Java实现随机验证码和验证码图片渲染功能-蒲公英云

0.注意事项：

图片格式（宽、高）、干扰线及数量在工具类的成员变量配置
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();
        }
    }
}