Java Program to Download Files and Images From Server URL and Website to Local PC Full Project For Beginners

 

Here’s a complete file downloader example program with output, error checking, and command line argument checks:

package so.downloader;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URI;
import java.nio.file.Files;
import java.nio.file.Paths;

public class Application {
    public static void main(String[] args) throws MalformedURLException, IOException {
        if (2 != args.length) {
            System.out.println(String.format("USAGE: java -jar so-downloader.jar <source-URL> <target-filename>"));
            System.exit(1);
        }

        String sourceUrl = args[];
        String targetFilename = args[1];

        long bytesDownloaded = download(sourceUrl, targetFilename);

        System.out.println(String.format("Downloaded %d bytes from %s to %s.", bytesDownloaded, sourceUrl, targetFilename));
    }

    static long download(String sourceUrl, String targetFileName) throws MalformedURLException, IOException {
        try (InputStream in = URI.create(sourceUrl).toURL().openStream()) {
            return Files.copy(in, Paths.get(targetFileName));
        }
    }

}

As noted in the so-downloader repository README:

To run file download program:

java -jar so-downloader.jar <source-URL> <target-filename>

for example:

 

java -jar so-downloader.jar https://github.com/JanStureNielsen/so-downloader/archive/main.zip so-downloader-source.zip

 

 

When using Java 7+ use the following method to download a file from the Internet and save it to some directory:

private static Path download(String sourceURL, String targetDirectory) throws IOException
{
    URL url = new URL(sourceURL);
    String fileName = sourceURL.substring(sourceURL.lastIndexOf('/') + 1, sourceURL.length());
    Path targetPath = new File(targetDirectory + File.separator + fileName).toPath();
    Files.copy(url.openStream(), targetPath, StandardCopyOption.REPLACE_EXISTING);

    return targetPath;
}

Documentation here.

See also  Java Swing AWT Program to Build Currency Converter Using JSON API GUI Desktop App Full Project For Beginners

 

 

Another method shown here

 

public static void downloadFileFromURL(String urlString, File destination) {    
        try {
            URL website = new URL(urlString);
            ReadableByteChannel rbc;
            rbc = Channels.newChannel(website.openStream());
            FileOutputStream fos = new FileOutputStream(destination);
            fos.getChannel().transferFrom(rbc, , Long.MAX_VALUE);
            fos.close();
            rbc.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

 

 

Another Complete java program to download file from server

 

 

import java.io.*;
import java.net.*;

public class filedown {
    public static void download(String address, String localFileName) {
        OutputStream out = null;
        URLConnection conn = null;
        InputStream in = null;

        try {
            URL url = new URL(address);
            out = new BufferedOutputStream(new FileOutputStream(localFileName));
            conn = url.openConnection();
            in = conn.getInputStream();
            byte[] buffer = new byte[1024];

            int numRead;
            long numWritten = ;

            while ((numRead = in.read(buffer)) != -1) {
                out.write(buffer, , numRead);
                numWritten += numRead;
            }

            System.out.println(localFileName + "\t" + numWritten);
        } 
        catch (Exception exception) { 
            exception.printStackTrace();
        } 
        finally {
            try {
                if (in != null) {
                    in.close();
                }
                if (out != null) {
                    out.close();
                }
            } 
            catch (IOException ioe) {
            }
        }
    }

    public static void download(String address) {
        int lastSlashIndex = address.lastIndexOf('/');
        if (lastSlashIndex >=  &&
        lastSlashIndex < address.length() - 1) {
            download(address, (new URL(address)).getFile());
        } 
        else {
            System.err.println("Could not figure out local file name for "+address);
        }
    }

    public static void main(String[] args) {
        for (int i = ; i < args.length; i++) {
            download(args[i]);
        }
    }
}

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