In other words , each method invocation on the same persistence-context proxy injected through @ PersistenceContext will return a different entity-manager instance , which opens and closes immediately .
换句话说，对通过@PersistenceContext注入的同一持久化上下文代理的每个方法调用都将返回一个不同的实体管理器实例，且这些实例会立即打开而后关闭。
persistencecontext