title: Setting createdBy and updatedBy in JPA entities automatically
body: <p>I'm working on a JPA (Hibernate implementation of), Spring and Stripes web app. I have a number of JPA entities that have the following fields in common for both audit and query purposes:</p>
  
  <p>createdBy - the user ID of the person who created the entity.
  createdOn - the date the entity was created
  updatedBy - the user ID of the person who last updated the entity
  updatedOn - the date the entity was last updated</p>
  
  <p>I've got my app working so that createdOn and updatedOn are set automatically when the entity is persisted but I'm not sure how I can get the createdBy and updatedBy fields populated without having to pass through the currently logged in user's ID all the way from the controller class to the DAOs. </p>
  
  <p>Does anyone have any suggestions on how I might do this without passing userIDs all over the place? Note that the current user ID is stored in the HttpSession object at the moment, so my backend needs to somehow access this data...</p>
  
  <p>Thanks!</p>