请各位高手给我看下这个java程序

来源：百度知道 编辑：UC知道 时间：2024/05/09 09:31:59
import javax.swing.*;
public class qq extends JFrame {
JComboBox monthbox=new JComboBox();
JComboBox yearbox=new JComboBox();

public void Expiration(){
super( "Expiration Date");
setSize(220,90);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel pane=new JPanel();
JLabel exp=new JLabel("Expiration Date:");
pane.add(exp);
int i;
for(i=1;i<13;i++)
monthbox.addItem(i);
for(i=2000;i<2010;i++)
yearbox.addItem(i);

pane.add(monthbox);
pane.add(yearbox);
setContentPane(pane);
show();
}
public static void main (String[] args) {
Expiration ct=new Expiration();
}

}
生成结果：
-------------Configuration: qq - JDK version 1.5.0_05 <Default> - <Default>--------------------
C:\Program Files\Xinox Software\JCreatorV4\MyProjects\qq\src\

你应该这样写

import javax.swing.*;

public class Expiration extends JFrame {
JComboBox monthbox = new JComboBox();

JComboBox yearbox = new JComboBox();

public Expiration() {
super("Expiration Date");
setSize(220, 90);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel pane = new JPanel();
JLabel exp = new JLabel("Expiration Date:");
pane.add(exp);
int i;
for (i = 1; i < 13; i++)
monthbox.addItem(i);
for (i = 2000; i < 2010; i++)
yearbox.addItem(i);

pane.add(monthbox);
pane.add(yearbox);
setContentPane(pane);
show();
}

public static void main(String[] args) {
Expiration ct = new Expiration();
}

}

－－－－
你想创建的是Expiration 类吧，class 写成qq有问题了

事实上是 --- super()表示调用父类的构造函数,但只能在本类的构造函数中调用,也就说,super()只能写在你的构造函数里面,.
而你写在一个public void 的方法里,所以会出错