通过Javascript获取链接的价值(Getting the value of a link by Javascript)

 即使Hibernate是最常用的JPA实现，我也会坚持使用规范API（JPA）。 
 所以EntityManager而不是Session 。 
 
 通常，您想编写自己的查询，因为查询具有最低程度的复杂性。 
 但特定的JPA / Hibernate方法不允许执行这种查询。 
 这些方法只处理简单的情况。 
 
 因此，作为一般规则，您应该在每次可能时都支持特定的JPA / Hibernate方法而不是自定义查询创建。 
 通常是避免使用JPQL编写boiler plate代码的捷径。 
 例如，如果你想从它的ID中检索一个实体，那么你没有任何价值来写一个如此简单的查询。 
 你将不得不编写锅炉板代码（创建查询，设置参数查询，执行查询）。 
 使用EntityManager.find(Class<T>, Object)是一种更简单也更清晰的方法，因为您不需要进一步了解行为。 
 
 请注意，Spring Data JPA进一步提供了更多方法来处理其他经典查询。 
 SimpleJpaRepository类就是一个很好的例子。 
 
 最后，请注意，在某些情况下，特定的JPA / Hibernate方法来操纵实体并不是一种选择。 
 与实体或EntityManager状态相关的操作只能用这些方法（ persist() ， flush()或refresh() ， clear() ...）执行。 

Even if Hibernate is the most commonly JPA implementation used, I would stick rather on the specification API (JPA). 
 So EntityManager rather than Session.
 
Generally you want to write your own queries as queries have a minimal level of complexity.
 But specific JPA/Hibernate methods don't allow to perform this kind of queries.
 These methods handle only simple cases.
 
So as a general rule, you should favor specific JPA/Hibernate methods over custom query creating at each time you may.
 It is often a shortcut to avoid writing boiler plate code with JPQL.
 For example if you want to retrieve a entity from its ID, you don't have any value to write at hand a so simple query.
 You will have to write boiler plate code (creating query, setting parameter query, executing query).
 Using EntityManager.find(Class<T>, Object) is a much simpler and also clearer approach as you don't need to go further to understand the behavior.
 
Note that Spring Data JPA goes still further by providing more methods to handle other classic queries.
 The SimpleJpaRepository class is a good example.
 
At last, note that in some cases, specific JPA/Hibernate methods to manipulate entities are not a choice.
 The operations related to the entities or the EntityManager state can be performed only with these methods (persist(), flush() or refresh(), clear(), ...).