Download(1, "http://baidu.com/test.zip","/sdcard/download/");
d.setOnDownloadListener(new Download.OnDownloadListener() {
@Override
public void onSuccess(int downloadId) {
System.out.println(downloadId + "下载成功");
}
@Override
public void onStart(int downloadId, long fileSize) {
System.out.println(downloadId + "开始下载，文件大小：" + fileSize);
}
@Override
public void onPublish(int downloadId, long size) {
System.out.println("更新文件" + downloadId + "大小：" + size);
}
@Override
public void onPause(int downloadId) {
System.out.println("暂停下载" + downloadId);
}
@Override
public void onGoon(int downloadId, long localSize) {
System.out.println("继续下载" + downloadId);
}
@Override
public void onError(int downloadId) {
System.out.println("下载出错" + downloadId);
}
@Override
public void onCancel(int downloadId) {
System.out.println("取消下载" + downloadId);
}
});
d.start(false);
原文：http://my.oschina.net/oppo4545/blog/310099
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