Java Download File from URL

Today we will learn how to download a file from URL in java. We can use java.net.URL openStream() method to download file from URL in java program. We can use Java NIO Channels or Java IO InputStream to read data from the URL open stream and then save it to file.

Java Download File from URL

Here is the simple java download file from URL example program. It shows both ways to download file from URL in java.

JavaDownloadFileFromURL.java

package com.journaldev.files;

import java.io.BufferedInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.URL;
import java.nio.channels.Channels;
import java.nio.channels.ReadableByteChannel;

public class JavaDownloadFileFromURL {

    public static void main(String[] args) {
        String url = "https://www.journaldev.com/sitemap.xml";
        
        try {
            downloadUsingNIO(url, "/Users/pankaj/sitemap.xml");
            
            downloadUsingStream(url, "/Users/pankaj/sitemap_stream.xml");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void downloadUsingStream(String urlStr, String file) throws IOException{
        URL url = new URL(urlStr);
        BufferedInputStream bis = new BufferedInputStream(url.openStream());
        FileOutputStream fis = new FileOutputStream(file);
        byte[] buffer = new byte[1024];
        int count=0;
        while((count = bis.read(buffer,0,1024)) != -1)
        {
            fis.write(buffer, 0, count);
        }
        fis.close();
        bis.close();
    }

    private static void downloadUsingNIO(String urlStr, String file) throws IOException {
        URL url = new URL(urlStr);
        ReadableByteChannel rbc = Channels.newChannel(url.openStream());
        FileOutputStream fos = new FileOutputStream(file);
        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
        fos.close();
        rbc.close();
    }

}

downloadUsingStream: In this method of java download file from URL, we are using URL openStream method to create the input stream. Then we are using a file output stream to read data from the input stream and write to the file.

downloadUsingNIO: In this download file from URL method, we are creating byte channel from URL stream data. Then use the file output stream to write it to file.

You can use any of these methods to download the file from URL in java program. If you are looking for performance, then do some analysis by using both methods and see what suits your need.