import java.awt.*;import java.awt.event.*;import javax.swing.*;public class hello extends JFrame{ public static void main(String args[]){ new hello().setVisible(true);}public void paint(Graphics g){ setSize(400,400);g.drawString("世界，你好",186,200); this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //点击关闭，则关闭并退出整个程序 //this.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);// 关闭当前窗口}}