String directoryName = Environment.getExternalStorageDirectory().toString()
+ "/filename";////文件保存路径
///传入参数:Context对象,下载地址, 文件保存路径;
DownloadTask downloadTask = new DownloadTask (this, mDownloadUrl, directoryName);
new Thread(downloadTask ).start();///////启动线程进行下载
////下载类
public class DownloadTask implements Runnable {
private long mDownloadedSize = 0;
private long mTotalSize;
private int mDownloadPercent;
private String mLocalPath;
private String mURL;
private Context mContext;
public DownloadTask (Context context, String url, String localPath) {
this.mLocalPath = localPath;
this.mURL = url;
this.mContext = context;
}
@Override
public void run() {
download();
};
////下载方法
protected boolean download() {
File file = new File(mLocalPath);
if (file.exists()) {
mDownloadedSize = file.length();
} else {
mDownloadedSize = 0;
}
Log.d(TAG, "mURL, " + mURL + " downloadedSize, " + mDownloadedSize);
HttpURLConnection httpConnection = null;
URL url = null;
try {
url = new URL(mUpgradeURL);
httpConnection = (HttpURLConnection) url.openConnection();
mTotalSize = httpConnection.getContentLength();
Log.d(TAG, "totalSize, " + mTotalSize);
if (mDownloadedSize == mTotalSize ) {
////////已下载到本地
return true;
} else if (mDownloadedSize > mTotalSize) {
if (!file.delete()) {
return false;
}
}
httpConnection.disconnect();
} catch (Exception e) {
e.printStackTrace();
return false;
} finally {
try {
if (httpConnection != null) {
httpConnection.disconnect();
}
} catch (Exception e) {
}
}
InputStream inStream = null;
RandomAccessFile randomAccessFile = null;
try {
httpConnection = (HttpURLConnection) url.openConnection();
httpConnection.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, " + "*/*");
httpConnection.setRequestProperty("Accept-Language", "zh-CN");
httpConnection.setRequestProperty("Referer", mUpgradeURL);
httpConnection.setRequestProperty("Charset", "UTF-8");
httpConnection.setRequestProperty("Range", "bytes=" + mDownloadedSize + "-");
httpConnection.setRequestProperty("Connection", "Keep-Alive");
inStream = httpConnection.getInputStream();
File saveFile = new File(mLocalPath);
randomAccessFile = new RandomAccessFile(saveFile, "rwd");
randomAccessFile.seek(mDownloadedSize);
int offset = 0;
int count = 0;
int perUnit = (int) mTotalSize / 1024 / 100;
byte[] buffer = new byte[1024];
while ((offset = inStream.read(buffer, 0, 1024)) != -1) {
randomAccessFile.write(buffer, 0, offset);
count++;
if (count == perUnit && mDownloadedSize < mTotalSize) {
mDownloadPercent = (int) (mDownloadedSize * 100 / mTotalSize);
////////下载百分百mDownloadPercent
count = 0;
}
mDownloadedSize += offset;
}
if (mDownloadedSize == mTotalSize ) {
/////////下载完成
}
Log.d(TAG, "download finished.");
return true;
} catch (Exception e) {
e.printStackTrace();
return false;
} finally {
try {
if (inStream != null) {
inStream.close();
}
if (httpConnection != null) {
httpConnection.disconnect();
}
if (randomAccessFile != null) {
randomAccessFile.close();
}
} catch (Exception e) {
}
}
}
}
android中支持多种文件类型的下载类,布布扣,bubuko.com
android中支持多种文件类型的下载类