在jsp中使用response.getOutputStream()导致报错问题getOutputStream() has already been called for this response

<%@ page language="java" contentType="image/jpeg" %>
<%@ page import="java.awt.image.*,javax.imageio.*,java.io.*,java.awt.*" %>

<%
BufferedImage image = new BufferedImage(340,160,BufferedImage.TYPE_INT_RGB);

Graphics g = image.getGraphics();

g.fillRect(0, 0, 400, 400);

g.setColor(new Color(255,0,0));

g.fillArc(20,20,100,100,30,120);

g.setColor(new Color(0,255,0));

g.fillArc(20,20,100,100,150,120);

g.setColor(new Color(0,0,255));

g.fillArc(20,20,100,100,270,120);

g.setColor(new Color(0,0,0));

g.setFont(new Font("Arial Black",Font.PLAIN,16));

g.drawString("red:climb",200,60);
g.drawString("green:swim",200,100);
g.drawString("blue:jump",200,140);
g.dispose();

ImageIO.write(image,"jpg",response.getOutputStream());
//out.clear();
//out = pageContext.pushBody();
%>

今天使用JSP输出位图时，使用了response。getOutputStream()时出现了错误，

网上找到的解决办法是

out.clear();
out = pageContext.pushBody();

在jsp中执行上述两个话即可解决，具体原因目前不是很清晰，很多人说是JSP中使用getWriter和这里的getOutputStream冲突了，以后找到真正原因再补充