wget

wget direct / multithread / singlethread java download library.

Support single thread, single thread with download continue / resume, and multithread downloads.

Exceptions

Here is a three kind of exceptions.

1. Fatal exception. all RuntimeException's We shall stop application

2. DownloadError (extends RuntimeException) We unable to process following url and shall stop to download it. It may be rised by problem with local file.

3. DownloadMultipartError (extends DownloadError) We unable to download multhread source. Shall stop downloading and parse each Parts exceptions.

4. DownloadInterrceptedError (extends DownloadError) Current thread was interrcepted by main app (you). So handle it your self ;)

5. DownloadIOError (extends DownloadError) Some simple exceptoins, like Timeout exceptions we handle internaly, and retry part / download automaticaly without user interrraction. But some hudge errors, like problems with file on server (HTTP 403) we pass to the App. It may stop download, or auto update download URL and automaticaly retry the download without any user interaction.

Example Direct Download

package com.github.axet.wget;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;

import com.github.axet.wget.WGet;

public class Example {

    public static void main(String[] args) {
        try {
            // choise internet url (ftp, http)
            URL url = new URL("http://www.dd-wrt.com/routerdb/de/download/D-Link/DIR-300/A1/ap61.ram/2049");
            // choise target folder or filename "/Users/axet/Downloads/ap61.ram"
            File target = new File("/Users/axet/Downloads/");
            // initialize wget object
            WGet w = new WGet(url, target);
            // single thread download. will return here only when file download
            // is complete (or error raised).
            w.download();
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (RuntimeException allDownloadExceptions) {
            allDownloadExceptions.printStackTrace();
        }
    }
}

Application Managed Multithread Download

package com.github.axet.wget;

import java.io.File;
import java.net.URL;
import java.util.concurrent.atomic.AtomicBoolean;

import com.github.axet.wget.info.DownloadInfo;
import com.github.axet.wget.info.DownloadInfo.Part;
import com.github.axet.wget.info.DownloadInfo.Part.States;
import com.github.axet.wget.info.ex.DownloadMultipartError;

public class Example {

    AtomicBoolean stop = new AtomicBoolean(false);
    DownloadInfo info;
    long last;

    public void run() {
        try {
            Runnable notify = new Runnable() {
                @Override
                public void run() {
                    // notify app or save download state
                    // you can extract information from DownloadInfo info;
                    switch (info.getState()) {
                    case EXTRACTING:
                    case EXTRACTING_DONE:
                    case DONE:
                        System.out.println(info.getState());
                        break;
                    case RETRYING:
                        System.out.println(info.getState() + " " + info.getDelay());
                        break;
                    case DOWNLOADING:
                        long now = System.currentTimeMillis();
                        if (now - 1000 > last) {
                            last = now;

                            String parts = "";

                            for (Part p : info.getParts()) {
                                if (p.getState().equals(States.DOWNLOADING)) {
                                    parts += String.format("Part#%d(%.2f) ", p.getNumber(),
                                            p.getCount() / (float) p.getLength());
                                }
                            }

                            System.out.println(String.format("%.2f %s", info.getCount() / (float) info.getLength(),
                                    parts));
                        }
                        break;
                    default:
                        break;
                    }
                }
            };

            // choise file
            URL url = new URL("http://download.virtualbox.org/virtualbox/4.2.4/VirtualBox-4.2.4-81684-OSX.dmg");
            // initialize url information object
            info = new DownloadInfo(url);
            // extract infromation from the web
            info.extract(stop, notify);
            // enable multipart donwload
            info.enableMultipart();
            // Choise target file
            File target = new File("/Users/axet/Downloads/VirtualBox-4.2.4-81684-OSX.dmg");
            // create wget downloader
            WGet w = new WGet(info, target);
            // will blocks until download finishes
            w.download(stop, notify);
        } catch (DownloadMultipartError e) {
            for (Part p : e.getInfo().getParts()) {
                Throwable ee = p.getException();
                if (ee != null)
                    ee.printStackTrace();
            }
        } catch (RuntimeException e) {
            throw e;
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args) {
        Example e = new Example();
        e.run();
    }

}

Cetral Maven Repo

<dependency>
  <groupId>com.github.axet</groupId>
  <artifactId>wget</artifactId>
  <version>1.2.7</version>
</dependency>