java生成前端验证码+验证「kaptcha」
1、前言
kaptcha是一个非常实用的短信验证码生成工具，通过简单配置即可实现多样化的验证码。
2、引入依赖
<!--第三方验证码-->
<dependency>
<groupId>com.github.penggle</groupId>
<artifactId>kaptcha</artifactId>
<version>2.3.2</version>
</dependency>
3、前台
假设前台调用样式如下：
<img alt="验证码" width="128" height="42" @click="changeImage" src="项目地址/validate/captcha-image" ref="checkCode"/>
通过调用 /validate/captcha-image 接口地址获取验证码。
4、后台
4.1 controller
@RequestMapping("/captcha-image")
public void defaultKaptcha(HttpServletRequest httpServletRequest,HttpServletResponse httpServletResponse) throws Exception{
validateService.defaultKaptcha(httpServletRequest,httpServletResponse);
}
4.2 serviceImpl
@Autowired
private StringRedisTemplate redisTemplate;
@Autowired
DefaultKaptcha defaultKaptcha;
/*验证码失效时间 15分钟*/
private static final int VALID_CODE_CACHE_EXPIRE_TIME = 900;
/**
* 生成图片验证码
* @param httpServletRequest request
* @param httpServletResponse response
*/
public void defaultKaptcha(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse)throws Exception{
byte[] captchaChallengeAsJpeg = null;
ByteArrayOutputStream jpegOutputStream = new ByteArrayOutputStream();
try {
/*生产验证码字符串并保存到session中*/
String createText = defaultKaptcha.createText();
String key = String.format("login_valid_code_%s", httpServletRequest.getSession().getId());
redisTemplate.opsForValue().set(key, createText, VALID_CODE_CACHE_EXPIRE_TIME, TimeUnit.SECONDS);
/*httpServletRequest.getSession().setAttribute("vrifyCode", createText);*/
/*使用生产的验证码字符串返回一个BufferedImage对象并转为byte写入到byte数组中*/
BufferedImage challenge = defaultKaptcha.createImage(createText);
ImageIO.write(challenge, "jpg", jpegOutputStream);
} catch (IllegalArgumentException e) {
httpServletResponse.sendError(HttpServletResponse.SC_NOT_FOUND);
return;
}
/*定义response输出类型为image/jpeg类型，使用response输出流输出图片的byte数组*/
captchaChallengeAsJpeg = jpegOutputStream.toByteArray();
httpServletResponse.setHeader("Cache-Control", "no-store");
httpServletResponse.setHeader("Pragma", "no-cache");
httpServletResponse.setDateHeader("Expires", 0);
httpServletResponse.setContentType("image/jpeg");
ServletOutputStream responseOutputStream =
httpServletResponse.getOutputStream();
responseOutputStream.write(captchaChallengeAsJpeg);
responseOutputStream.flush();
responseOutputStream.close();
}
补充：DefaultKaptcha是引入kaptcha依赖后即直接可引入的;
如上思路代码已经很清晰了，通过DefaultKaptcha创建验证码文本，然后存入redis一份，用于后面的验证使用；
注意：redis 拼接的 key 规则为 login_valid_code_ + sessionId（session id）
5、效果
前端实际应用效果:
浏览器直接调用接口效果:
6、验证
6.1 controller
从redis中取
/**
* 验证验证码
* @return Object
*/
@UnAuthorization
@RequestMapping(value = "code/check", method = {RequestMethod.POST})
public Object checkCode(@RequestBody @Valid CheckValidateRequest checkValidateRequest , BindingResult bindingResult, HttpServletRequest request) {
return validateService.checkValidateCode(httpServletRequest.getSession().getId(),checkValidateRequest.getValidCode());
}
6.2 serviceImpl
/**
* 验证短信验证码有效性
* @param mobile 手机号码 或者 sessionId
* @param validCode 验证码
* @return boolean
*/
public boolean checkValidateCode(String sessionId, String validCode) {
Object iValidCodeFromRedis = cacheService.getCache(String.format("login_valid_code_%s", sessionId));
String sValidCodeFromRedis = String.valueOf(iValidCodeFromRedis);
if (StringUtils.isNotBlank(sValidCodeFromRedis) && validCode.equalsIgnoreCase(sValidCodeFromRedis)) {
return true;
}
throw new CommonException(ValidateStatusEn.CHECK_VALID_CODE_FAILED.getErrorMsg(), ValidateStatusEn.CHECK_VALID_CODE_FAILED.getErrorCode());
}
补充：通过 login_valid_code_ + sessionId 从 redis 中获取验证码进行校验。
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