java监听多个组件

import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.event.*;
import javax.swing.*;

public class ButtonInfoShowDemo1 extends JFrame implements ActionListener{

    JButton but1;
    JButton but2;
    JTextField tex;

    ButtonInfoShowDemo1(String sTitle){
        super(sTitle);
        initComponents();
    }

    public void initComponents(){
        this.setSize(300,100);

        JPanel pan = new JPanel();
        pan.setBackground(Color.yellow);
        pan.setLayout(new FlowLayout(FlowLayout.LEFT));

        //but1按钮
        but1 = new JButton("B1");
        but1.addActionListener(this);
        pan.add(but1);
        //but2按钮
        but2 = new JButton("B2");
        but2.addActionListener(this);
        pan.add(but2);
        //tex编辑框
        tex = new JTextField("",20);
        tex.setEditable(false);
        pan.add(tex);

        this.add(pan);
    }

    public void actionPerformed(ActionEvent e){
        if(e.getSource() == but1){
            tex.setText("B1被按下");
        }
        else if(e.getSource() == but2){
            tex.setText("B2被按下");
        }
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ButtonInfoShowDemo1 f = new ButtonInfoShowDemo1("简单图形界面");
        f.pack();
        f.setVisible(true);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

}