Detach an entity from jpa/ejb3 persistence context

problem ：

What would be the easiest way to detach a specific JPA Entity Bean that was acquired through an EntityManager. Separation pass EntityManager Get specific JPA Entity Bean What's the easiest way to do it .Alternatively, could I have a query return detached objects in the first place so they would essentially act as 'read only'? perhaps , Can I first have the query return a separate object , So that they basically act as “ read-only ”？

The reason why I want to do this is becuase I want to modify the data within the bean - with in my application only, but not ever have it persisted to the database. The reason I want to do this is because I want to modify bean Data in - Use only in my application , But it is never persisted to the database .In my program, I eventually have to call flush() on the EntityManager, which would persist all changes from attached entities to the underyling database, but I want to exclude specific objects. In my program , I finally have to EntityManager On the call flush(), This saves all changes from the attached entity to the underlying database , But I want to exclude certain objects .

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Solution ：

Reference resources ： https://stackoom.com/en/question/8BC