实体是否应该有行为?

say they're practicing SOA

Object-Oriented Anti-Pattern - Data Objects with Behavior

book.Write();  
book.Print();   
book.Publish();  
book.Buy();  
book.Open();   
book.Read();  
book.Highlight();  
book.Bookmark();  
book.GetRelatedBooks();   

Book book = author.WriteBook();  
printer.Print(book);  
publisher.Publish(book);  
customer.Buy(book);  

reader = new BookReader();   

reader.Open(Book);   

reader.Read();  
reader.Highlight();  
reader.Bookmark();  

librarian.GetRelatedBooks(book);