过滤器 Filter

重写 doFilter，init方法

让这个过滤器生效的方法：@Component

异步请求

callable

    @RequestMapping("/order")
    public Callable<String> order() throws Exception {
        logger.info("主线程开始");
        Callable<String> result = new Callable<String>() {
              @Override
              public String call() throws Exception {
                  logger.info("副线程开始");
                  Thread.sleep(1000);
                  logger.info("副线程返回");
                  return "success";
            }
        };
        logger.info("主线程返回");
    }