java中Frame框架关闭按钮和框架居中的设置方法

import java.awt.Button;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.TextField;
import java.awt.Toolkit;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;

//让框架居中显示及Frame框架关闭按钮的功能实现
public class MyFrame extends Frame implements WindowListener {

	public MyFrame(){
		super("this is frame");  //设置窗口标题
		setSize(400, 300);   //设置窗口尺寸
		//获取屏幕的高度和宽度
		int w=this.getWidth();  //获取框架的宽度
		int h=this.getHeight();   //获取框架的高度
		Dimension screenSize=Toolkit.getDefaultToolkit().getScreenSize();     
		double screenWidth=screenSize.getWidth();  //获取屏幕的宽度
		double screenHeith=screenSize.getHeight();  //获取屏幕的高度
		
		int x=(int)(screenWidth-w)/2;    
		int y=(int)(screenHeith-h)/2;
		
		//设置框架显示的位置
		setLocation(x, y);
		
//		this.setBounds((int)((screenWidth)/2-this.getWidth()),(int)((screenHeith/2)-this.getHeight()), 200, 200);  // 100,100分别为距离x,y轴的距离，后面的x,y分别框架的长和宽
		this.setLayout(new FlowLayout());     //设置布局管理器为流布局管理器
        this.add(new TextField("hello welocme to java!"));
		this.addWindowListener(this);   //添加窗口监听器
		this.setVisible(true);         //设置窗口可见   true可见，false 不可见
	}
	public static void main(String[] args) {
		new MyFrame();   //实例化
	}

	public void windowOpened(WindowEvent e) {}
	
	public void windowClosing(WindowEvent e) 
	    {
		      e.getWindow().dispose();
		}  //关闭窗口方法
	
	public void windowClosed(WindowEvent e) {}
	
	public void windowIconified(WindowEvent e) {}
	
	public void windowDeiconified(WindowEvent e) {}

	public void windowActivated(WindowEvent e) {}

	public void windowDeactivated(WindowEvent e) {}

}