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This article mainly explains "how to realize the function module of springboot picture CAPTCHA". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Next let the editor to take you to learn "springboot picture verification code function module how to achieve" it!

The specific effects are as follows:

Step 1: tool class

This tool class is the core of generating CAPTCHA images, which can be copied directly to the project without modification. All personalized parameters, such as font size, background color, number of interference lines, height and width, can be set according to your own needs, such as API provided externally.

Almost every line of the code is annotated in detail; if you encounter special personalized needs, you can adjust this tool class.

Package com.feng.util;/** * @ return null * @ author Ladidol * @ description * @ date 2022-4-11 22:15 * / import java.awt.*;import java.awt.geom.AffineTransform;import java.awt.image.BufferedImage;import java.util.Random / * graphic CAPTCHA generation * / public class VerifyUtil {/ / default CAPTCHA character set private static final char [] chars = {'0,1,' 2, 3, 4, 5, 6, 7, 8, 9, 9, 9, 9, 9, 6, 6, 7, 8, 9, a, b, c, d, e' 'fags,' gathers, 'hacks,' iFors, 'jacks,' kunks, 'lags,' masks, 'nails,' oaths, 'packs,' Q-bands, 'rashes,' slots, 'tweets,' uprights, 'vaults,' winters,'x-rays, 'yudes,' zones, 'Aids,' breads, 'cations,' D' 'Eise, 'Flying,' Globe, 'Hatch,' Idle, 'Jake,' Knight, 'Little,' Malley, 'Night,' Oval, 'Pure,' Qhammer, 'Rain,' Steam, 'Turing,' Utility, 'Venture,' Waring, 'Xerox,' Yoyama,'Z'} / / default number of characters private final Integer SIZE; / / default number of interference lines private final int LINES; / / default width private final int WIDTH; / / default height private final int HEIGHT; / / default font size private final int FONT_SIZE; / / default font skew private final boolean TILT; private final Color BACKGROUND_COLOR / * * initialize the basic parameters * * @ param builder * / private VerifyUtil (Builder builder) {SIZE = builder.size; LINES = builder.lines; WIDTH = builder.width; HEIGHT = builder.height; FONT_SIZE = builder.fontSize; TILT = builder.tilt; BACKGROUND_COLOR = builder.backgroundColor } / * instantiate constructor object * * @ return * / public static Builder newBuilder () {return newBuilder ();} / * @ return generate random CAPTCHA and picture * Object [0]: CAPTCHA string * Object [1]: CAPTCHA image. * / public Object [] createImage () {StringBuffer sb = new StringBuffer (); / / create blank image BufferedImage image = new BufferedImage (WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB); / / get picture brush Graphics2D graphic = image.createGraphics (); / / set anti-aliasing graphic.setRenderingHint (RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON) / / set brush color graphic.setColor (BACKGROUND_COLOR); / / draw rectangular background graphic.fillRect (0,0, WIDTH, HEIGHT); / / draw random characters Random ran = new Random (); / / graphic.setBackground (Color.WHITE) / / calculate the width of each character, where one character is reserved for the left and right margins int codeWidth = WIDTH / (SIZE + 1); the coordinates of the y axis of the / / character are int y = HEIGHT * 3 / 4; for (int I = 0; I)

< SIZE; i++) { // 设置随机颜色 graphic.setColor(getRandomColor()); // 初始化字体 Font font = new Font(null, Font.BOLD + Font.ITALIC, FONT_SIZE); if (TILT) { // 随机一个倾斜的角度 -45到45度之间 int theta = ran.nextInt(45); // 随机一个倾斜方向 左或者右 theta = (ran.nextBoolean() == true) ? theta : -theta; AffineTransform affineTransform = new AffineTransform(); affineTransform.rotate(Math.toRadians(theta), 0, 0); font = font.deriveFont(affineTransform); } // 设置字体大小 graphic.setFont(font); // 计算当前字符绘制的X轴坐标 int x = (i * codeWidth) + (codeWidth / 2); // 取随机字符索引 int n = ran.nextInt(chars.length); // 得到字符文本 String code = String.valueOf(chars[n]); // 画字符 graphic.drawString(code, x, y); // 记录字符 sb.append(code); } // 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)); } // 返回验证码和图片 return new Object[]{sb.toString(), image}; } /** * 随机取色 */ private Color getRandomColor() { Random ran = new Random(); Color color = new Color(ran.nextInt(256), ran.nextInt(256), ran.nextInt(256)); return color; } /** * 构造器对象 */ public static class Builder { // 默认字符数量 private int size = 4; // 默认干扰线数量 private int lines = 10; // 默认宽度 private int width = 80; // 默认高度 private int height = 35; // 默认字体大小 private int fontSize = 25; // 默认字体倾斜 private boolean tilt = true; //背景颜色 private Color backgroundColor = Color.LIGHT_GRAY; public Builder setSize(int size) { this.size = size; return this; } public Builder setLines(int lines) { this.lines = lines; return this; } public Builder setWidth(int width) { this.width = width; return this; } public Builder setHeight(int height) { this.height = height; return this; } public Builder setFontSize(int fontSize) { this.fontSize = fontSize; return this; } public Builder setTilt(boolean tilt) { this.tilt = tilt; return this; } public Builder setBackgroundColor(Color backgroundColor) { this.backgroundColor = backgroundColor; return this; } public VerifyUtil build() { return new VerifyUtil(this); } }}第二步：图片生成: 使用默认参数: //生成图片验证码Object[] verify = VerifyUtil.newBuilder().build().createImage(); 自定义参数生成: // 这个根据自己的需要设置对应的参数来实现个性化// 返回的数组第一个参数是生成的验证码，第二个参数是生成的图片Object[] objs = VerifyUtil.newBuilder() .setWidth(120) //设置图片的宽度 .setHeight(35) //设置图片的高度 .setSize(6) //设置字符的个数 .setLines(10) //设置干扰线的条数 .setFontSize(25) //设置字体的大小 .setTilt(true) //设置是否需要倾斜 .setBackgroundColor(Color.WHITE) //设置验证码的背景颜色 .build() //构建VerifyUtil项目 .createImage(); //生成图片整合到springboot项目中: 需要引入的maven依赖: org.springframework.boot spring-boot-starter-data-redis org.apache.commons commons-pool2 net.jodah expiringmap 0.5.10 获取相关的验证码: service层: package com.feng.service;import org.cuit.epoch.result.Result;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;/** * @return null * @author Ladidol * @description * @date 2022/4/11 22:15 */public interface VerifyService { /** * 创建图片验证码 * @param response * @param request * @throws IOException */ void createCode(HttpServletResponse response, HttpServletRequest request) throws IOException; /** * 检查图片验证码 * @param * @param * @throws IOException */ Result checkCode(String verificationCode);} serviceimpl层: package com.feng.service.impl;import com.feng.service.VerifyService;import com.feng.util.RedisServiceImpl;import com.google.common.net.HttpHeaders;import com.feng.util.VerifyUtil;import org.springframework.http.ResponseCookie;import org.springframework.stereotype.Service;import javax.annotation.Resource;import javax.imageio.ImageIO;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.io.OutputStream;import java.time.Duration;/** * @return null * @author Ladidol * @description * @date 2022/4/11 22:15 */@Servicepublic class VerifyServiceImpl implements VerifyService { @Resource RedisServiceImpl redisUtil; /** * 生成图片验证码 * @param response * @param request * @throws IOException */ @Override public void createCode(HttpServletResponse response, HttpServletRequest request) throws IOException { //获取session HttpSession session = request.getSession(); //获得sessionId String id = session.getId(); System.out.println(); ResponseCookie cookie = ResponseCookie.from("JSESSIONID",id) .secure(true) .domain("") .path("/") .maxAge(Duration.ofHours(1)) .sameSite("None") .build(); //清除之前缓存的图片验证码 if (!String.valueOf(request.getSession().getAttribute("SESSION_VERIFY_CODE_"+id)).isEmpty()){ String getVerify = String.valueOf(request.getSession().getAttribute("SESSION_VERIFY_CODE_"+id)); redisUtil.del(getVerify); System.out.println("清除成功"); } //生成图片验证码,用的默认参数 Object[] verify = VerifyUtil.newBuilder().build().createImage(); //将验证码存入session session.setAttribute("SESSION_VERIFY_CODE_" + id, verify[0]); //打印验证码 System.out.println(verify[0]); //将验证码存入redis redisUtil.set((String) verify[0],id,5*60); //将图片传给浏览器 BufferedImage image = (BufferedImage) verify[1]; response.setContentType("image/png"); response.setHeader(HttpHeaders.SET_COOKIE,cookie.toString()); OutputStream ops = response.getOutputStream(); ImageIO.write(image,"png",ops); } @Override public Result checkCode(String verificationCode){ if (!redisUtil.hasKey(verificationCode)){ return new Result(false,"验证码错误"); } redisUtil.del(verificationCode); return R.success(); }} 这里面还会用到redis相关的工具类,我就不列出来了,想要的话可以看我以前的博客工具类戳这里 controller层: 这里有用到@RequiredArgsConstructor, 就是简单的注入而已, 如果想要详细了解戳这里 package com.feng.controller;import lombok.RequiredArgsConstructor;import com.feng.annotation.LimitRequest;import com.feng.service.VerifyService;import org.springframework.web.bind.annotation.*;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;/** * @return null * @author Ladidol * @description 这里主要就是多种验证码和登录相关的东西 * @date 2022/4/11 21:46 */@RestController@RequestMapping("/verify")@RequiredArgsConstructor//这是在lombok工具给的注入方式,真帅public class VerifyController { private final VerifyService verifyService; /** * 获取图片验证码 */ @LimitRequest(count = 5)//这个注解就是表示, 你在限制时间里(我们这里默认是六秒钟), 只能请求五次 @GetMapping("/getCode") public void getCode(HttpServletResponse response, HttpServletRequest request) throws IOException { verifyService.createCode(response, request); } @LimitRequest(count = 5)//这个注解就是表示, 你在限制时间里(我们这里默认是六秒钟), 只能请求五次 @GetMapping("/checkCode") public Result checkCode(String code){ return verifyService.checkCode(code); }} 这里为了不被一直无限制的访问该服务, 我们用了一个限制ip访问次数的注解@LimitRequest annotion包下的注解类: package com.feng.annotation;import java.lang.annotation.*;/** * @return null * @author Ladidol * @description 限制ip访问次数注解 * @date 2022/4/11 22:15 */@Documented@Target(ElementType.METHOD) // 说明该注解只能放在方法上面@Retention(RetentionPolicy.RUNTIME)public @interface LimitRequest { long time() default 6000; // 限制时间 单位：毫秒 int count() default 3; // 允许请求的次数} aspect包下的切面类: package com.feng.aspect;import net.jodah.expiringmap.ExpirationPolicy;import net.jodah.expiringmap.ExpiringMap;import org.aspectj.lang.ProceedingJoinPoint;import org.aspectj.lang.annotation.Around;import org.aspectj.lang.annotation.Aspect;import org.aspectj.lang.annotation.Pointcut;import com.feng.annotation.LimitRequest;import org.cuit.epoch.exception.AppException;import org.springframework.stereotype.Component;import org.springframework.web.context.request.RequestAttributes;import org.springframework.web.context.request.RequestContextHolder;import org.springframework.web.context.request.ServletRequestAttributes;import javax.servlet.http.HttpServletRequest;import java.util.concurrent.ConcurrentHashMap;import java.util.concurrent.TimeUnit;/** * @return null * @author Ladidol * @description * @date 2022/4/11 22:15 */@Aspect@Componentpublic class LimitRequestAspect { private static ConcurrentHashMap book = new ConcurrentHashMap(); // 定义切点 // 让所有有@LimitRequest注解的方法都执行切面方法 @Pointcut("@annotation(limitRequest)") public void excudeService(LimitRequest limitRequest) { } @Around("excudeService(limitRequest)") public Object doAround(ProceedingJoinPoint pjp, LimitRequest limitRequest) throws Throwable { // 获得request对象 RequestAttributes ra = RequestContextHolder.getRequestAttributes(); ServletRequestAttributes sra = (ServletRequestAttributes) ra; HttpServletRequest request = sra.getRequest(); // 获取Map对象， 如果没有则返回默认值 // 第一个参数是key， 第二个参数是默认值 ExpiringMap uc = book.getOrDefault(request.getRequestURI(), ExpiringMap.builder().variableExpiration().build()); Integer uCount = uc.getOrDefault(request.getRemoteAddr(), 0); if (uCount >

= limitRequest.count () {/ / exceeds the number of times, does not execute the target method System.out.println ("API request exceeds the number of times!"); throw new AppException ("the number of interface requests exceeds the number of times!") } else if (uCount = = 0) {/ / when the first request is made, set valid time / / uc.put (request.getRemoteAddr (), uCount + 1, ExpirationPolicy.CREATED, limitRequest.time (), TimeUnit.MILLISECONDS);} else {/ / does not exceed the number of times, record plus a uc.put (request.getRemoteAddr (), uCount + 1) } book.put (request.getRequestURI (), uc); / / the value of result is the return value of the intercepted method Object result = pjp.proceed (); return result;}}

In order to catch the global exception throw and conform to the restful specification, we add this handling class:

The global exception class under the handle package:

Package org.cuit.epoch.handler;import lombok.extern.log4j.Log4j2;import org.cuit.epoch.exception.AppException;import org.cuit.epoch.result.R;import org.cuit.epoch.result.Result;import org.springframework.web.bind.annotation.ControllerAdvice;import org.springframework.web.bind.annotation.ExceptionHandler;import org.springframework.web.bind.annotation.ResponseBody ControllerAdvice@Log4j2public class GlobalExceptionHandler {@ ExceptionHandler (Exception.class) @ ResponseBody public Result error (Exception e) {log.error (e.getMessage ()); e.printStackTrace (); return R.fail (e.getMessage ());} @ ExceptionHandler (AppException.class) @ ResponseBody public Result error (AppException e) {log.error (e.getMessage ()); e.printStackTrace () Return R.fail (e.getMessage ());}}

Application.yaml file:

Spring: cache: type: redis redis: # redis connection configuration host: ip address of your own redis port: redis port password: password jedis: pool: max-active: 8 max-wait:-1ms max-idle: 500 min-idle: 0 lettuce: shutdown-timeout: 0ms

The final project structure is as follows:

First get a CAPTCHA:

Verify that it was successful:

Successful results:

Verification failed result:

An error may be reported when the number of requests within a specified period of time exceeds the specified number:

At this point, I believe that everyone on the "springboot picture CAPTCHA function module how to achieve" have a deeper understanding, might as well to the actual operation of it! Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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