Cache invalidation in Ehcache

I am开发者_如何学Go using Ehcache in Hibernate.

How can I notify the cache that the database has changed? How can I invalidate the cached data? How can I programmatically achieve this?

What do exactly mean? There are 2 ways to make a change in the database: inside the app & outside the app

Inside the app you can trigger easily an invalidation. The second one is a harder to solve. Cache elements are stored with a key and based on that key you can delete it.

CacheManager manager = CacheManager.getInstance();
cache = manager.getCache(cacheName);
cache.remove(key);

or 

cache.removeAll();

Depending how you configured ehcache of course. But you need to know the name of the cache that holds the object.

This is how you can invalidate all EhCache items without bothering what the individual cache names are:

CacheManager manager = CacheManager.getInstance();

String[] names = manager.getCacheNames();

for (String name : names)
{
    Cache cache = manager.getCache(name);

    cache.removeAll();
}

Try:

CacheManager.create().clearAll()

It will clear all caches in CacheManager.

To clear only one particular cache, get it from cache manager and remove all elements:

CacheManager cacheManager = CacheManager.create();
Ehcache cache = cacheManager.getEhcache(cacheConfiguration.getName());
cache.removeAll();    

Set cache expiration so data is refreshed as or more often than the database changes .

Also you can update in cache only elements that change in the database .

In case if you want to remove a specific cache (eg:employeeCache)

@Autowired
CacheManager cacheManager;

place where you want to invalidate cache, use below code

    Cache cache = cacheManager.getCache("employeeCache");
    cache.removeAll();