Spring的AsyncHandlerInterceptor

AsyncHandlerInterceptor提供了一个afterConcurrentHandlingStarted()方法, 这个方法会在Controller方法异步执行时开始执行, 而Interceptor的postHandle方法则是需要等到Controller的异步执行完才能执行

例如

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
        System.out.println(11111);
    }

    @Override
    public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println(22222);
    }

@ResponseBody
    @RequestMapping(value = "/topQuery")
    public DeferredResult<Object> topQuery(@RequestParam String token,
            @RequestParam(required = false, defaultValue = "") String tn,
            @RequestParam(required = false, defaultValue = "baiduhui") String zt) {
        topQueryCounter.increment();
        DeferredResult<Object> dr = new DeferredResult<Object>();
        Map<String, Object> extra = Maps.newHashMap();
        extra.put(TN_KEY, TN_KEY + "=" + tn);
        extra.put(ZT_KEY, ZT_KEY + "=" + zt);
        topQueryService.fetchData(dr, "limit=" + topQueryLimit, 1, new AtomicInteger(0),
                new ArrayList<BaiduTopQuery>(), extra);
        return dr;
    }

afterConcurrentHandlingStarted()方法会在return dr后执行, 而postHandle()方法则需要dr.setResult()以后才会执行