Swing中让frame置于屏幕中央的实现方法,及添加图标

import  java.awt.Dimension;
import  java.awt.Image;
import  java.awt.Toolkit;

import  javax.swing.JFrame;


public   class  CenterFrame  extends  JFrame{
    private   static   final   long  serialVersionUID = 1L;
    public   static   void  main(String[] str){
        new  CenterFrame().setVisible( true );
    }
    public  CenterFrame() {
          //取屏幕大小
          Toolkit kit = Toolkit.getDefaultToolkit();
          Dimension screenSize = kit.getScreenSize();
          int  screenHeight = screenSize.height;
          int  screenWidth = screenSize.width;

          //置于屏幕中央
          setSize(screenWidth/2 , screenHeight/ 2 );
          setLocation(screenWidth/4 , screenHeight/ 4 );

          //添加图标
          Image img = kit.getImage("icon.gif" );
          setIconImage(img);
          setTitle("CenterFrame" );
        }

}