java事件处理

addActionListener(ActionListener listen1)

actionPerformed(ActionEvent e)

public Object getSource();//返回事件源的上转型对象的引用
public String getActionCommand()//返回一个相关的“命令”字符串，比如这个ActionEvent是文本框，那就是返回他的文本内容

class Component extends JFrame{
    JTextField test1;
    JButton button1;
    JTextArea testArea1;
    JRadioButton radioButton1,radioButton2;
    ButtonGroup group1;
    Component(){
        init();
        setVisible(true);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    void init(){
        setLayout(new FlowLayout());
        test1=new JTextField(8);
        button1=new JButton("huang");
        testArea1=new JTextArea(8,24);
        add(test1);
        add(button1);
        add(new JScrollPane(testArea1));
        AListener a=new AListener(test1,button1,testArea1);
        test1.addActionListener(a);//需要import java.awt.event.ActionListener;
        button1.addActionListener(a);
    }
}

class AListener implements ActionListener{
    JTextField test1;
    JButton button1;
    JTextArea testArea1;
    AListener(JTextField test,JButton button,JTextArea testArea){
        test1=test;
        button1=button;
        testArea1=testArea;
    }
    public void actionPerformed(ActionEvent e){
        String a=test1.getText();
        testArea1.append(a+"的长度"+a.length());
    }
}