jsp画图
<%@ page language="java" contentType="text/html; charset=gbk"pageEncoding="gbk" import="javax.imageio.*,java.awt.*,java.awt.image.*"%>
<%
int width=400;
int height=400;
BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
Graphics g=image.getGraphics();
g.setColor(Color.red);
g.drawLine(20,20,220,20);
g.setColor(Color.white);
g.dispose();
ImageIO.write(image,"jpg",response.getOutputStream());
out.clear();
out = pageContext.pushBody();
%>
背景色是漆黑的,怎么设置背景色