Java 的 actionlistener怎么用啊

给你做了个样板

import java.awt.BorderLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;

public class JFrameDemo extends JFrame implements ActionListener{
int time=0;
JButton jb=new JButton("click me");
JLabel jl=new JLabel("No. of drinks ordered");
public JFrameDemo(){
this.setSize(900,600);
int width=Toolkit.getDefaultToolkit().getScreenSize().width;
int height=Toolkit.getDefaultToolkit().getScreenSize().height;
this.setLocation((width-900)/2,(height-600)/2);
this.setDefaultCloseOperation(EXIT_ON_CLOSE);
this.add(jb,BorderLayout.NORTH);
this.add(jl,BorderLayout.SOUTH);
jb.addActionListener(this);
this.setVisible(true);
}
public static void main(String[] args) {
new JFrameDemo();

}

public void actionPerformed(ActionEvent e) {
if(e.getSource()==jb){
time++;
jl.setText("No. of drinks ordered"+time);
}

}

}