Async和EhCache不适用于第二个用户登录

Question

I am trying to implement @async with @cacheable as below ..

@RequestMapping(value="ehcacheExample")
public ModelAndView loadehcacheExamplePage(HttpServletRequest request, HttpSession session, ModelAndView modelAndView) {

    cacheHelper.getDataUsingAsyncAndStoreInEhcache(userInfo, session);

    //diffetent execution
    ...

    return modelAndView;
}

And

@Cacheable(value="cacheKey")
public Future<String> getDataUsingAsyncAndStoreInEhcache(UserLoginSessionInfo userInfo,
        HttpSession session) {
    return ehcacheExampleDelegate.getDataUsingAsyncAndStoreInEhcache(userInfo,session);
}

@Async
public Future<String> getDataUsingAsyncAndStoreInEhcache(UserLoginSessionInfo userInfo, 
    HttpSession session) {

    //Async execution
    return new AsyncResult<String>(jsonInString);
}

Now as per my understanding this 'getDataUsingAsyncAndStoreInEhcache' method produces the result independent of the caller method,saves it in ehcache implementation. So, the next time I call an ajax method for getting the data from future, I am doing below implementation -

@RequestMapping(value="getCachedData")
    public @ResponseBody String getCachedData(HttpSession session) {
        UserLoginSessionInfo userInfo = HttpRequestSessionUtils.getLoggedinUserSessionInfo(session);

        Future<String> cachedData = cacheHelper.getDataUsingAsyncAndStoreInEhcache(userInfo, session);
        …
        return dataFromFuture; 

    }

Now my expectation is, if any other user logs in after the first user, for him cacheHelper.getDataUsingAsyncAndStoreInEhcache(userInfo, session) should not execute the whole method. Rather it should retrieve the data from Ehcache memory.

But it is not happening. I can assure that caching is working because in the same session if the user calls the getCachedData ajax call multiple times, it is returning the data from cache only. But the issue is happening with the cacheHelper.getDataUsingAsyncAndStoreInEhcache(userInfo, session) implementation (mentioned in the @RequestMapping(value="ehcacheExample") method).

Can you please help me understand why this method is executing in whole, everytime the user calls loadehcacheExamplePage method rather than retrieving it from cache when a second user logging in?

Answer 1

I see different possible issues here. First, there is a bug between caching and async in Spring. However, I don't think it is relevant to you since your CacheHelper and CacheHelperDelegate are not the same object.

Now, it's the Future that will get cached. Not the value returned by it. It's weird. But it should still work.

Finally, Spring uses by default the parameters as the cache key. In your case UserLoginSessionInfo userInfo, HttpSession session . These are highly user specific. So it's normal that for two different users, the method will be called. If that's not what you want, you probably do not need to pass these parameters. You can also tell Spring what to use as a key with @Cacheable(key=...) .