Java生成登录随机验证码

清疚 2022-03-28 10:00 338阅读 0赞

**验证码工具类：** VerifyUtil.java

import java.awt.*;
    import java.awt.image.BufferedImage;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.Random;
    
    public class VerifyUtil { 
        // 验证码字符集
        private static final char[] CHARS = { 
                '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
                'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
                'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
                'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
                'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z'};
        // 字符数量
        private static final int SIZE = 4;
        // 干扰线数量
        private static final int LINES = 5;
        // 宽度
        private static final int WIDTH = 80;
        // 高度
        private static final int HEIGHT = 40;
        // 字体大小
        private static final int FONT_SIZE = 30;
    
        /** * 生成随机验证码及图片 */
        public static Map<String, Object> createImage() { 
            StringBuffer sb = new StringBuffer();
            // 1.创建空白图片
            BufferedImage image = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
            // 2.获取图片画笔
            Graphics graphic = image.getGraphics();
            // 3.设置画笔颜色
            graphic.setColor(Color.LIGHT_GRAY);
            // 4.绘制矩形背景
            graphic.fillRect(0, 0, WIDTH, HEIGHT);
            // 5.画随机字符
            Random ran = new Random();
            for (int i = 0; i < SIZE; i++) { 
                // 取随机字符索引
                int n = ran.nextInt(CHARS.length);
                // 设置随机颜色
                graphic.setColor(getRandomColor());
                // 设置字体大小
                graphic.setFont(new Font(null, Font.BOLD + Font.ITALIC, FONT_SIZE));
                // 画字符
                graphic.drawString(CHARS[n] + "", i * WIDTH / SIZE, HEIGHT * 2 / 3);
                // 记录字符
                sb.append(CHARS[n]);
            }
            // 6.画干扰线
            for (int i = 0; i < LINES; i++) { 
                // 设置随机颜色
                graphic.setColor(getRandomColor());
                // 随机画线
                graphic.drawLine(ran.nextInt(WIDTH), ran.nextInt(HEIGHT), ran.nextInt(WIDTH), ran.nextInt(HEIGHT));
            }
            // 7.返回验证码和图片
            Map<String, Object> map = new HashMap<>();
            //验证码
            map.put("code", sb.toString());
            //图片
            map.put("image", image);
            return map;
        }
    
        /** * 随机取色 */
        public static Color getRandomColor() { 
            Random ran = new Random();
            return new Color(ran.nextInt(256), ran.nextInt(256), ran.nextInt(256));
        }
    }

**获取验证码**

@GetMapping("/verify-code")
    public void getCode(HttpServletResponse response) throws Exception{ 
        Map<String, Object> map = VerifyUtil.createImage();
        //将图片输出给浏览器
        BufferedImage image = (BufferedImage) map.get("image");
        response.setContentType("image/png");
        OutputStream os = response.getOutputStream();
        ImageIO.write(image, "png", os);
    }

**页面**

<!DOCTYPE html>
    <html lang="en">
    <head>
        <meta charset="UTF-8">
        <title>获取验证码</title>
    </head>
    <body onload="getVerify()">
    <h1>点击图片切换验证码</h1><img id="img-verify" src="" alt="更换验证码" height="36" onclick="getVerify()">
    </body>
    <script> //获取验证码 function getVerify(){ document.getElementById("img-verify").src="/verify-code?"+Math.random(); } </script>
    </html>