Java Swing dependent JList

In this section, you will learn how to create a dependent list using java swing

In this section, you will learn how to create a dependent list using java swing

Java Swing dependent JList

In this section, you will learn how to create a dependent list using java swing

In the given code, we have created three lists. In the first list we have displayed the names of the databases present in mysql database and when the user selects a particular database from the first list, the tables present under that database should be displayed on second list. And finally on selecting a particular table from second list, the column names present in the selected table will get displayed on the third list.

Here is the code:

import java.awt.*;
import java.sql.*;
import javax.swing.*;
import javax.swing.event.*;

public class JListExample extends JFrame {

	JPanel panel = new JPanel();

	public JListExample() {
		panel.setLayout(null);
		try {
			Class.forName("com.mysql.jdbc.Driver");
			Connection con = DriverManager.getConnection(
					"jdbc:mysql://localhost:3306/", "root", "root");
			Statement st = con.createStatement();
			ResultSet rs = st.executeQuery("show databases");
			String data = "";
			while (rs.next()) {
				data += rs.getString("Database") + " ";
			}
			String db[] = data.split(" ");
			final JList list1 = new JList(db);
			JScrollPane pane1 = new JScrollPane(list1);
			final DefaultListModel model = new DefaultListModel();
			final JList list2 = new JList(model);
			JScrollPane pane2 = new JScrollPane(list2);
			final DefaultListModel model2 = new DefaultListModel();
			final JList list3 = new JList(model2);
			JScrollPane pane3 = new JScrollPane(list3);
			list1.addListSelectionListener(new ListSelectionListener() {
				public void valueChanged(ListSelectionEvent e) {
					if (!e.getValueIsAdjusting()) {
						model.clear();
						String st = (String) list1.getSelectedValue();
						System.out.println(st);
						try {
							Connection conn = DriverManager.getConnection(
									"jdbc:mysql://localhost:3306/" + st,
									"root", "root");
							DatabaseMetaData meta = conn.getMetaData();
							ResultSet res = meta.getTables(null, null, "%",
									null);
							String tableNames = "";
							while (res.next()) {
								tableNames = res.getString(3) + " ";
								model.addElement(tableNames);
							}
							model.removeElement("mysql");
						} catch (Exception ex) {
						}
					}
				}
			});
			list2.addListSelectionListener(new ListSelectionListener() {
				public void valueChanged(ListSelectionEvent e) {
					if (!e.getValueIsAdjusting()) {
						model2.clear();
						String str = (String) list2.getSelectedValue();
						String s = (String) list1.getSelectedValue();
						try {
							Connection conn = DriverManager.getConnection(
									"jdbc:mysql://localhost:3306/" + s, "root",
									"root");
							Statement stmt = conn.createStatement();
							ResultSet res = stmt.executeQuery("SELECT * FROM "
									+ str + "");
							ResultSetMetaData md = res.getMetaData();
							int col = md.getColumnCount();
							for (int i = 1; i <= col; i++) {
								String col_name = md.getColumnName(i);
								model2.addElement(col_name);
							}
						} catch (Exception ex) {
						}
					}
				}
			});
			pane1.setBounds(10, 10, 100, 100);
			pane2.setBounds(120, 10, 100, 100);
			pane3.setBounds(230, 10, 100, 100);
			panel.add(pane1);
			panel.add(pane2);
			panel.add(pane3);
			add(panel);
			setSize(400, 200);
			setVisible(true);
		} catch (Exception e) {
		}
	}

	public static void main(String[] args) {
		new JListExample();
	}
}

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