spring框架实现滑动验证码功能

1. 整体描述

之前项目需要在验证码模块，增加滑动验证码，用来给手机端使用的，大概看了下，主要方法就是将图片切割，然后记住偏移量，进行滑动，前端验证的时候，需要用前端传入的偏移量和生成的偏移量进行对比，如果在阈值之内，就验证通过，否则就不通过。具体实现方式见下文。之前没时间写，最近记录一下。

2. 具体实现

本工程主要依赖springboot框架，并且需要redis存验证码的信息，还需要几个图片，用来生成验证码。

2.1 滑动验证码实体类

package com.thcb.captchademo.captcha.domain;import lombok.Data;/*** 滑动验证码** @author thcb* @date 2023-05-25*/@Data
public class Captcha {/*** 随机字符串**/private String nonceStr;/*** 验证值**/private String value;/*** 生成的画布的base64**/private String canvasSrc;/*** 画布宽度**/private Integer canvasWidth;/*** 画布高度**/private Integer canvasHeight;/*** 生成的阻塞块的base64**/private String blockSrc;/*** 阻塞块宽度**/private Integer blockWidth;/*** 阻塞块高度**/private Integer blockHeight;/*** 阻塞块凸凹半径**/private Integer blockRadius;/*** 阻塞块的横轴坐标**/private Integer blockX;/*** 阻塞块的纵轴坐标**/private Integer blockY;/*** 图片获取位置**/private Integer place;
}

2.2 滑动验证码登录VO

package com.thcb.captchademo.captcha.domain;import lombok.Data;/*** 滑动验证码登录Vo** @author thcb* @date 2023-05-25*/@Data
public class LoginVo {/*** 随机字符串**/private String nonceStr;/*** 验证值**/private String value;
}

2.3 滑动验证码接口返回类

package com.thcb.captchademo.captcha.utils;import java.util.HashMap;/*** 操作消息提醒** @author thcb*/
public class AjaxResult extends HashMap<String, Object> {private static final long serialVersionUID = 1L;/*** 状态码*/public static final String CODE_TAG = "code";/*** 返回内容*/public static final String MSG_TAG = "msg";/*** 数据对象*/public static final String DATA_TAG = "data";/*** 初始化一个新创建的 AjaxResult 对象，使其表示一个空消息。*/public AjaxResult() {}/*** 初始化一个新创建的 AjaxResult 对象** @param code 状态码* @param msg  返回内容*/public AjaxResult(int code, String msg) {super.put(CODE_TAG, code);super.put(MSG_TAG, msg);}/*** 初始化一个新创建的 AjaxResult 对象** @param code 状态码* @param msg  返回内容* @param data 数据对象*/public AjaxResult(int code, String msg, Object data) {super.put(CODE_TAG, code);super.put(MSG_TAG, msg);if (data != null && !data.equals("")) {super.put(DATA_TAG, data);}}/*** 返回成功消息** @return 成功消息*/public static AjaxResult success() {return AjaxResult.success("操作成功");}/*** 返回成功数据** @return 成功消息*/public static AjaxResult success(Object data) {return AjaxResult.success("操作成功", data);}/*** 返回成功消息** @param msg 返回内容* @return 成功消息*/public static AjaxResult success(String msg) {return AjaxResult.success(msg, null);}/*** 返回成功消息** @param msg  返回内容* @param data 数据对象* @return 成功消息*/public static AjaxResult success(String msg, Object data) {return new AjaxResult(200, msg, data);}/*** 返回错误消息** @return*/public static AjaxResult error() {return AjaxResult.error("操作失败");}/*** 返回错误消息** @param msg 返回内容* @return 警告消息*/public static AjaxResult error(String msg) {return AjaxResult.error(msg, null);}/*** 返回错误消息** @param msg  返回内容* @param data 数据对象* @return 警告消息*/public static AjaxResult error(String msg, Object data) {return new AjaxResult(500, msg, data);}/*** 返回错误消息** @param code 状态码* @param msg  返回内容* @return 警告消息*/public static AjaxResult error(int code, String msg) {return new AjaxResult(code, msg, null);}
}

2.4 滑动验证码工具类

此类是核心类，主要实现了图片的切割功能。

package com.thcb.captchademo.captcha.utils;import com.thcb.captchademo.captcha.domain.Captcha;import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.Base64;
import java.util.Objects;
import java.util.Random;/*** 滑动验证码工具类** @author thcb* @date 2023-05-25*/
public class CaptchaUtils {/*** 网络图片地址**/private final static String IMG_URL = "https://loyer.wang/view/ftp/wallpaper/%s.jpg";/*** 本地图片地址**/private final static String IMG_PATH = "E:\\caphcha\\%s.jpg";/*** 入参校验设置默认值**/public static void checkCaptcha(Captcha captcha) {//设置画布宽度默认值if (captcha.getCanvasWidth() == null) {captcha.setCanvasWidth(320);}//设置画布高度默认值if (captcha.getCanvasHeight() == null) {captcha.setCanvasHeight(155);}//设置阻塞块宽度默认值if (captcha.getBlockWidth() == null) {captcha.setBlockWidth(65);}//设置阻塞块高度默认值if (captcha.getBlockHeight() == null) {captcha.setBlockHeight(55);}//设置阻塞块凹凸半径默认值if (captcha.getBlockRadius() == null) {captcha.setBlockRadius(9);}//设置图片来源默认值if (captcha.getPlace() == null) {captcha.setPlace(1);}}/*** 获取指定范围内的随机数**/public static int getNonceByRange(int start, int end) {Random random = new Random();return random.nextInt(end - start + 1) + start;}/*** 获取验证码资源图**/public static BufferedImage getBufferedImage(Integer place) {try {//随机图片//获取网络资源图片if (0 == place) {int nonce = getNonceByRange(0, 1000);String imgUrl = String.format(IMG_URL, nonce);URL url = new URL(imgUrl);return ImageIO.read(url.openStream());}//获取本地图片else {int nonce = getNonceByRange(0, 20);String imgPath = String.format(IMG_PATH, nonce);File file = new File(imgPath);return ImageIO.read(file);}} catch (Exception e) {System.out.println("获取拼图资源失败");//异常处理return null;}}/*** 调整图片大小**/public static BufferedImage imageResize(BufferedImage bufferedImage, int width, int height) {Image image = bufferedImage.getScaledInstance(width, height, Image.SCALE_SMOOTH);BufferedImage resultImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);Graphics2D graphics2D = resultImage.createGraphics();graphics2D.drawImage(image, 0, 0, null);graphics2D.dispose();return resultImage;}/*** 抠图，并生成阻塞块**/public static void cutByTemplate(BufferedImage canvasImage, BufferedImage blockImage, int blockWidth, int blockHeight, int blockRadius, int blockX, int blockY) {BufferedImage waterImage = new BufferedImage(blockWidth, blockHeight, BufferedImage.TYPE_4BYTE_ABGR);//阻塞块的轮廓图int[][] blockData = getBlockData(blockWidth, blockHeight, blockRadius);//创建阻塞块具体形状for (int i = 0; i < blockWidth; i++) {for (int j = 0; j < blockHeight; j++) {try {//原图中对应位置变色处理if (blockData[i][j] == 1) {//背景设置为黑色waterImage.setRGB(i, j, Color.BLACK.getRGB());blockImage.setRGB(i, j, canvasImage.getRGB(blockX + i, blockY + j));//轮廓设置为白色，取带像素和无像素的界点，判断该点是不是临界轮廓点if (blockData[i + 1][j] == 0 || blockData[i][j + 1] == 0 || blockData[i - 1][j] == 0 || blockData[i][j - 1] == 0) {blockImage.setRGB(i, j, Color.WHITE.getRGB());waterImage.setRGB(i, j, Color.WHITE.getRGB());}}//这里把背景设为透明else {blockImage.setRGB(i, j, Color.TRANSLUCENT);waterImage.setRGB(i, j, Color.TRANSLUCENT);}} catch (ArrayIndexOutOfBoundsException e) {//防止数组下标越界异常}}}//在画布上添加阻塞块水印addBlockWatermark(canvasImage, waterImage, blockX, blockY);}/*** 构建拼图轮廓轨迹**/private static int[][] getBlockData(int blockWidth, int blockHeight, int blockRadius) {int[][] data = new int[blockWidth][blockHeight];double po = Math.pow(blockRadius, 2);//随机生成两个圆的坐标，在4个方向上 随机找到2个方向添加凸/凹//凸/凹1Random random1 = new Random();int face1 = random1.nextInt(4);//凸/凹2int face2;//保证两个凸/凹不在同一位置do {Random random2 = new Random();face2 = random2.nextInt(4);} while (face1 == face2);//获取凸/凹起位置坐标int[] circle1 = getCircleCoords(face1, blockWidth, blockHeight, blockRadius);int[] circle2 = getCircleCoords(face2, blockWidth, blockHeight, blockRadius);//随机凸/凹类型int shape = getNonceByRange(0, 1);//圆的标准方程 (x-a)²+(y-b)²=r²,标识圆心（a,b）,半径为r的圆//计算需要的小图轮廓，用二维数组来表示，二维数组有两张值，0和1，其中0表示没有颜色，1有颜色for (int i = 0; i < blockWidth; i++) {for (int j = 0; j < blockHeight; j++) {data[i][j] = 0;//创建中间的方形区域if ((i >= blockRadius && i <= blockWidth - blockRadius && j >= blockRadius && j <= blockHeight - blockRadius)) {data[i][j] = 1;}double d1 = Math.pow(i - Objects.requireNonNull(circle1)[0], 2) + Math.pow(j - circle1[1], 2);double d2 = Math.pow(i - Objects.requireNonNull(circle2)[0], 2) + Math.pow(j - circle2[1], 2);//创建两个凸/凹if (d1 <= po || d2 <= po) {data[i][j] = shape;}}}return data;}/*** 根据朝向获取圆心坐标*/private static int[] getCircleCoords(int face, int blockWidth, int blockHeight, int blockRadius) {//上if (0 == face) {return new int[]{blockWidth / 2 - 1, blockRadius};}//左else if (1 == face) {return new int[]{blockRadius, blockHeight / 2 - 1};}//下else if (2 == face) {return new int[]{blockWidth / 2 - 1, blockHeight - blockRadius - 1};}//右else if (3 == face) {return new int[]{blockWidth - blockRadius - 1, blockHeight / 2 - 1};}return null;}/*** 在画布上添加阻塞块水印*/private static void addBlockWatermark(BufferedImage canvasImage, BufferedImage blockImage, int x, int y) {Graphics2D graphics2D = canvasImage.createGraphics();graphics2D.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, 0.8f));graphics2D.drawImage(blockImage, x, y, null);graphics2D.dispose();}/*** BufferedImage转BASE64*/public static String toBase64(BufferedImage bufferedImage, String type) {try {ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();ImageIO.write(bufferedImage, type, byteArrayOutputStream);String base64 = Base64.getEncoder().encodeToString(byteArrayOutputStream.toByteArray());return String.format("data:image/%s;base64,%s", type, base64);} catch (IOException e) {System.out.println("图片资源转换BASE64失败");//异常处理return null;}}
}

2.5 滑动验证码Service

service层，，封装了工具类的一些方法，这里为了简单没写接口，正常应该是service和impl两个类。

package com.thcb.captchademo.captcha.service;import com.thcb.captchademo.captcha.domain.Captcha;
import com.thcb.captchademo.captcha.utils.CaptchaUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.ValueOperations;
import org.springframework.stereotype.Service;import java.awt.image.BufferedImage;
import java.util.UUID;
import java.util.concurrent.TimeUnit;/*** 滑动验证码Service** @author thcb* @date 2023-05-25*/@Service
public class CaptchaService {/*** 拼图验证码允许偏差**/private static Integer ALLOW_DEVIATION = 3;@Autowiredprivate StringRedisTemplate stringRedisTemplate;/*** 校验验证码** @param imageKey* @param imageCode* @return boolean**/public String checkImageCode(String imageKey, String imageCode) {ValueOperations<String, String> ops = stringRedisTemplate.opsForValue();String key = "imageCode:" + imageKey;String text = ops.get(key);if (text == null || text.equals("")) {return "验证码已失效";}// 根据移动距离判断验证是否成功if (Math.abs(Integer.parseInt(text) - Integer.parseInt(imageCode)) > ALLOW_DEVIATION) {return "验证失败，请控制拼图对齐缺口";}// 验证成功，删除redis缓存stringRedisTemplate.delete(key);return null;}/*** 缓存验证码，有效期1分钟** @param key* @param code**/public void saveImageCode(String key, String code) {ValueOperations<String, String> ops = stringRedisTemplate.opsForValue();ops.set("imageCode:" + key, code, 60, TimeUnit.SECONDS);}/*** 获取验证码拼图（生成的抠图和带抠图阴影的大图及抠图坐标）**/public Object getCaptcha(Captcha captcha) {//参数校验CaptchaUtils.checkCaptcha(captcha);//获取画布的宽高int canvasWidth = captcha.getCanvasWidth();int canvasHeight = captcha.getCanvasHeight();//获取阻塞块的宽高/半径int blockWidth = captcha.getBlockWidth();int blockHeight = captcha.getBlockHeight();int blockRadius = captcha.getBlockRadius();//获取资源图BufferedImage canvasImage = CaptchaUtils.getBufferedImage(captcha.getPlace());//调整原图到指定大小canvasImage = CaptchaUtils.imageResize(canvasImage, canvasWidth, canvasHeight);//随机生成阻塞块坐标int blockX = CaptchaUtils.getNonceByRange(blockWidth, canvasWidth - blockWidth - 10);int blockY = CaptchaUtils.getNonceByRange(10, canvasHeight - blockHeight + 1);//阻塞块BufferedImage blockImage = new BufferedImage(blockWidth, blockHeight, BufferedImage.TYPE_4BYTE_ABGR);//新建的图像根据轮廓图颜色赋值，源图生成遮罩CaptchaUtils.cutByTemplate(canvasImage, blockImage, blockWidth, blockHeight, blockRadius, blockX, blockY);// 移动横坐标String nonceStr = UUID.randomUUID().toString().replaceAll("-", "");// 缓存saveImageCode(nonceStr, String.valueOf(blockX));//设置返回参数captcha.setNonceStr(nonceStr);captcha.setBlockY(blockY);captcha.setBlockSrc(CaptchaUtils.toBase64(blockImage, "png"));captcha.setCanvasSrc(CaptchaUtils.toBase64(canvasImage, "png"));return captcha;}
}

2.6 滑动验证码Controller

controller层有两个方法，一个是获取验证码的方法，一个是验证码校验的方法。

package com.thcb.captchademo.captcha.controller;import com.thcb.captchademo.captcha.domain.Captcha;
import com.thcb.captchademo.captcha.domain.LoginVo;
import com.thcb.captchademo.captcha.service.CaptchaService;
import com.thcb.captchademo.captcha.utils.AjaxResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;/*** 滑动验证码Controller** @author thcb* @date 2023-05-25*/@RestController
@RequestMapping("/captcha")
public class CaptchaController {@Autowiredprivate CaptchaService captchaService;@PostMapping("/slideCaptchaImage")public AjaxResult getCaptcha() {return AjaxResult.success(captchaService.getCaptcha(new Captcha()));}@PostMapping(value = "/login")public AjaxResult login(@RequestBody LoginVo loginVo) {// 验证码校验String msg = captchaService.checkImageCode(loginVo.getNonceStr(), loginVo.getValue());if (msg != null && !msg.equals("")) {return AjaxResult.error(msg);}return AjaxResult.success();}}

3 工程源码

工程不算复杂，源码上传到GitCode，项目地址，上传有点问题，而且目前只能设置成私密项目，等之后可以调整的时候再改成公开的。

4 总结

滑动验证码功能不算复杂，可以和项目当前已有的验证码共存，调用不同的接口，返回不同类型的验证码，当然这个就根据项目具体情况确定了。