可以使用
Java后端生成
验证码的方法,以下是一个简单的示例:
javaimportjava.awt.Color;importjava.awt.Font;importjava.awt.Graphics;importjava.awt.image.BufferedImage;importjava.util.Random;importjavax.imageio.ImageIO;importjavax.servlet.http.HttpServletRequest;importjavax.servlet.http.HttpServletResponse;importjavax.servlet.http.HttpSession;/* 生成验证码的工具类*/public class CaptchaUtil {private static final int WIDTH = 100; //验证码图片的宽度private static final int HEIGHT = 40; //验证码图片的高度private static final int CODE_LENGTH = 4; //验证码字符个数private static final int LINE_COUNT = 20; // 干扰线数量// 随机生成的字符集合private static final String CODE_SET = "0abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";// 随机数生成器private static final Random random = new Random();/* 生成验证码图片,并将验证码字符串存入session中** @param request* @param response* @return验证码字符串* @throws Exception*/public static String generateCaptcha(HttpServletRequest request, HttpServletResponse response) throws Exception {// 设置响应头信息response.setContentType("image/jpeg");response.setHeader("Pragma", "no-cache");response.setHeader("Cache-Control", "no-cache");response.setDateHeader("Expires", 0);// 创建一个图像对象BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);// 获取图形上下文对象Graphics g = image.getGraphics();// 设置背景色g.setColor(Color.WHITE);g.fillRect(0, 0, WIDTH, HEIGHT);// 设置字体g.setFont(new Font("Arial", Font.PLAIN, 20));// 生成随机字符串StringBuilder code = new StringBuilder();for (int i = 0; i < CODE_LENGTH; i++) {int index = random.nextInt(CODE_SET.length());char c = CODE_SET.charAt(index);code.append(c);g.setColor(new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255)));g.drawString(String.valueOf(c), 20 * i + 10, 25);}// 绘制干扰线for (int i = 0; i < LINE_COUNT; i++) {g.setColor(new Color(random.nextInt(255), random.nextInt(255), random.nextInt(255)));int x1 = random.nextInt(WIDTH);int y1 = random.nextInt(HEIGHT);int x2 = random.nextInt(WIDTH);int y2 = random.nextInt(HEIGHT);g.drawLine(x1, y1, x2, y2);}// 释放资源g.dispose();// 将验证码存入session中HttpSession session = request.getSession();session.setAttribute("captchaCode", code.toString());// 将图像输出到客户端ImageIO.write(image, "JPEG", response.getOutputStream());// 返回生成的验证码字符串return code.toString();}/* 校验验证码** @param request* @param code* 用户输入的验证码* @return true-验证码正确,false-验证码错误*/public static boolean validateCaptcha(HttpServletRequest request, String code) {HttpSession session = request.getSession();String captchaCode = (String) session.getAttribute("captchaCode");return captchaCode != null && captchaCode.equalsIgnoreCase(code);}}
使用方法:
在需要生成
验证码的地方调用 `generateCaptcha` 方法即可,例如:
java// 生成验证码String captchaCode = CaptchaUtil.generateCaptcha(request, response);
在需要
验证 验证码的地方调用 `validateCaptcha` 方法即可,例如:
java// 校验验证码if (CaptchaUtil.validateCaptcha(request, code)) {//验证码正确} else {//验证码错误}
其
中`code` 是用户输入的
验证码字符串。
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