前后端分离时，获取不到session

@ApiOperation(value = "获取图片验证码", notes = "获取图片验证码")
    @RequestMapping(value = "/getCode",method = RequestMethod.GET)
    public void verfification(HttpServletRequest request, HttpServletResponse response, HttpSession session)throws IOException{
        // 设置响应的类型为图片格式
        response.setContentType("image/jpeg");
        // 禁止图片缓存
        response.setHeader("Pragma","no-cache");
        response.setHeader("Cache-Control","no-cache");
        response.setDateHeader("Expires",0);
        VerificationCode verificationCode = new VerificationCode();
        // 将验证码存入session
        session.setAttribute("verification", MD5.eccrypt(verificationCode.getCode().toLowerCase()));
        System.out.println(session.getId());
        verificationCode.write(response.getOutputStream());
    }

    @ApiOperation(value = "验证验证码是否正确", notes = "验证验证码是否正确")
    @ApiImplicitParam(name = "code",value = "图片验证码",required = true,dataType = "String")
    @RequestMapping(value = "/verification/{code}",method = RequestMethod.POST)
    public Response verfification(@PathVariable("code") String code,HttpSession session){
        System.out.println(session.getId());
        // 图片验证码
        if(!VerificationCode.isright(code.toLowerCase(),session)){
            return new Response("图片验证码错误！","图片验证码错误，请重新输入!");
        }
        return new Response(true,"图片验证码正确！","图片验证码成功!");
    }

@Configuration
public class CorsFilterConfiguration {

    @Bean
    public FilterRegistrationBean corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        CorsConfiguration config = new CorsConfiguration();
        // 允许跨域
        config.setAllowCredentials(true);
        // 设置允许跨域的域名，如：http://localhost:9004 如果为*号，则表示允许所有的
        config.addAllowedOrigin("*");
        config.addAllowedHeader("*");
        config.addAllowedMethod("*");
        source.registerCorsConfiguration("/**", config);
        FilterRegistrationBean bean = new FilterRegistrationBean(new CorsFilter(source));
        bean.setOrder(0);
        return bean;
    }
}