If you send each download with one thread, which I recomend, You have severals possibilities.
Use of Future
and FutureTask
to wait until all the threads are done.
To use thread.join()
to wait until the thread stops.
Frage
My application will parse a XML file from my web server then download the files. My application will get the contents of "URL" from in XML file and download it using Common-IO's FileUtils. My problem is, how do I know that my download process is done or not. There is a lot of "URL" in my XML file.
Here is some part of my code:
private Proxy proxy = Proxy.NO_PROXY;
public void downloadLibrary()
{
System.out.println("Start downloading libraries from server...");
try
{
URL resourceUrl = new URL("http://www.example.com/libraries.xml");
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(resourceUrl.openConnection(proxy).getInputStream());
NodeList nodeLst = doc.getElementsByTagName("Contents");
for (int i = 0; i < nodeLst.getLength(); i++)
{
Node node = nodeLst.item(i);
if (node.getNodeType() == 1)
{
Element element = (Element)node;
String key = element.getElementsByTagName("Key").item(0).getChildNodes().item(0).getNodeValue();
File f = new File(launcher.getWorkingDirectory(), key);
downloadFile("http://www.example.com/" + key, f, "libraries");
}
}
}
catch(Exception e)
{
System.out.println("Error was found when trying to download libraries file " + e);
}
}
public void downloadFile(final String url, final File path, final String fileName)
{
SwingWorker<Void, Void> worker = new SwingWorker<Void, Void>()
{
@Override
protected Void doInBackground() throws Exception
{
launcher.println("Downloading file " + fileName + "...");
try
{
URL fileURL = new URL(url);
ReadableByteChannel rbc = Channels.newChannel(fileURL.openStream());
FileOutputStream fos = new FileOutputStream(path);
fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
}
catch(Exception e)
{
System.out.println("Cannot download file : " + fileName + " " + e);
}
return null;
}
@Override
public void done()
{
System.out.println(fileName + " had downloaded sucessfully");
}
};
worker.execute();
}
Lösung
If you send each download with one thread, which I recomend, You have severals possibilities.
Use of Future
and FutureTask
to wait until all the threads are done.
To use thread.join()
to wait until the thread stops.