本文主要介绍拦截器(Interceptor)
spring boot 版本 : 2.4.5
实现方式有 :
AsyncHandlerInterceptor或HandlerInterceptor
spring 5.3 HandlerInterceptorAdapter 已弃用

一:定义拦截器

@Component
@Slf4j
//统计方法执行时间
public class TimeInterceptor implements HandlerInterceptor {
 
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        log.info("在请求处理之前进行调用（Controller方法调用之前）");
        request.setAttribute("startTime", System.currentTimeMillis());
        HandlerMethod handlerMethod = (HandlerMethod) handler;
        log.info("controller object is {}", handlerMethod.getBean().getClass().getName());
        log.info("controller method is {}", handlerMethod.getMethod());

        // 需要返回true，否则请求不会被控制器处理
        return true;
    }

    /*@Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        log.info("请求处理之后进行调用，但是在视图被渲染之前（Controller方法调用之后），如果异常发生，则该方法不会被调用");
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        log.info("在整个请求结束之后被调用，也就是在DispatcherServlet 渲染了对应的视图之后执行（主要是用于进行资源清理工作）");
        long startTime = (long) request.getAttribute("startTime");
        log.info("time consume is {}", System.currentTimeMillis() - startTime);
    }*/
}