using ehcache in a dropwizard project

Question

I am using dropwizard to create a RESTful service. To avoid hammering the database, I am looking for a good caching solution in java. Searching the web lead me to ehcache. I have read the documentation a bit, but currently it is not clear to me how to use ehcache in a dropwizard project.

For instance, where does the configuration file go? I just need something to help me start using the cache.

If this is difficult to integrate, what would be the most suited caching solution for dropwizard project?

Thanks!

Answer 1

If you ultimately want a simpler (than ehcache) cache framework/API, consider using CacheBuidler from guava:

https://code.google.com/p/guava-libraries/wiki/CachesExplained

A typical cache implementation and use requires just a few lines of code and no configuration files.

Answer 2

I know this is an old question, but I have been able to set it up. Here's how.

1. Get the hibernate version. You can get this from the dependencies of dropwizard-hibernate package. eg. dropwizard-hibernate:1.3.12 depends on hibernate-core:5.2.18.Final .
2. Add ehcache matching the exact version of hibernate, so in this case compile group: 'org.hibernate', name: 'hibernate-ehcache', version: '5.2.18.Final'
3. Enable 2nd level caching on hibernate. Dropwizard manages configuration in config.yml. So this would be something like:

# For documentation on available options please refer io.dropwizard.db.DataSourceFactory
database:
  # any properties specific to your JDBC driver:
  properties:
    # Enable second level cache with EhCache
    hibernate.cache.use_second_level_cache: true
    hibernate.cache.region.factory_class: org.hibernate.cache.ehcache.EhCacheRegionFactory

4. Now, your cache should be enabled. You can now use annotations on entities to make them cacheable. see doc on @org.hibernate.annotations.Cache

I found this article to be a good start. https://www.baeldung.com/hibernate-second-level-cache . There are also other types of caches like query cache etc which may help depending on your use case.

Let me know if this helped.