spring封装VerifyCodeUtil工具类，生成图片验证码

傷城~ 2022-10-09 15:22 231阅读 0赞

登录页面经常需要生成图片验证码  
本文提供一个封装好的验证码生成工具类，可以直接调用生成图片验证码，返回BASE64编码的图片字节字符串。

**项目结构：**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RBYXJvbjY2Ng_size_16_color_FFFFFF_t_70]

**下面是实战代码：**

### 第一步： ###

新建工程，引入springboot依赖，创建启动类，创建controller接口  
VerifyCodeController.class:  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RBYXJvbjY2Ng_size_16_color_FFFFFF_t_70 1]

### 第二步：导入工具类 ###

package com.tzq.test.util;
    
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import javax.imageio.ImageIO;
    import java.awt.*;
    import java.awt.image.BufferedImage;
    import java.io.IOException;
    import java.io.OutputStream;
    import java.util.Random;
    
    
    public class VerifyCodeUtil { 
        private final static Logger logger = LoggerFactory.getLogger(VerifyCodeUtil.class);
    
        // 生成随机数的源
        private final static String VERIFY_CODE_SRC = "0123456789";
    
        /** * 生成验证码 * * @param width 图片宽度 * @param height 图片长度 * @param verifyCodeSize 验证码个数 * @param outputStream 输出流 * @return 验证码 */
        public static String generateVerifyCode(int width, int height, int verifyCodeSize, OutputStream outputStream) { 
            // 生成 verifyCodeSize 个随机数
            String verifyCode = VerifyCodeUtil.getRandomVerifyCode(verifyCodeSize, VERIFY_CODE_SRC);
            logger.debug("【验证码】生成 {} 位验证码：{}", verifyCodeSize, verifyCode);
    
            // 创建指定长宽的图片
            BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            Graphics2D graphics2D = bufferedImage.createGraphics();
            graphics2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    
            // 设置边框颜色
            Color randomColor = VerifyCodeUtil.getRandomColor(100, 150);
            graphics2D.setColor(Color.GRAY);
            graphics2D.fillRect(0, 0, width, height);
    
            // 设置背景颜色
            randomColor = VerifyCodeUtil.getRandomColor(200, 250);
            graphics2D.setColor(randomColor);
            graphics2D.fillRect(0, 2, width, height - 3);
    
            // 设置字体
            graphics2D.setColor(VerifyCodeUtil.getRandomColor(100, 150));
            graphics2D.setFont(new Font("Consolas", Font.ITALIC, (int) (height * 0.9)));
    
            //绘制干扰线
            VerifyCodeUtil.drawInterferenceLine(graphics2D, width, height);
    
            // 添加噪点
            VerifyCodeUtil.drawNoise(bufferedImage, width, height);
    
            // 扭曲图片
            VerifyCodeUtil.twist(graphics2D, width, height, randomColor);
    
            // 写入验证码
            VerifyCodeUtil.writeVerifyCode(graphics2D, verifyCode, width, height);
    
            try { 
                graphics2D.dispose();
                ImageIO.write(bufferedImage, "jpg", outputStream);
                outputStream.flush();
            } catch (IOException e) { 
                e.printStackTrace();
                logger.error("【验证码】生成异常：{}", e);
            }
    
            return verifyCode;
        }
    
        /** * 写入验证码 * * @param graphics2D * @param verifyCode * @param width * @param height */
        private static void writeVerifyCode(Graphics2D graphics2D, String verifyCode, int width, int height) { 
            Random rand = new Random();
            char[] chars = verifyCode.toCharArray();
            for (int i = 0; i < verifyCode.length(); i++) { 
                // 为每个验证码指定不同的颜色
                graphics2D.setColor(VerifyCodeUtil.getRandomColor(80, 150));
    
                // 旋转验证码
                // FIXME 旋转后的验证码辨识度太低，待完善
    // AffineTransform affineTransform = new AffineTransform();
    // double angle = Math.PI / 8 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1);
    // affineTransform.setToRotation(angle, (new Integer(width).doubleValue() / verifyCode.length()) * i, height * 0.1 / 2);
    // graphics2D.setTransform(affineTransform);
    
                // 绘制字符数组
                graphics2D.drawChars(chars, i, 1, (int) (width / (double) (verifyCode.length() + 2) * (i + 1)), (int) (height * 0.75));
            }
        }
    
        /** * 绘制噪点 * * @param image * @param width * @param height */
        private static void drawNoise(BufferedImage image, int width, int height) { 
            // 噪声率
            float yawpRate = 0.1f;
            int area = (int) (yawpRate * width * height);
            for (int i = 0; i < area; i++) { 
                int x = (int) (Math.random() * width);
                int y = (int) (Math.random() * height);
                int rgb = VerifyCodeUtil.getRandomIntColor();
                image.setRGB(x, y, rgb);
            }
        }
    
        /** * 绘制干扰线 * * @param graphics2D * @param width * @param height */
        private static void drawInterferenceLine(Graphics2D graphics2D, int width, int height) { 
            // 设置线条的颜色
            graphics2D.setColor(VerifyCodeUtil.getRandomColor(160, 200));
            // 20条干扰线
            for (int i = 0; i < 20; i++) { 
                int x1 = (int) (Math.random() * width * 0.7);
                int y1 = (int) (Math.random() * height * 0.7);
                graphics2D.drawLine(x1, y1, (int) (x1 + x1 * 0.3), (int) (y1 + y1 * 0.3));
            }
        }
    
        /** * 扭曲图片 * * @param graphics * @param width * @param height * @param color */
        private static void twist(Graphics graphics, int width, int height, Color color) { 
            int period = (int) ((Math.random() * height * 0.3) + height * 0.2);
            for (int i = 0; i < width; i++) { 
                double sin = (double) (period >> 1) * Math.sin(i / (double) period + Math.PI);
                graphics.copyArea(i, 0, 1, height, 0, (int) sin);
                graphics.setColor(color);
                graphics.drawLine(i, (int) sin, i, 0);
                graphics.drawLine(i, (int) sin + height, i, height);
            }
        }
    
        /** * 产生随机颜色，但指定范围 * * @param fc * @param bc * @return */
        private static Color getRandomColor(int fc, int bc) { 
            if (fc > 255) { 
                fc = 255;
            } else if (bc > 255) { 
                bc = 255;
            }
    
            int r = fc + (int) (Math.random() * (bc - fc));
            int g = fc + (int) (Math.random() * (bc - fc));
            int b = fc + (int) (Math.random() * (bc - fc));
    
            return new Color(r, g, b);
        }
    
        /** * 获取 int 类型颜色 * * @return */
        private static int getRandomIntColor() { 
            int[] rgb = new int[3];
            for (int i = 0; i < 3; i++) { 
                rgb[i] = (int) (Math.random() * 255);
            }
    
            int color = 0;
            for (int c : rgb) { 
                color = color << 8;
                color = color | c;
            }
    
            return color;
        }
    
        /** * 生成随机数字符串，指定大小和源 * * @param verifyCodeSize * @param verifyCodeSrc * @return */
        private static String getRandomVerifyCode(int verifyCodeSize, String verifyCodeSrc) { 
            StringBuffer stringBuffer = new StringBuffer(verifyCodeSize);
            for (int i = 0; i < verifyCodeSize; i++) { 
                stringBuffer.append(verifyCodeSrc.charAt((int) (Math.random() * verifyCodeSrc.length())));
            }
            return stringBuffer.toString();
        }
    
        /** * 生成验证码 * * @param verifyCodeSize 验证码个数 * @return 验证码 */
        public static String generateVerifyCode(int verifyCodeSize) { 
            // 生成 verifyCodeSize 个随机数
            String verifyCode = VerifyCodeUtil.getRandomVerifyCode(verifyCodeSize, VERIFY_CODE_SRC);
            logger.debug("【验证码】生成 {} 位验证码：{}", verifyCodeSize, verifyCode);
    
            return verifyCode;
        }
    
    }

### 第三步测试 ###

启动服务，打开浏览器：  
[http://localhost:8058/getVerifyCode?width=100&height=50&verfyCodeSize=4][http_localhost_8058_getVerifyCode_width_100_height_50_verfyCodeSize_4]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RBYXJvbjY2Ng_size_16_color_FFFFFF_t_70 2]  
返回值为BASE64编码的图片字节字符串，前端使用时需要加前缀：data:image/jpeg;base64。  
打开一个base64编码转换为图片的网址：[http://tool.chinaz.com/tools/imgtobase][http_tool.chinaz.com_tools_imgtobase]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RBYXJvbjY2Ng_size_16_color_FFFFFF_t_70 3]  
看到生成验证码成功。

> 项目源码地址：[https://gitee.com/tang-zhiqian0808/learning-code/tree/master/testVerifyCode][https_gitee.com_tang-zhiqian0808_learning-code_tree_master_testVerifyCode]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RBYXJvbjY2Ng_size_16_color_FFFFFF_t_70]: /images/20221005/50ddcee1326645c4b67e7a3337081f8f.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RBYXJvbjY2Ng_size_16_color_FFFFFF_t_70 1]: /images/20221005/e3581003852742d69b02df8a51ed8211.png
[http_localhost_8058_getVerifyCode_width_100_height_50_verfyCodeSize_4]: http://localhost:8058/getVerifyCode?width=100&height=50&verfyCodeSize=4
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RBYXJvbjY2Ng_size_16_color_FFFFFF_t_70 2]: /images/20221005/9090dcb7b8924062a208138c4a40c6cc.png
[http_tool.chinaz.com_tools_imgtobase]: http://tool.chinaz.com/tools/imgtobase
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L1RBYXJvbjY2Ng_size_16_color_FFFFFF_t_70 3]: /images/20221005/c82e8beb59ad4ac792243c79cec075d6.png
[https_gitee.com_tang-zhiqian0808_learning-code_tree_master_testVerifyCode]: https://gitee.com/tang-zhiqian0808/learning-code/tree/master/testVerifyCode