java spring boot生成图片验证码

@ApiOperation("生成验证码")
    @GetMapping("/getVerifyCode")
    public void getVerificationCode(@RequestParam String id, HttpServletResponse response) {
    
    

        try {
    
    

            int width=200;

            int height=69;

            BufferedImage verifyImg=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);

            //生成对应宽高的初始图片

            String randomText = GeneratorSureNumberUtil.drawRandomText(width,height,verifyImg);
            //把验证码放入redis中
//            String code = UUIDGenerator.getCode()+"admin";
            redisUtil.set(id,randomText,60*1L);

            //单独的一个类方法，出于代码复用考虑，进行了封装。
            // 功能是生成验证码字符并加上噪点，干扰线，返回值为验证码字符

            //request.getSession().setAttribute("key",code);
            response.setHeader("Content-Disposition", "fileName="+ id);
            response.setContentType("image/png");//必须设置响应内容类型为图片，否则前台不识别
            OutputStream os = response.getOutputStream(); //获取文件输出流

            ImageIO.write(verifyImg,"png",os);//输出图片流

            os.flush();

            os.close();//关闭流

        } catch (IOException e) {
    
    

            System.out.println(e);

            e.printStackTrace();

        }

    }

工具类

public class GeneratorSureNumberUtil {
    
    
    public static String drawRandomText(int width, int height, BufferedImage verifyImg) {
    
    

        Graphics2D graphics = (Graphics2D)verifyImg.getGraphics();

        graphics.setColor(Color.WHITE);//设置画笔颜色-验证码背景色

        graphics.fillRect(0, 0, width, height);//填充背景

        graphics.setFont(new Font("微软雅黑", Font.BOLD, 40));

        //数字和字母的组合

        String baseNumLetter= "123456789abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";

        StringBuffer sBuffer = new StringBuffer();

        int x = 10;  //旋转原点的 x 坐标

        String ch = "";

        Random random = new Random();

        for(int i = 0;i < 4;i++){
    
    

            graphics.setColor(getRandomColor());

            //设置字体旋转角度

            int degree = random.nextInt() % 30;  //角度小于30度

            int dot = random.nextInt(baseNumLetter.length());

            ch = baseNumLetter.charAt(dot) + "";

            sBuffer.append(ch);

            //正向旋转

            graphics.rotate(degree * Math.PI / 180, x, 45);

            graphics.drawString(ch, x, 45);

            //反向旋转

            graphics.rotate(-degree * Math.PI / 180, x, 45);

            x += 48;

        }


        //画干扰线

        for (int i = 0; i <6; i++) {
    
    

            // 设置随机颜色

            graphics.setColor(getRandomColor());

            // 随机画线

            graphics.drawLine(random.nextInt(width), random.nextInt(height),

                    random.nextInt(width), random.nextInt(height));

        }

        //添加噪点

        for(int i=0;i<30;i++){
    
    

            int x1 = random.nextInt(width);

            int y1 = random.nextInt(height);

            graphics.setColor(getRandomColor());

            graphics.fillRect(x1, y1, 2,2);

        }

        return sBuffer.toString();

    }

    /**
     * 随机取色
     */

    private static Color getRandomColor() {
    
    

        Random ran = new Random();

        Color color = new Color(ran.nextInt(256),

                ran.nextInt(256), ran.nextInt(256));

        return color;

    }

}