SpringMVC+kaptcha实现图形验证码

小灰灰 2022-08-10 03:38 231阅读 0赞

# 基础准备 #

## maven ##

在pom.xml中引入依赖即可。

<dependency>
            <groupId>com.github.axet</groupId>
            <artifactId>kaptcha</artifactId>
            <version>0.0.9</version>
        </dependency>

## 配置 ##

在applicationContext中写入配置

# 代码编写 #

## 后端 ##

声明一个Controller用来处理请求，并返回图片。同时将验证码存在Session中，用于后期验证。

@Controller
    @RequestMapping("/kaptcha")
    public class CaptchaController { 
            Producer captchaProducer = null;  
            @Autowired  
            public void setCaptchaProducer(Producer captchaProducer) {  
                this.captchaProducer = captchaProducer;  
            }  
            @RequestMapping("/doGet")  
            public ModelAndView doGet(HttpServletRequest request, HttpServletResponse response) throws Exception {  
                response.setDateHeader("Expires", 0);  
                // Set standard HTTP/1.1 no-cache headers. 
                response.setHeader("Cache-Control", "no-store, no-cache, must-revalidate");  
                // Set IE extended HTTP/1.1 no-cache headers (use addHeader). 
                response.addHeader("Cache-Control", "post-check=0, pre-check=0");  
                // Set standard HTTP/1.0 no-cache header. 
                response.setHeader("Pragma", "no-cache");  
                // return a jpeg 
                response.setContentType("image/jpeg");  
                // create the text for the image 
                String capText = captchaProducer.createText();  
                // store the text in the session 
                request.getSession().setAttribute(Constants.KAPTCHA_SESSION_KEY, capText);  
                // create the image with the text 
                BufferedImage bi = captchaProducer.createImage(capText);  
                ServletOutputStream out = response.getOutputStream();  
                // write the data out 
                ImageIO.write(bi, "jpg", out);  
                try {  
                    out.flush();  
                } finally {  
                    out.close();  
                }
                       System.out.println("Captchca:"+request.getSession().getAttribute(Constants.KAPTCHA_SESSION_KEY));
                return null;  
            }  
    
    }

## 前端 ##

主页这里为了不让验证码图片被缓存，需要在请求后边加入随机数。

function refreshCaptcha(){ 
        var ran = Math.floor(Math.random() * 100)
        $('#captcha1').attr('src','/webRoot/kaptcha/doGet?' + ran);
    }

# 验证码认证 #

将用户输入的字符串与Session中保存的验证码进行比较即可

@ResponseBody
        @RequestMapping(value="doLogin", method = RequestMethod.POST)
        public ResultInfo doLogin(HttpServletRequest request, HttpServletResponse response){
            ResultInfo result = new ResultInfo();
            String captcha = request.getParameter("captcha");
            if(!captcha.equals(request.getSession().getAttribute(Constants.KAPTCHA_SESSION_KEY))){
                result.setStateId(-1);
                result.setErrorMsg("验证码不正确");
                return result;
            }
            /*其它的登录代码*/
            return result;
        }