SpringBoot实现Thymeleaf验证码生成

SpringBoot实现Thymeleaf验证码生成

使用后台返回验证码图片，验证码存到session中后端实现校验，前端只展示验证码图片。

本篇用SpringBoot Thymeleaf实现验证码生成。

创建springboot项目 引入依赖

完整pom.xml

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

4.0.0

org.springframework.boot

spring-boot-starter-parent

2.2.6.RELEASE

com.example

web

0.0.1-SNAPSHOT

web

Demo project for Spring Boot

1.8

org.springframework.boot

spring-boot-starter-web

org.springframework.boot

spring-boot-starter-test

test

org.junit.vintage

junit-vintage-engine

org.springframework.boot

spring-boot-starter-thymeleaf

org.springframework.boot

spring-boot-maven-plugin

xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">

4.0.0

org.springframework.boot

spring-boot-starter-parent

2.2.6.RELEASE

com.example

web

0.0.1-SNAPSHOT

web

Demo project for Spring Boot

1.8

org.springframework.boot

spring-boot-starter-web

org.springframework.boot

spring-boot-starter-test

test

org.junit.vintage

junit-vintage-engine

org.springframework.boot

spring-boot-starter-thymeleaf

org.springframework.boot

spring-boot-maven-plugin

application.yml配置 Thymeleaf

#Thymeleaf配置

spring:

mvc:

static-path-pattern: /**

thymeleaf:

mode: HTML

encoding: UTF-8

#关闭缓存

cache: false

创建CaptchaController.java 类

package com.example.web.controller;

import com.example.web.util.VerifyCode;

import org.springframework.web.bind.annotation.RequestMapping;

import org.springframework.web.bind.annotation.RestController;

import javax.imageio.ImageIO;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import java.awt.image.BufferedImage;

import java.io.IOException;

import java.io.OutputStream;

@RestController

public class CaptchaController {

/* 获取验证码图片*/

@RequestMapping("/getVerifyCode")

public void getVerificationCode(HttpServletResponse response, HttpServletRequest request) {

try {

int width = 200;

int height = 69;

BufferedImage verifyImg = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);//生成对应宽高的初始图片

String randomText = VerifyCode.drawRandomText(width, height, verifyImg);//单独的一个类方法，出于代码复用考虑，进行了封装。功能是生成验证码字符并加上噪点，干扰线，返回值为验证码字符

request.getSession().setAttribute("verifyCode", randomText);

response.setContentType("image/png");//必须设置响应内容类型为图片，否则前台不识别

OutputStream os = response.getOutputStream(); //获取文件输出流

ImageIO.write(verifyImg, "png", os);//输出图片流

os.flush();

os.close();//关闭流

} catch (IOException e) {

e.printStackTrace();

}

}

}

创建VerifyCode.java 工具类

package com.example.web.util;

import java.awt.*;

import java.awt.image.BufferedImage;

import java.util.Random;

public class VerifyCode {

public static String drawRandomText(int width, int height, BufferedImage verifyImg) {

Graphics2D graphics = (Graphics2D) verifyImg.getGraphics();

graphics.setColor(Color.WHITE);//设置画笔颜色-验证码背景色

graphics.fillRect(0, 0, width, height);//填充背景

graphics.setFont(new Font("微软雅黑", Font.BOLD, 40));

//数字和字母的组合

String baseNumLetter = "123456789abcdefghijklmnopqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ";

StringBuilder builder = new StringBuilder();

int x = 10; //旋转原点的 x 坐标

String ch;

Random random = new Random();

for (int i = 0; i < 4; i++) {

graphics.setColor(getRandomColor());

//设置字体旋转角度

int degree = random.nextInt() % 30; //角度小于30度

int dot = random.nextInt(baseNumLetter.length());

ch = baseNumLetter.charAt(dot) + "";

builder.append(ch);

//正向旋转

graphics.rotate(degree * Math.PI / 180, x, 45);

graphics.drawString(ch, x, 45);

//反向旋转

graphics.rotate(-degree * Math.PI / 180, x, 45);

x += 48;

}

//画干扰线

for (int i = 0; i < 6; i++) {

// 设置随机颜色

graphics.setColor(getRandomColor());

// 随机画线

graphics.drawLine(random.nextInt(width), random.nextInt(height),

random.nextInt(width), random.nextInt(height));

}

//添加噪点

for (int i = 0; i < 30; i++) {

int x1 = random.nextInt(width);

int y1 = random.nextInt(height);

graphics.setColor(getRandomColor());

graphics.fillRect(x1, y1, 2, 2);

}

return builder.toString();

}

/**

* 随机取色

*/

private static Color getRandomColor() {

Random ran = new Random();

return new Color(ran.nextInt(256),

ran.nextInt(256), ran.nextInt(256));

}

}

创建UserController.java 类

package com.example.web.controller;

import org.springframework.stereotype.Controller;

import org.springframework.web.bind.annotation.RequestMapping;

@Controller

public class UserController {

@RequestMapping("/login")

public String login() {

return "login";

}

}

resources/templates目录下创建login.html

启动项目访问http://localhost:8080/login

点击图片可以更换验证码，至于后面的后台验证就不讲了。

参考文章后台java 实现验证码生成

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