Menampilkan data yang bersesuain di JComboBox

Application.java

/**
 *
 * @author akhmad
 */
public class Application extends javax.swing.JFrame {

    private Connection connection;
    
    /**
     * Creates new form Application
     */
    public Application() {
        try {
            initComponents();
            cmbNama.addActionListener(new ComboBoxListener());
            
            Class.forName("com.mysql.jdbc.Driver");
            connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/db_case", "root", "3092");
            
            ambilData(connection);
            
        } catch (ClassNotFoundException ex) {
            Logger.getLogger(Application.class.getName()).log(Level.SEVERE, null, ex);
        } catch (SQLException se) {
            Logger.getLogger(Application.class.getName()).log(Level.SEVERE, null, se);
        }
    }

    public void ambilData(Connection conn) throws SQLException{
        String query = "SELECT * FROM tb_barang";
        Statement stmt = conn.createStatement();
        ResultSet rs = stmt.executeQuery(query);
        
        List<Barang> list = new ArrayList<>();
        
        cmbNama.removeAllItems();
        
        while (rs.next()) {
            Barang barang = new Barang();
            
            barang.setId(rs.getInt("id"));
            barang.setNama(rs.getString("nama"));
            barang.setHarga(rs.getInt("harga"));
            
            list.add(barang);
        }
        
        // Tampilkan data ke combobox
        DefaultComboBoxModel  model = new DefaultComboBoxModel();
        for (Barang brg : list) {
            model.addElement(brg);
        }
        cmbNama.setModel(model);
    }
    
    class ComboBoxListener implements ActionListener {

        @Override
        public void actionPerformed(ActionEvent e) {
            Barang barang = (Barang) cmbNama.getSelectedItem();
            
            if (barang != null) {
                txtHarga.setText(String.valueOf(barang.getHarga()));
            }
            
        }
        
    }