download with java code is really slow

i wrote a bit of code that reads download links from a text file and downloads the videos using the copyURLToFile methode from apaches commons-io library and the download is really slow when im in my wlan. when i put in an internet stick is is about 6 times faster although the stick got 4mbit and my wlan is 8 mbit. i also tried to do it without the commons-io library but the problem is the same. normally im downloading 600-700 kb/s in my wlan but with java it only downloads with about 50 kb/s. With the internet stick its about 300 kb/s. Do you know what the Problem could be?

thanks in advance

//Edit: Here is the code but i dont think it has anything to do with this and what do you mean with network it policies?

FileInputStream fstream = new FileInputStream(linksFile);
    DataInputStream in = new DataInputStream(fstream);
    BufferedReader br = new BufferedReader(new InputStreamReader(in));

    String link;
    String name;

    while ((link = br.readLine()) != null) {
        name = br.readLine();
        FileUtils.copyURLToFile(new URL(link), new File("videos/"+name+".flv"));;
        S开发者_如何学Goystem.out.println(link);
    }

This isn't likely to be a Java problem.

The code you've posted actually doesn't do any IO over the network - it just determines a URL and passes it to (presumably Apache Commons') FileUtils.copyURLToFile. As usual with popular third-party libraries, if this method had a bug in it that caused slow throughput in all but the most unusual situations, it would already have been identified (and hopefully fixed).

Thus the issue is going to lie elsewhere. Do you get the expected speeds when accessing resource through normal HTTP methods (e.g. in a browser)? If not, then there's a universal problem at the OS level. Otherwise, I'd have a look at the policies on your network.

Two possible causes spring to mind:

• The obvious one is some sort of traffic shaping - your network deprioritises the packets that come from your Java app (for an potentially arbitrary reason). You'd need to see hwo this is configured and look at its logs to see if this is the case.
• The problem resides with DNS. If Java's using a primary server that's either blocked or incredibly slow, then it could take up to a few seconds to convert that URL to an IP address and begin the actual transfer. I had a similar problem once when a firewall was silently dropping packets to one server and it took three seconds (per lookup!) for the Java process to switch to the secondary server.

In any case, it's almost certainly not the Java code that's at fault.

The FileUtils.copyURLToFile internals uses a buffer to read. Increasing the value of the buffer could speed up the download, but that seems not possible.