Java基础：实现简易购物车功能的代码示例

import java.awt.*;
import java.awt.event.*;
class ShopFrame extends Frame implements ActionListener
{   Label label1,label2,label3,label4;
    Button button1,button2,button3,button4,button5;
    TextArea text;
    Panel panel1,panel2;
    static float sum=0.0f;
    ShopFrame(String s)
    { super(s);
      setLayout(new BorderLayout());
      label1=new Label("面纸：3元",Label.LEFT);
      label2=new Label("钢笔：5元",Label.LEFT);
      label3=new Label("书：10元",Label.LEFT);
      label4=new Label("袜子：8元",Label.LEFT);
      button1=new Button("加入购物车");
      button2=new Button("加入购物车");
      button3=new Button("加入购物车");
      button4=new Button("加入购物车");
      button5=new Button("查看购物车");
      text=new TextArea("商品有："+"\n",5,10);
      text.setEditable(false);
      addWindowListener(new WindowAdapter()
                        {  public void windowClosing(WindowEvent e)
                           {  System.exit(0);
                           }
                        }
                        );
      button1.addActionListener(this);
      button2.addActionListener(this);