Graphics2D画图时背景颜色设置

package test;

import java.awt.AlphaComposite;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;

public class DrawGraphics {

 /**
  * @param args
  */
 public static void main(String[] args) throws Exception{
  int width=800;
  int height=800;  
  File file = new File("e:a.jpg");
  BufferedImage bi = new BufferedImage(width, height,
    BufferedImage.TYPE_INT_RGB);//RGB形式
  Graphics2D g2 = (Graphics2D) bi.getGraphics();
  g2.setBackground(Color.WHITE);//设置背景色
  g2.clearRect(0, 0, width, height);//通过使用当前绘图表面的背景色进行填充来清除指定的矩形。
  g2.setPaint(Color.BLUE);//设置画笔,设置Paint属性
  g2.drawOval(0, 0, 80, 80);
  ImageIO.write(bi, "jpeg", file);
  g2.dispose();
  System.out.println("test");

 }

}