java GUI编程：显示标签

本题目来自于《java程序设计--基础篇》的第12章。编写一个程序，实现在四个标签上显示四行文本，在每个标签上添加一条边界。

  思路分析：定义自己的类，这个类继承自JFrame,然后类的成员属性有：一个JPanel,四个JLabel.他们其实状态指向的地址都为空，在类的构造方法中再new出来。这四个标签都要添加到Panel里面！

import java.awt.*;
import javax.swing.*;

public class Ex12_5 extends JFrame {
	
	//定义一个Panle和四个标签
	JPanel jpanel = null;
	JLabel jlb1 = null;
	JLabel jlb2 = null;
	JLabel jlb3 = null;
	JLabel jlb4 = null;
	
	public Ex12_5() {
		
		//创建对象，
		jpanel = new JPanel();
		jlb1 = new JLabel("Department of Computer Science");
		jlb2 = new JLabel("School of Computing");
		jlb3 = new JLabel("Armstrong Atlantic State University");
		jlb4 = new JLabel("Tel:(912)921-6440");
		
		//让每个标签都显示出边框出来
		jlb1.setBorder(BorderFactory.createLineBorder(Color.BLACK));
		jlb2.setBorder(BorderFactory.createLineBorder(Color.BLACK));
		jlb3.setBorder(BorderFactory.createLineBorder(Color.BLACK));
		jlb4.setBorder(BorderFactory.createLineBorder(Color.BLACK));
		
		jpanel.setLayout(new GridLayout(4, 1));

		//将标签添加到panel
		jpanel.add(jlb1);
		jpanel.add(jlb2);
		jpanel.add(jlb3);
		jpanel.add(jlb4);
		
		//将panel添加到frame里面去
		this.add(jpanel);
	}
	
	public static void main(String[] args) {
		JFrame frame = new Ex12_5();
		frame.setTitle("显示标签");
		frame.setSize(250, 200);
		frame.setLocation(500, 200);
		frame.setVisible(true);
	}
}

运行效果如图：