java使用layerpane设置背景图片

两种读图的方法

Image  grass=new ImageIcon("pure-grass.gif").getImage();

Image img=Toolkit.getDefaultToolkit().getImage("board.jpg");

让屏幕大小区匹配图片

bg=new ImageIcon("board1.jpg");
  JLabel lable=new JLabel(bg);
  imagePanel=(JPanel)getContentPane();
  //设置为透明
  imagePanel.setOpaque(false);
  imagePanel.setLayout(null);
  lable.setBounds(0,0,bg.getIconWidth(),bg.getIconHeight());
  getLayeredPane().add(lable,new Integer(Integer.MIN_VALUE)); 
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setSize(bg.getIconWidth(), bg.getIconHeight());

还有另一种方法，就是让图片伸展

附上带菜单和背景的完整代码

package fiveChess;

import java.awt.Button;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.HeadlessException;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;

//import chessTest.ChessBoard;
public class MainFrame extends JFrame{
	private ChessBoard chessBoard;
	private JMenuBar menubar;
	private JMenu sysmenu;
	private JMenuItem startMenuItem,exitMenuItem,backMenuItem;
	private Image bg;
	public MainFrame() throws HeadlessException {
		super("五子棋");
		//Container container=getContentPane();
		Dimension dimension=new Dimension(500, 500);
		setSize(dimension);
		setLocation(400,150);
		chessBoard=new ChessBoard();
		Container contentpane=this.getContentPane();
		
		//contentpane.add(chessBoard);
		
		Lis lis=new Lis();
		menubar=new JMenuBar();
		sysmenu=new JMenu("菜单");
		startMenuItem=new JMenuItem("重新开始");
		exitMenuItem=new JMenuItem("退出");
		backMenuItem=new JMenuItem("悔棋");
		
		startMenuItem.addActionListener(lis);
		exitMenuItem.addActionListener(lis);
		backMenuItem.addActionListener(lis);
		
		
		sysmenu.add(startMenuItem);
		sysmenu.add(exitMenuItem);
		sysmenu.add(backMenuItem);
		
		menubar.add(sysmenu);
		setJMenuBar(menubar);
		
		
		bg=new ImageIcon("board1.jpg").getImage();
		ImageIcon imageIcon=new ImageIcon(bg);
		JLabel lable=new JLabel(imageIcon);
		lable.setBounds(0, 0, dimension.width, dimension.height);
		getLayeredPane().add(lable,new Integer(Integer.MIN_VALUE));
		JPanel jp=(JPanel)this.getContentPane();
		jp.setOpaque(false);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		
		setVisible(true);
	}
	
	private class Lis implements ActionListener{
			public void actionPerformed(ActionEvent e){
				Object obj=e.getSource();
				if(obj==startMenuItem){
					System.out.println("重新开始");
					
					
				}
				else if(obj==exitMenuItem){
					System.out.println("退出");
					
					
				}
				else if(obj==backMenuItem){
					System.out.println("悔棋");
					
					
				}
				
				
			}
		
	}
	
	public static void main(String[] args){
		MainFrame mainframe=new MainFrame();
		
		
	}
	
	
	
}