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Android 斷點續傳下載
斷點續傳下載，其實就是記錄下原來下載的位置，然後從那個位置開始下載就是了。
代碼如下。
/**
* 作用：斷點續傳下載<BR>
* 作者：peijiangping<BR>
* 日期：2011-6-11
*/
public static int doDownloadTheFile_test(String strPath, String filePath,
String filename, int mode, long size, Handler handler) {
//file.size()即可得到原來下載文件的大小
//下載路徑
String url = strPath;
// 設置代理
Header header = null;
if (mode == 2) {
//移動內網的時候使用代理
url = format_CMWAP_URL(strPath);
header = new BasicHeader("X-Online-Host",
format_CMWAP_ServerName(strPath));
}
HttpResponse response = null;
// 用來獲取下載文件的大小
HttpResponse response_test = null;
try {
HttpClient client = new DefaultHttpClient();
HttpClient client_test = new DefaultHttpClient();
HttpGet request = new HttpGet(url);
HttpGet request_test = new HttpGet(url);
if (header != null) {
request.addHeader(header);
}
response_test = client_test.execute(request_test);
//獲取需要下載文件的大小
long fileSize = response_test.getEntity().getContentLength();
// 驗證下載文件的完整性
if (fileSize != 0 && fileSize == size) {
return 1;
}
//設置下載的數據位置XX字節到XX字節
Header header_size = new BasicHeader("Range", "bytes=" + size + "-"
+ fileSize);
request.addHeader(header_size);
response = client.execute(request);
InputStream is = response.getEntity().getContent();
if (is == null) {
throw new RuntimeException("stream is null");
}
SDCardUtil.createFolder(filePath);
//獲取文件對象，開始往文件裏麵寫內容
File myTempFile = new File(filePath + "/" + filename);
RandomAccessFile fos = new RandomAccessFile(myTempFile, "rw");
//從文件的size以後的位置開始寫入，其實也不用，直接往後寫就可以。有時候多線程下載需要用
fos.seek(size);
byte buf[] = new byte[1024];
long downloadfilesize = 0;
do {
int numread = is.read(buf);
if (numread <= 0) {
break;
}
fos.write(buf, 0, numread);
if (handler != null) {
Message msg = new Message();
downloadfilesize += numread;
double percent = (double) (downloadfilesize + size)
/ fileSize;
msg.obj = String.valueOf(percent);
handler.sendMessage(msg);// 更新下載進度百分比
}
} while (true);
is.close();
} catch (Exception ex) {
ex.printStackTrace();
return -1;
}
return 1;
}
最後更新：2017-04-03 18:52:12