Is the transient modifier my friend ? Are @Transient annotation and the transient modifier related or not a all ?

他们并没有真正相关,但我担心他们不会成为你的朋友,Hibernate / JPA不会保留瞬态属性. JPA规范如下：

2.1.1 Persistent Fields and Properties

The persistent state of an entity is
accessed by the persistence provider
runtime either via JavaBeans style
property accessors or via instance
variables. A single access type (field
or property access) applies to an
entity hierarchy. When annotations are
used,the placement of the mapping
annotations on either the persistent
fields or persistent properties of the
entity class specifies the access type
as being either field – or property –
based access respectively.

• If the entity has field-based access,the persistence provider
  runtime accesses instance variables
  directly. All non-transient
  instance variables that are not
  annotated with the Transient
  annotation are persistent. When
  field-based access is used,the
  object/relational mapping annotations
  for the entity class annotate the
  instance variables.
• If the entity has property-based access,the persistence provider
  runtime accesses persistent state via
  the property accessor methods. All
  properties not annotated with the
  Transient annotation are persistent.
  The property accessor methods must be
  public or protected. When
  property-based access is used,the
  object/relational mapping annotations
  for the entity class annotate the
  getter property accessors.
• Mapping annotations cannot be applied to fields or properties that
  are transient or Transient.
• The behavior is unspecified if mapping annotations are applied to
  both persistent fields and properties
  or if the XML descriptor specifies use
  of different access types within a
  class hierarchy.

…

参考

> JPA 1.0规范

>第2.1.1节持久字段

> Hibernate核心参考指南

> 2.2.2. Mapping simple properties

相关问题

> Why does JPA have a @Transient annotation?