java使用驗證碼進行登入驗證

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隨機產生4位驗證碼,將產生的4位元字字母數字放入session

private static void outputVerifyCode(HttpServletRequest request,            HttpServletResponse response) throws Exception {        BufferedImage img = new BufferedImage(68, 22, 1);        Graphics g = img.getGraphics();        Random r = new Random();        Color c = new Color(200, 150, 255);        g.setColor(c);        g.fillRect(0, 0, 68, 22);        StringBuffer sb = new StringBuffer();        char[] ch = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();        int len = ch.length;        for (int i = 0; i < 4; i++) {            int index = r.nextInt(len);            g.setColor(new Color(r.nextInt(88), r.nextInt(188), r.nextInt(255)));            g.setFont(new Font("Arial", 2, 22));            g.drawString(String.valueOf(ch[index]), i * 15 + 3, 18);            sb.append(ch[index]);        }        request.getSession().setAttribute("verifypic", sb);        ImageIO.write(img, "JPG", response.getOutputStream());    }

比對將登入提交的驗證碼和session裡的驗證碼同時轉為小寫並比較

private boolean chekcVerifycode(String inputStr, String correctStr) {        return inputStr.toLowerCase().equals(correctStr.toLowerCase());    }

 

java使用驗證碼進行登入驗證