验证码（一）

验证码（一）

@RequestMapping("/image")
    public void image(HttpServletRequest request, HttpServletResponse response) throws IOException {
        request.setCharacterEncoding("utf-8");

        BufferedImage bfi = new BufferedImage(80, 25, BufferedImage.TYPE_INT_RGB);
        Graphics g = bfi.getGraphics();
        g.fillRect(0, 0, 80, 25);

        //验证码字符范围
        char[] ch = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789".toCharArray();
        Random r = new Random();
        int index;
        StringBuffer sb = new StringBuffer(); //保存字符串
        for (int i = 0; i < 4; i++) {
            index = r.nextInt(ch.length);
            g.setColor(new Color(r.nextInt(255), r.nextInt(255), r.nextInt(255)));
            Font font = new Font("宋体", 30, 20);
            g.setFont(font);
            g.drawString(ch[index] + "", (i * 20) + 2, 23);
            sb.append(ch[index]);
        }

        // 添加噪点
        int area = (int) (0.02 * 60 * 25);
        for (int i = 0; i < area; ++i) {
            int x = (int) (Math.random() * 80);
            int y = (int) (Math.random() * 25);
            bfi.setRGB(x, y, (int) (Math.random() * 255));
        }

        //设置验证码中的干扰线
        for (int i = 0; i < 3; i++) {
            //随机获取干扰线的起点和终点
            int xstart = (int) (Math.random() * 80);
            int ystart = (int) (Math.random() * 25);
            int xend = (int) (Math.random() * 80);
            int yend = (int) (Math.random() * 25);
            g.setColor(interLine(1, 255));
            g.drawLine(xstart, ystart, xend, yend);
        }
        HttpSession session = request.getSession();  //保存到session
        session.setAttribute("verificationCode", sb.toString());
        ImageIO.write(bfi, "JPG", response.getOutputStream());  //写到输出流
    }

    private static Color interLine(int Low, int High) {
        if (Low > 255)
            Low = 255;
        if (High > 255)
            High = 255;
        if (Low < 0)
            Low = 0;
        if (High < 0)
            High = 0;
        int interval = High - Low;
        int r = Low + (int) (Math.random() * interval);
        int g = Low + (int) (Math.random() * interval);
        int b = Low + (int) (Math.random() * interval);
        return new Color(r, g, b);
    }

    @RequestMapping("/checkCode")
    @ResponseBody
    public Map<String,Object> checkCode(String code,HttpSession session){
        Map<String,Object> map=new HashMap<>();

        String verificationCode = (String) session.getAttribute("verificationCode");
        if(verificationCode.equalsIgnoreCase(code)){
            map.put("valid",true);
        }else{
            map.put("valid",false);
        }
        return map;
    }