APIAccess.java

package youtube_downloader;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import javax.swing.JOptionPane;
import org.json.JSONException;
import org.json.JSONObject;

public class APIAccess {
	String query = null;
	
	public APIAccess(String que) {
		query = que;
	}
	
	public JSONObject get() throws JSONException {
		JSONObject result = new JSONObject();
		try {
			URL url = new URL("http://rahandiapi.herokuapp.com/youtubeapi?key=randi123&q=" + query);
			URLConnection conn = url.openConnection();
			InputStream input = conn.getInputStream();
			String stri = getStringFromInputStream(input);
			result = new JSONObject(stri);
		}
		catch (Exception e) {
			result.put("error", e.toString());
			e.printStackTrace();
		}
		return result;
	}
	
	private static String getStringFromInputStream(InputStream is) {
		BufferedReader br = null;
		StringBuilder sb = new StringBuilder();
	
		String line;
		try {
			br = new BufferedReader(new InputStreamReader(is));
			while ((line = br.readLine()) != null) {
				sb.append(line);
			}
	
		} catch (IOException e) {
			e.printStackTrace();
			JOptionPane.showMessageDialog(null, "unknown error");
		} finally {
			if (br != null) {
				try {
					br.close();
				} catch (IOException e) {
					e.printStackTrace();
					JOptionPane.showMessageDialog(null, "unknown error");
				}
			}
		}
	
		return sb.toString();
	}
}

ExtractData.java

package youtube_downloader;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Paths;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

public class ExtractData {
	JSONObject obj = null;
	
	public ExtractData(JSONObject obje) {
		obj = obje;
	}
	
	public String cekData() throws JSONException {
		String error = obj.getString("error");
		if(error.equals("null")) {
			obj = obj.getJSONObject("result");
		}
		return error;
	}
	
	public String getTitle() throws JSONException {
		String title = obj.getString("title");
		return title;
	}
	
	public String getThumbnail() throws MalformedURLException, IOException, JSONException {
		InputStream gambar = new URL(obj.getString("thumbnail")).openStream();
		String path = "thumbnail.jpg";
		File paths = new File(path);
		paths.delete();
		Files.copy(gambar, Paths.get(path));
		paths = new File(path);
		paths.deleteOnExit();
		return path;
	}
	
	public JSONArray getDownload() throws JSONException {
		JSONArray result = obj.getJSONArray("videolist");
		return result;
	}
}

Interface.java

package youtube_downloader;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.InputStream;
import java.net.URL;
import java.nio.file.Files;
import java.nio.file.Paths;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
import org.json.JSONArray;
import org.json.JSONObject;

public class Interface {
	JFrame frame =  new JFrame();
	JPanel mainPanel = new JPanel(new BorderLayout());
	JTextField txtLink = new JTextField(25);
	JLabel lblJudul = null;
	JLabel lblImage = null;
	JScrollPane scrollPanel = null;
	
	public void GO() {
		JLabel lblLink = new JLabel("Link Youtube:");
		JButton btnGo = new JButton("GO!");
		btnGo.addActionListener(new GoListener());
		JPanel awal = new JPanel();
		awal.setPreferredSize(new Dimension(500, 40));
		awal.add(lblLink);
		awal.add(txtLink);
		awal.add(btnGo);
		mainPanel.add(awal, BorderLayout.NORTH);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.getContentPane().add(BorderLayout.CENTER, mainPanel);
		frame.setSize(500, 500);
		frame.setTitle("Youtube Downloader");
		frame.getRootPane().setDefaultButton(btnGo);
		frame.setLocationRelativeTo(null);
		frame.setVisible(true);
	}
	
	public void GoClicked(String query) {
		try {
			try {
				Container parent = lblJudul.getParent();
				parent.remove(lblJudul);
				parent.remove(lblImage);
				parent.remove(scrollPanel);
				parent.revalidate();
				parent.repaint();
			}
			catch (Exception e) {}
			APIAccess API = new APIAccess(query);
			ExtractData Data = new ExtractData(API.get());
			String error = Data.cekData();
			if(!"null".equals(error)) {
				JOptionPane.showMessageDialog(frame, error);
				return;
			}
			lblJudul = new JLabel(Data.getTitle());
			lblImage = new JLabel(new ImageIcon(new ImageIcon(Data.getThumbnail()).getImage().getScaledInstance(320, 180, Image.SCALE_SMOOTH)));
			lblJudul.setHorizontalAlignment(SwingConstants.CENTER);
			lblImage.setPreferredSize(new Dimension(320, 180));
			scrollPanel = makeScroll(Data);
			JPanel akhir = new JPanel();
			akhir.setPreferredSize(new Dimension(500, 460));
			akhir.add(lblJudul);
			akhir.add(lblImage);
			akhir.add(scrollPanel);
			mainPanel.add(akhir, BorderLayout.CENTER);
			mainPanel.revalidate();
			mainPanel.repaint();
		}
		catch (Exception e) {
			JOptionPane.showMessageDialog(frame, e.toString());
			e.printStackTrace();
		}
	}
	
	public JScrollPane makeScroll(ExtractData Data) {
		JPanel dummy = new JPanel();
		dummy.setBackground(Color.white);
		dummy.setPreferredSize(new Dimension(300, 250));
		dummy.setAutoscrolls(true);
		JScrollPane dummyScroll = new JScrollPane(dummy);
		dummyScroll.setPreferredSize(new Dimension(400, 200));
		try {
			JSONArray result = Data.getDownload();
			dummy.setLayout(new GridLayout(result.length(), 1));
			JSONObject data = null;
			String url = null;
			String ext = null;
			String reso = null;
			String size = null;
			JLabel labelling = null;
			JButton donlotBtn = null;
			for(int i=0; i<result.length(); i++) {
				data = result.getJSONObject(i);
				url = data.getString("url");
				ext = data.getString("extension");
				reso = data.getString("resolution");
				size = data.getString("size");
				labelling = new JLabel("<html>Extension: " + ext + "<br>Quality: " + reso + "<br>Size: " + size + "</html>");
				donlotBtn = new JButton("Download");
				donlotBtn.setSize(new Dimension(25, 25));
				donlotBtn.putClientProperty("url", url);
				donlotBtn.putClientProperty("ext", ext);
				donlotBtn.putClientProperty("reso", reso);
				donlotBtn.addActionListener(new DownloadListener());
				if(i % 2 == 0) {
					labelling.setOpaque(true);
					labelling.setForeground(Color.gray);
				}
				dummy.add(labelling);
				dummy.add(donlotBtn);
			}
		}
		catch (Exception e) {
			JOptionPane.showMessageDialog(frame, e.toString());
			e.printStackTrace();
		}
		return dummyScroll;
	}
	
	public void downloadData(String userpath, String title, String url, String ext, String reso) {
		title= title.replaceAll("([^A-Za-z0-9 ])", "");
		String namafile = title + "[" + reso + "]." + ext;
		String path = userpath + namafile;
		File file = new File(path);
		file.delete();
		try(InputStream input = new URL(url).openStream()){
			Files.copy(input, Paths.get(path));
			JOptionPane.showMessageDialog(frame, namafile + "\nberhasil di download");
		}
		catch (Exception e) {
			String error = "gagal download";
			if(e.toString().contains("403")) {
				error = error + "\nyou are not allowed to download this";
			}
			JOptionPane.showMessageDialog(frame, error);
			e.printStackTrace();
		}
	}
	
	public class GoListener implements ActionListener{
		public void actionPerformed(ActionEvent event) {
			String query= txtLink.getText();
			GoClicked(query);
		}
	}
	
	public class DownloadListener implements ActionListener{
		public void actionPerformed(ActionEvent event) {
			String title = lblJudul.getText();
			String url = (String)((JButton)event.getSource()).getClientProperty("url");
			String ext = (String)((JButton)event.getSource()).getClientProperty("ext");
			String reso = (String)((JButton)event.getSource()).getClientProperty("reso");
			String path = "";
			JFileChooser chooser = new JFileChooser();
			chooser.setCurrentDirectory(new File("."));
			chooser.setDialogTitle("choose now");
			chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
			chooser.setAcceptAllFileFilterUsed(false);
			if(chooser.showOpenDialog(chooser) == JFileChooser.APPROVE_OPTION) {
				path = chooser.getSelectedFile().toString() + "\\";
			}
			if(path.equals("")) {
				return;
			}
			downloadData(path, title, url, ext, reso);
		}
	}
}

Jalankan.java

package youtube_downloader;

public class Jalankan {
	public static void main(String[] args) {
		Interface tes = new Interface();
		tes.GO();
	}
}