Java实现随机验证码和验证码图片渲染功能

﹏ヽ暗。殇╰゛Y 2023-01-20 14:53 307阅读 0赞

## 0.注意事项： ##

1.  图片格式（宽、高）、干扰线及数量在工具类的成员变量配置
2.  验证码验证。验证码生成后是存储在session中的，使用相同的属性名（类似key）即可取出，然后进行比对

## 1. 验证码生成工具类 ##

package com.jbp.util;
    
    import java.awt.*;
    import java.awt.image.BufferedImage;
    import java.util.Random;
    
    /** * @ClassName: OptimizeVerificationCodeUtil * @description: 验证码生产工具类优化版 * @author: JiangBeiPing * @create: 2021-05-12 10:12 * @Version: 1.0 **/
    public class OptimizeVerificationCodeUtil { 
    
        /** * 验证码图片 */
        private BufferedImage image;
    
        /** * 验证码 */
        private String verificationCode;
    
        /** * 生成的验证码的类型（目前的业务类型只需要数字类型） */
        private static char[] codeSequence = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9'};
    
        /** * 存入Session的验证码的属性名称 */
        public static final String SESSION_VERIFICATION_CODE = "validateCode";
    
        /** * 设置验证码图片的宽度 */
        private static final int WIDTH = 600;
    
        /** * 设置验证码图片的高度 */
        private static final int HEIGHT = 200;
    
        /** * 设置验证码字符的个数 */
        private static final int CODE_COUNT = 4;
    
        /** * 设置验证码图片干扰线的数量 */
        private static final int INTERFERING_LINE_COUNT = 160;
    
        private OptimizeVerificationCodeUtil() { 
            // 初始化过程中生产并渲染验证码图片
            init();
        }
    
        /** * 对外提供的本工具类的实例 * * @return 工具类的实例 */
        public static OptimizeVerificationCodeUtil instance() { 
            return new OptimizeVerificationCodeUtil();
        }
    
        /** * 获取验证码图片 * * @return 验证码图片 */
        public BufferedImage getImage() { 
            return this.image;
        }
    
        /** * 获取验证码 * * @return 验证码 */
        public String getVerificationCode() { 
            return this.verificationCode;
        }
    
        private void init() { 
            // 在内存中创建验证码图片
            BufferedImage bufferedImage = new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
            // 获取图形上下文
            Graphics2D graphics = bufferedImage.createGraphics();
            try { 
                // 随机数生成器类
                Random random = new Random();
                // 图像背景设置为白色
                graphics.setColor(Color.white);
                graphics.fillRect(0, 0, WIDTH, HEIGHT);
                // 创建字体，字体的大小应该根据图片的高度来定
                Font font = new Font("Fixedsys", Font.PLAIN, HEIGHT - 2);
                // 设置字体
                graphics.setFont(font);
                // 画边框
                graphics.setColor(Color.BLACK);
                graphics.drawRect(0, 0, WIDTH - 1, HEIGHT - 1);
                // 随机产生160条干扰线，使图象中的认证码不易被其它程序探测到
                for (int i = 0; i < INTERFERING_LINE_COUNT; i++) { 
                    // 每条干扰线都设置为随机颜色
                    graphics.setColor(getRandomColor());
                    int x2 = random.nextInt(WIDTH);
                    int y2 = random.nextInt(HEIGHT);
                    int x1 = random.nextInt(WIDTH);
                    int y1 = random.nextInt(HEIGHT);
                    graphics.drawLine(x2, y2, x2 + x1, y2 + y1);
                }
    
                // randomCode用于保存随机产生的验证码，以便用户登录后进行验证
                StringBuilder randomCode = new StringBuilder();
                int x = WIDTH / (CODE_COUNT + 1);
                int codeY = HEIGHT - 4;
                // 随机产生 codeCount 数字的验证码
                for (int i = 0; i < CODE_COUNT; i++) { 
                    // 获取随机产生的验证码数字
                    String strRand = String.valueOf(codeSequence[random.nextInt(10)]);
                    // 用随机产生的颜色将验证码绘制到图像中
                    graphics.setColor(getRandomColor());
                    graphics.drawString(strRand, (i + 1) * x, codeY);
                    // 将产生的四个随机数组合在一起
                    randomCode.append(strRand);
                }
    
                // 赋值验证码
                this.verificationCode = String.valueOf(randomCode);
                // 赋值图像
                this.image = bufferedImage;
            } finally { 
                // 不关闭的话有OOM风险
                graphics.dispose();
            }
        }
    
        /** * 生成随机颜色 * @return 随机颜色 */
        private static Color getRandomColor() { 
            Random random = new Random();
            return new Color(random.nextInt(256), random.nextInt(256), random.nextInt(256));
        }
    
    }

## 2. Controller层 ##

package com.jbp.controller;
    
    import com.jbp.util.OptimizeVerificationCodeUtil;
    import com.jbp.util.VerificationCodeUtil;
    
    
    import lombok.extern.slf4j.Slf4j;
    import org.apache.commons.lang.StringUtils;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RestController;
    
    import javax.imageio.ImageIO;
    import javax.servlet.ServletOutputStream;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    import java.awt.image.BufferedImage;
    import java.io.IOException;
    import java.util.Map;
    
    
    /** * @ClassName: VerificationCodeController * @description: 验证码Controller * @author: JiangBeiPing * @create: 2021-05-11 11:28 * @Version: 1.0 **/
    @RequestMapping("/verification")
    @RestController
    @Slf4j
    public class VerificationCodeController { 
    
        @RequestMapping(value = "/getSecurityCode", produces = { "application/json;charset=UTF-8"},method = RequestMethod.GET)
        public void getSecurityCode(HttpServletResponse response, HttpServletRequest request){ 
            // 通知浏览器不要缓存
            response.setHeader("Expires","-1");
            response.setHeader("Cache-Control", "no-cache");
            response.setHeader("Pragma", "-1");
            // 将验证码输入到session中，用来验证
            OptimizeVerificationCodeUtil optimizeVerificationCodeUtil = OptimizeVerificationCodeUtil.instance();
            String verificationCode = optimizeVerificationCodeUtil.getVerificationCode();
            request.getSession().setAttribute(OptimizeVerificationCodeUtil.SESSION_VERIFICATION_CODE,verificationCode);
            try { 
                ImageIO.write(optimizeVerificationCodeUtil.getImage(), "jpg", response.getOutputStream());
            } catch (IOException e) { 
                e.printStackTrace();
            }
        }
    
    }

## 3. 效果测试 ##

ps：无视水印，问就是在划水  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3h1ZWd1Y2hlbg_size_16_color_FFFFFF_t_70]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3h1ZWd1Y2hlbg_size_16_color_FFFFFF_t_70]: /images/20221021/c615fbdcd0be40b9bc0df735b9afacb9.png