1、后端功能：随机生成验证码图片，并把交给前端、接收用户输入，验证用户输入的验证码是否正确、
2、前端功能：显示验证码，提供输入框供用户输入他们看到的验证码，把用户输入的数据交给后端，接收后端返回的验证结果
后端需要完成的两个工作：1、生成验证码，2、校验验证码的正确性
接口定义：
1、生成验证码
请求url：/captcha/getCaptcha
响应：返回验证码的图片
2、校验验证码的正确性
请求url：/captcha/check
请求参数:用户输入的验证码captcha
响应：验证码正确返回true，错误返回false
index.html
展示效果：
用户点击图片之后，可以更新验证码图片
代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>验证码</title>
<style>
body {
font-family: 'Arial', sans-serif;
background-color: #f7f7f7;
margin: 0;
padding: 0;
display: flex;
justify-content: center;
align-items: center;
height: 100vh;
}
#container {
text-align: center;
background: white;
padding: 50px;
border-radius: 8px;
box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}
h1 {
color: #333;
font-size: 2em;
margin-bottom: 20px;
}
#inputCaptcha {
height: 40px;
margin-right: 10px;
vertical-align: middle;
border: 1px solid #ddd;
border-radius: 4px;
padding: 0 10px;
}
#verificationCodeImg {
vertical-align: middle;
border: 1px solid #ddd;
cursor: pointer;
transition: transform 0.2s;
}
#verificationCodeImg:hover {
transform: scale(1.05);
}
#checkCaptcha {
height: 40px;
width: 120px;
background-color: #5cb85c;
color: white;
border: none;
border-radius: 4px;
cursor: pointer;
transition: background-color 0.2s;
}
#checkCaptcha:hover {
background-color: #4cae4c;
}
</style>
</head>
<body>
<div id="container">
<h1>输入验证码</h1>
<div id="confirm">
<input type="text" name="inputCaptcha" id="inputCaptcha">
<img id="verificationCodeImg" src="http://127.0.0.1:8080/captcha/getCaptcha" style="cursor: pointer;"
title="看不清？换一张"/>
<input type="button" value="提交" id="checkCaptcha">
</div>
</div>
<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.4/jquery.min.js"></script>
<script>
$("#verificationCodeImg").click(function () {
$(this).hide().attr('src', 'http://127.0.0.1:8080/captcha/getCaptcha?dt=' + new Date().getTime()).fadeIn();
});
$("#checkCaptcha").click(function () {
$.ajax({
type: "post",
url: "captcha/check",
data: {
captcha: $("#inputCaptcha").val()
},
success: function (result) {
if (result) {
location.href = "success.html"
} else {
alert("验证码错误")
}
}
});
});
</script>
</body>
</html>
success.html，当用户验证码输入正确时展示的内容
展示效果：
代码如下：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>验证成功页</title>
<style>
body {
font-family: 'Arial', sans-serif;
background-color: #f7f7f7;
margin: 0;
padding: 0;
display: flex;
justify-content: center;
align-items: center;
height: 100vh;
}
.container {
text-align: center;
background: white;
padding: 50px;
border-radius: 8px;
box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}
h1 {
color: green;
font-size: 2.5em;
margin: 0;
}
p {
color: blue;
font-size: 1.2em;
margin-top: 20px;
}
</style>
</head>
<body>
<div class="container">
<h1>验证成功</h1>
</div>
</body>
</html>
结构如下：
在pom.xml中添加依赖：
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-captcha</artifactId>
<version>5.8.26</version>
</dependency>
CaptchaController类：
@RestController
@RequestMapping("/captcha")
public class CaptchaController {
//注入
@Autowired
private CaptchaProperties captchaProperties;
@Value("${captcha.session.key}")
private String key;
@Value("${captcha.session.datetime}")
private String datetime;
@RequestMapping("/getCaptcha")
public void getCaptcha(HttpServletResponse response, HttpSession session) throws IOException {
//定义图形验证码的长和宽
LineCaptcha lineCaptcha = CaptchaUtil.createLineCaptcha(captchaProperties.getWidth(), captchaProperties.getHeight());
String code = lineCaptcha.getCode();
//设置session,把验证码信息存储到session中
session.setAttribute(key, code);
session.setAttribute(datetime, new Date());
//验证码写入浏览器
lineCaptcha.write(response.getOutputStream());
//设置ContentType
response.setContentType("image/jpeg");
//设置编码
response.setCharacterEncoding("utf8");
//防止浏览器缓存验证码图片
response.setHeader("Pragma", "No-cache");
}
@RequestMapping("/check")
public boolean check(String captcha, HttpSession session) {
String code = (String) session.getAttribute(key);
if (!StringUtils.hasLength(captcha)) {
return false;
}
//从session中获取时间
Date date = (Date) session.getAttribute(datetime);
if (date == null || System.currentTimeMillis() - date.getTime() > 60 * 1000) {
//session为null,或者session过期(超过一分钟就算过期)
//System.currentTimeMillis() - date.getTime(): 当前时间-请求时间
return false;
}
//不区分大小写
return captcha.equalsIgnoreCase(code);
}
}
CaptchaProperties类：
@ConfigurationProperties(prefix = "captcha")
@Configuration
@Data
public class CaptchaProperties {
private Integer height;
private Integer width;
}
MySession类：
@Data
public class MySession {
private String key;
private String datetime;
}
配置文件 application.yml：
captcha:
height: 50
width: 150
session:
key: CaptchaCode
datetime: CaptchaDate