springboot拦截器+自定义注解拦截未登陆用户

1. 继承HandlerInterceptorAdapter类并实现preHandler()方法,被拦截的请求在调用controller层之前将先调用preHandler()方法第一步处理请求。

public class LoginInterceptor extends HandlerInterceptorAdapter {

    private static final Logger logger = LoggerFactory.getLogger(LoggerFactory.class);

    @Autowired
    private CookieUtil cookieUtil;

    /**
     * 访问controller前调用
     * @param request
     * @param response
     * @param handler
     * @return
     * @throws Exception
     */
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        logger.info("preHandler");
        // 被@RequestMapping注解修饰的controller方法就是HanglerMethod
        // A.isAssignableFrom(B),判断A与B是否是同一个class，A是否是B的超类或者超接口，是返回true，否返回false
        if (!handler.getClass().isAssignableFrom(HandlerMethod.class)) {
            System.out.println("cat cast handler to HandlerMethod.class");
            return true;
        }
        HandlerMethod method = (HandlerMethod)handler;
        // 获取controller方法上的注解
        NeedLogin needLogin = method.getMethodAnnotation(NeedLogin.class);
        if (needLogin == null){
            return true;
        }

        String paramToken = request.getParameter(CookieUtil.COOKIE_NAME);
        String cookieToken = cookieUtil.getLoginToken(request);
        if (StringUtils.isEmpty(paramToken) && StringUtils.isEmpty(cookieToken)){
            return false;
        }
        String token = paramToken == null ? cookieToken:paramToken;
        SecondKillUser user = cookieUtil.getUserByToken(token,response);
        return  user == null ? false : true;
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        super.postHandle(request, response, handler, modelAndView);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        super.afterCompletion(request, response, handler, ex);
    }

    @Override
    public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        super.afterConcurrentHandlingStarted(request, response, handler);
    }

2. 注册拦截器，将拦截器类放入spring容器当中，否则无法注入其它bean

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {

   /**
   *注册拦截器
   /
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(loginInterceptor()).addPathPatterns("/**");
    }

    @Bean
    public LoginInterceptor loginInterceptor(){
        return new LoginInterceptor();
    }
}