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:

<span class="hljs-keyword">package</span> so.downloader;

<span class="hljs-keyword">import</span> java.io.IOException;
<span class="hljs-keyword">import</span> java.io.InputStream;
<span class="hljs-keyword">import</span> java.net.MalformedURLException;
<span class="hljs-keyword">import</span> java.net.URI;
<span class="hljs-keyword">import</span> java.nio.file.Files;
<span class="hljs-keyword">import</span> java.nio.file.Paths;

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

        String sourceUrl = args[<span class="hljs-number">0</span>];
        String targetFilename = args[<span class="hljs-number">1</span>];

        <span class="hljs-keyword">long</span> bytesDownloaded = download(sourceUrl, targetFilename);

        System.out.println(String.format(<span class="hljs-string">"Downloaded %d bytes from %s to %s."</span>, bytesDownloaded, sourceUrl, targetFilename));
    }

    <span class="hljs-function"><span class="hljs-keyword">static</span> <span class="hljs-keyword">long</span> <span class="hljs-title">download</span><span class="hljs-params">(String sourceUrl, String targetFileName)</span> <span class="hljs-keyword">throws</span> MalformedURLException, IOException </span>{
        <span class="hljs-keyword">try</span> (InputStream in = URI.create(sourceUrl).toURL().openStream()) {
            <span class="hljs-keyword">return</span> Files.copy(in, Paths.get(targetFileName));
        }
    }

}

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[0];

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>

1 2	java -jar so-downloader.jar <source-URL> <target-filename>

for example:

java -jar so-downloader.jar https:<span class="hljs-comment">//github.com/JanStureNielsen/so-downloader/archive/main.zip so-downloader-source.zip</span>

1	java -jar so-downloader.jar https:<span class="hljs-comment">//github.com/JanStureNielsen/so-downloader/archive/main.zip so-downloader-source.zip</span>

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

<span class="hljs-function"><span class="hljs-keyword">private</span> <span class="hljs-keyword">static</span> Path <span class="hljs-title">download</span><span class="hljs-params">(String sourceURL, String targetDirectory)</span> <span class="hljs-keyword">throws</span> IOException
</span>{
    URL url = <span class="hljs-keyword">new</span> URL(sourceURL);
    String fileName = sourceURL.substring(sourceURL.lastIndexOf(<span class="hljs-string">'/'</span>) + <span class="hljs-number">1</span>, sourceURL.length());
    Path targetPath = <span class="hljs-keyword">new</span> File(targetDirectory + File.separator + fileName).toPath();
    Files.copy(url.openStream(), targetPath, StandardCopyOption.REPLACE_EXISTING);

    <span class="hljs-keyword">return</span> targetPath;
}

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.

Another method shown here

<span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">downloadFileFromURL</span><span class="hljs-params">(String urlString, File destination)</span> </span>{    
        <span class="hljs-keyword">try</span> {
            URL website = <span class="hljs-keyword">new</span> URL(urlString);
            ReadableByteChannel rbc;
            rbc = Channels.newChannel(website.openStream());
            FileOutputStream fos = <span class="hljs-keyword">new</span> FileOutputStream(destination);
            fos.getChannel().transferFrom(rbc, <span class="hljs-number">0</span>, Long.MAX_VALUE);
            fos.close();
            rbc.close();
        } <span class="hljs-keyword">catch</span> (IOException e) {
            e.printStackTrace();
        }
    }

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, 0, Long.MAX_VALUE);

fos.close();

rbc.close();

} catch (IOException e) {

e.printStackTrace();

}

Another Complete java program to download file from server

<span class="hljs-keyword">import</span> java.io.*;
<span class="hljs-keyword">import</span> java.net.*;

<span class="hljs-keyword">public</span> <span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">filedown</span> </span>{
    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">download</span><span class="hljs-params">(String address, String localFileName)</span> </span>{
        OutputStream out = <span class="hljs-keyword">null</span>;
        URLConnection conn = <span class="hljs-keyword">null</span>;
        InputStream in = <span class="hljs-keyword">null</span>;

        <span class="hljs-keyword">try</span> {
            URL url = <span class="hljs-keyword">new</span> URL(address);
            out = <span class="hljs-keyword">new</span> BufferedOutputStream(<span class="hljs-keyword">new</span> FileOutputStream(localFileName));
            conn = url.openConnection();
            in = conn.getInputStream();
            <span class="hljs-keyword">byte</span>[] buffer = <span class="hljs-keyword">new</span> <span class="hljs-keyword">byte</span>[<span class="hljs-number">1024</span>];

            <span class="hljs-keyword">int</span> numRead;
            <span class="hljs-keyword">long</span> numWritten = <span class="hljs-number">0</span>;

            <span class="hljs-keyword">while</span> ((numRead = in.read(buffer)) != -<span class="hljs-number">1</span>) {
                out.write(buffer, <span class="hljs-number">0</span>, numRead);
                numWritten += numRead;
            }

            System.out.println(localFileName + <span class="hljs-string">"\t"</span> + numWritten);
        } 
        <span class="hljs-keyword">catch</span> (Exception exception) { 
            exception.printStackTrace();
        } 
        <span class="hljs-keyword">finally</span> {
            <span class="hljs-keyword">try</span> {
                <span class="hljs-keyword">if</span> (in != <span class="hljs-keyword">null</span>) {
                    in.close();
                }
                <span class="hljs-keyword">if</span> (out != <span class="hljs-keyword">null</span>) {
                    out.close();
                }
            } 
            <span class="hljs-keyword">catch</span> (IOException ioe) {
            }
        }
    }

    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">download</span><span class="hljs-params">(String address)</span> </span>{
        <span class="hljs-keyword">int</span> lastSlashIndex = address.lastIndexOf(<span class="hljs-string">'/'</span>);
        <span class="hljs-keyword">if</span> (lastSlashIndex >= <span class="hljs-number">0</span> &&
        lastSlashIndex < address.length() - <span class="hljs-number">1</span>) {
            download(address, (<span class="hljs-keyword">new</span> URL(address)).getFile());
        } 
        <span class="hljs-keyword">else</span> {
            System.err.println(<span class="hljs-string">"Could not figure out local file name for "</span>+address);
        }
    }

    <span class="hljs-function"><span class="hljs-keyword">public</span> <span class="hljs-keyword">static</span> <span class="hljs-keyword">void</span> <span class="hljs-title">main</span><span class="hljs-params">(String[] args)</span> </span>{
        <span class="hljs-keyword">for</span> (<span class="hljs-keyword">int</span> i = <span class="hljs-number">0</span>; i < args.length; i++) {
            download(args[i]);
        }
    }
}

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 = 0;

while ((numRead = in.read(buffer)) != -1) {

out.write(buffer, 0, 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 >= 0 &&

lastSlashIndex < address.length() - 1) {

download(address, (new URL(address)).getFile());

}

else {

System.err.println("Could not figure out local file name for "+address);

}

for (int i = 0; i < args.length; i++) {

download(args[i]);

}

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