作者easy1 (e :) y)
看板java
标题Re: [问题] EJB Object / Interface ?
时间Tue Nov 14 07:02:15 2006
在 EJB Spec 2.0 後
session bean 和 entity bean
可以有(概念上)
remote client view 和 local client view 两种view
"view" 可以当作是 "使用bean的方法/观点"
(稍微具体一点)就是可以拥有
local home interface 和 local component interface
remote home interface 和 remote component interface
...通常如果指"remote" "remote"这个字可以被省略不讲 .......
local / remote 的不同(非常简略的列出...)
local 和 remote 可以同时存在 只是会依据不同环境或设计 被使用
remote:
+ 使用在分散式环境 不同JVM之间
- 效能低
+ Call by value
local:
+ 使用在同一JVM上
+ 效能高
+ Call by Reference
+ container managed relationship/persistence
+ 一定要在同一个EAR里
(实作上)java API里..有这些Interface ...可以对应上面
EJBHome 和 EJBObject (分别 extends java.rmi.Remote)
EJBLocalHome 和 EJBLocalObject
看来 EJB*Home 是用来存取使用 EJB*Object
EJB*Object 是用来存取使用 真正EJB的"实体"(instance)
(我把javadoc列出来 希望有懂的人 能再讲清楚一点 或指正
我觉得这些文件用字很不明确 也许都定义在spec里吧...)
EJBHome
The EJBHome interface must be extended by all enterprise Beans'
remote home interfaces.
An enterprise Bean's remote home interface defines the methods that
allow a remote client to create, find, and remove EJB objects,
as well as home business methods that are not specific to a bean instance
EJBObject
The EJBObject interface is extended by all enterprise Beans'
remote interfaces.
An enterprise Bean's remote interface provides the remote client view
of an EJB object. An enterprise Bean's remote interface defines the
business methods callable by a remote client.
EJBLocalHome
The EJBLocalHome interface must be extended by all enterprise Beans'
local home interfaces.
An enterprise Bean's local home interface defines
the methods that allow local clients to create, find, and remove EJB objects,
as well as home business methods that are not specific to a bean instance.
EJBLocalObject
The EJBLocalObject interface must be extended by all enterprise Beans'
local interfaces.
An enterprise Bean's local interface provides the local client view of
an EJB object. An enterprise Bean's local interface defines the business
methods callable by local clients.
--
PLUR
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