Spring cache @Cacheable and @CachePut. If exception is thrown inside method of @cachePut, get data from Cache

Question

I have a spring cache requirement:

I need to request to a server to get some data and store the results in spring cache. The same request can give me different results every time so I decided to use @cachePut so that every time I can go inside my function and cache gets updated.

@CachePut(value="mycache", key="#url")
public String getData(String url){
    try{
        // get the data from server
        // update the cache
        // return data
    } catch(){
        // return data from cache
    }   
}

Now there is a twist. If the server is down and I am not able to get the response; I want my data from the cache (stored in previous requests).

If i use @Cacheable, I can't get the updated data. What is the clean way to do this? Something like catching an exception and return the data from cache.

Answer 1

you can get the cache implementation like this and handle the cache.

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.Cache;
import org.springframework.cache.CacheManager;
import org.springframework.cache.annotation.CacheConfig;
import org.springframework.cache.annotation.CachePut;
import org.springframework.stereotype.Service;

@Service
@CacheConfig(cacheNames="mycache") // refer to cache/ehcache-xxxx.xml 
public class CacheService {
    @Autowired private CacheManager manager;
    @CachePut(key="#url")
    public String getData(String url) {
        try {
            //do something.
            return null;
        }catch(Exception e) {
            Cache cache = manager.getCache("mycache");
            return (String) cache.get(url).get();
        }
    }
}