Java生成登录随机验证码-蒲公英云

Java生成登录随机验证码

清疚 2022-03-28 10:00 413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>