How can I make a generic Spring Service to find entities and return only some fields-CodePudding

I have made a service that uses the entity manager to retrieve an entity given its name:

    public Object getEntity(long resourceId, String resource) throws EntityNotFoundException {
        try{
            Class<?> cls = Class.forName("com.example.package.models."   resource);
            Object resourceOpt = findById(cls, resourceId);


            if(resourceOpt == null){
                throw new EntityNotFoundException("Resource "   resource   " could not be found with id: "   resourceId);
            }

            return resourceOpt;
        }catch (ClassNotFoundException ex){
            throw new EntityNotFoundException("Resource "   resource   " could not be found with id: "   resourceId);
        }

    }

Where the "findById" does this:

public <T, ID> T findById(Class<T> type, ID id) {
        return entityManager.find(type, id);
    }

This works perfectly fine but I have a problem.

If I try to get the "User", the entity manager will return all the fields, including the password:

{
    "id": 1,
    "firstname": "name",
    "lastname": "surname",
    "email": "[email protected]",
    "password": "password",
    "role": "USER",
    "enabled": true,
    "username": "[email protected]",
    "authorities": [
        {
            "authority": "USER"
        }
    ],
    "accountNonLocked": true,
    "credentialsNonExpired": true,
    "accountNonExpired": true
}

How can I make it to retrieve only some fields? Should I use DTOs or JsonField annotations?

CodePudding user response：

If you application does not need to write users and never wants to expose the password then you can remove password from com.example.package.models.User.

Otherwise you need to use a DTO.