Easy-Captcha验证码生成以及校验（简单易懂）

说明

Java图形验证码，支持gif、中文、算术等类型，可用于Java Web、JavaSE等项目

pom引入

	<dependency><groupId>com.github.whvcse</groupId><artifactId>easy-captcha</artifactId><version>1.6.2</version></dependency>

详解参数类使用

easy-captcha 中提供了下面几种类

类名	说明	图片
ArithmeticCaptcha	数字加减乘除验证

ChineseCaptcha	中文验证

ChineseGifCaptcha	中文动态验证

GifCaptcha	动态字符验证

SpecCaptcha	字符验证

CaptchaUtil	输出类

源码说明

在上面的类中，都是继承自Captcha类，类中提供了两个主要抽象方法，自定义验证码生成器也需继承Captcha，实现下面两个方法。

   public abstract boolean out(OutputStream var1);public abstract String toBase64();

来看SpecCaptcha 默认生成验证码的工具类，其他几种验证码生成类，一样的逻辑。

//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by FernFlower decompiler)
//package com.wf.captcha;import com.wf.captcha.base.Captcha;
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import javax.imageio.ImageIO;public class SpecCaptcha extends Captcha {//空构造方法public SpecCaptcha() {}//设置验证码的长宽public SpecCaptcha(int width, int height) {this();this.setWidth(width);this.setHeight(height);}
//设置验证码的长宽，和生成验证码的长度public SpecCaptcha(int width, int height, int len) {this(width, height);this.setLen(len);}
//设置验证码的长宽，和生成验证码的长度，以及字体public SpecCaptcha(int width, int height, int len, Font font) {this(width, height, len);this.setFont(font);}// 验证码返回public boolean out(OutputStream out) {return this.graphicsImage(this.textChar(), out);}
//验证码转为base64public String toBase64() {return this.toBase64("data:image/png;base64,");}//生成验证码逻辑private boolean graphicsImage(char[] strs, OutputStream out) {try {BufferedImage bi = new BufferedImage(this.width, this.height, 1);Graphics2D g2d = (Graphics2D)bi.getGraphics();g2d.setColor(Color.WHITE);g2d.fillRect(0, 0, this.width, this.height);g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);this.drawOval(2, g2d);g2d.setStroke(new BasicStroke(2.0F, 0, 2));this.drawBesselLine(1, g2d);g2d.setFont(this.getFont());FontMetrics fontMetrics = g2d.getFontMetrics();int fW = this.width / strs.length;int fSp = (fW - (int)fontMetrics.getStringBounds("W", g2d).getWidth()) / 2;for(int i = 0; i < strs.length; ++i) {g2d.setColor(this.color());int fY = this.height - (this.height - (int)fontMetrics.getStringBounds(String.valueOf(strs[i]), g2d).getHeight() >> 1);g2d.drawString(String.valueOf(strs[i]), i * fW + fSp + 3, fY - 3);}g2d.dispose();ImageIO.write(bi, "png", out);out.flush();boolean var20 = true;return var20;} catch (IOException var18) {var18.printStackTrace();} finally {try {out.close();} catch (IOException var17) {var17.printStackTrace();}}return false;}
}

Captcha使用

以上几种提供的工具类，都有使用测试

package com.test.execption.controller;import com.ramostear.captcha.HappyCaptcha;
import com.wf.captcha.*;
import com.wf.captcha.utils.CaptchaUtil;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;/*** 类描述：EasyCaptcha 验证码工具** @author admin* @date 2023-01-02 17:47**/@RestController
@RequestMapping(value = "captcha")
public class EasyCaptchaController {/*** 生成字符串验证码** @param request* @param response* @return*/@GetMapping(value = "generatorStr")public void generator(HttpServletRequest request, HttpServletResponse response) {try {CaptchaUtil.out(request, response);} catch (IOException e) {throw new RuntimeException(e);}}/*** 生成数字验证码** @param request* @param response* @return*/@GetMapping(value = "generatorNum")public void generatorNum(HttpServletRequest request, HttpServletResponse response) {try {ArithmeticCaptcha arithmeticCaptcha = new ArithmeticCaptcha(200, 250);arithmeticCaptcha.setLen(2);CaptchaUtil.out(arithmeticCaptcha, request, response);} catch (IOException e) {throw new RuntimeException(e);}}/*** 生成中文验证码** @param request* @param response* @return*/@GetMapping(value = "generatorChinese")public void generatorChinese(HttpServletRequest request, HttpServletResponse response) {try {ChineseCaptcha chineseCaptcha = new ChineseCaptcha(200, 250);chineseCaptcha.setLen(2);CaptchaUtil.out(chineseCaptcha, request, response);} catch (IOException e) {throw new RuntimeException(e);}}/*** 生成中文动态验证码** @param request* @param response* @return*/@GetMapping(value = "generatorChineseGif")public void generatorChineseGif(HttpServletRequest request, HttpServletResponse response) {try {ChineseGifCaptcha chineseGifCaptcha = new ChineseGifCaptcha(200, 250);chineseGifCaptcha.setLen(2);CaptchaUtil.out(chineseGifCaptcha, request, response);} catch (IOException e) {throw new RuntimeException(e);}}/*** 生成字符动态验证码** @param request* @param response* @return*/@GetMapping(value = "generatorGif")public void generatorGif(HttpServletRequest request, HttpServletResponse response) {try {GifCaptcha captcha = new GifCaptcha(200, 250);captcha.setLen(2);CaptchaUtil.out(captcha, request, response);} catch (IOException e) {throw new RuntimeException(e);}}/*** 生成字符动态验证码* 这个为默认验证码生成器* @param request* @param response* @return*/@GetMapping(value = "generatorSpec")public void generatorSpec(HttpServletRequest request, HttpServletResponse response) {try {SpecCaptcha captcha = new SpecCaptcha(200, 250);captcha.setLen(2);CaptchaUtil.out(captcha, request, response);} catch (IOException e) {throw new RuntimeException(e);}}/*** 验证码校验，并且验证通过后清除，下次不允许再用** @param verifyCode* @param request* @return*/@GetMapping("/verify")public String verify(String verifyCode, HttpServletRequest request) {Boolean aBoolean = CaptchaUtil.ver(verifyCode, request);if (aBoolean) {CaptchaUtil.clear(request); //清除验证码return "通过";}return "不通过";}