校验码

来源：互联网发布：美妆软件哪个好编辑：程序博客网时间：2024/05/01 14:36
/**     * <校验码>     *     * @param request     * @param response     * @throws IOException     * @author Administrator     * @date 2010-5-12     */    private void verifyCode(HttpServletRequest request,                            HttpServletResponse response) throws IOException {        response.setContentType("image/jpeg");        response.setHeader("Pragma", "No-cache");        response.setHeader("Cache-Control", "no-cache");        response.setDateHeader("Expires", 0);        HttpSession session = request.getSession();        // 在内存中创建图象        int width = 60, height = 18;        BufferedImage image = new BufferedImage(width, height,                BufferedImage.TYPE_INT_RGB);        // 获取图形上下文        Graphics g = image.getGraphics();        // 设定背景色        g.setColor(new Color(0xffffff));        g.fillRect(0, 0, width, height);        String mapTable[] = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};        StringBuffer rands = new StringBuffer();        Random ran = new Random();        for (int i = 0; i < 4; ++i) {            rands.append(mapTable[ran.nextInt(mapTable.length)]);        }        String rand = rands.toString();        // 将认证码存入SESSION        session.setAttribute("rand", rand);        // 将认证码显示到图象中        g.setColor(Color.black);        g.setFont(new Font("Times New Roman", Font.BOLD, 16));        String Str = rand.substring(0, 1);        g.drawString(Str, 13 * 0 + 6, 12);        Str = rand.substring(1, 2);        g.drawString(Str, 13 * 1 + 6, 17);        Str = rand.substring(2, 3);        g.drawString(Str, 13 * 2 + 6, 15);        Str = rand.substring(3, 4);        g.drawString(Str, 13 * 3 + 6, 15);        // Str = rand.substring(4,5);        // g.drawString(Str,65,15);        // 随机产生88个干扰点，使图象中的认证码不易被其它程序探测到        Random random = new Random();        for (int i = 0; i < 3; i++) {            Color c5 = new Color(random.nextInt(200), random.nextInt(200),                    random.nextInt(200));            g.setColor(c5);            int x = random.nextInt(width / 2);            int y = random.nextInt(height / 2);            int xl = random.nextInt(60);            int yl = random.nextInt(20);            g.drawLine(x, y, x + xl, y + yl);        }        // Random random = new Random();        for (int i = 0; i < 68; i++) {            Color c6 = new Color(random.nextInt(250), random.nextInt(250),                    random.nextInt(200));            g.setColor(c6);            int x = random.nextInt(width);            int y = random.nextInt(height);            g.drawOval(x, y, 0, 0);        }        // 图象生效        g.dispose();        // 输出图象到页面        ServletOutputStream responseOutputStream = response.getOutputStream();        // 输出图象到页面        ImageIO.write(image, "JPEG", responseOutputStream);        // 以下关闭输入流！        responseOutputStream.flush();        responseOutputStream.close();        image = null;    }
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