/**
* 只用三步生成验证码图片
*/
//1.new工具类
VerifyCode code = new VerifyCode();
//2.创建图片
BufferedImage image = code.createImage();
//验证码
System.out.println(code.getText());
//3.验证码图片格式
ImageIO.write(image,"jpg",response.getOutputStream());