Java Dynamic proxy (automatic proxy), AOP

AOP
: Cross-section programming.
, Connection point
{Pre-notification, surround notification, and post-Notification} in this example, the surround notification is used.
(Specify the method that requires proxy ).

Spring 1.2 is used.

Take person as an example:

 

Iperson interface (which can be understood as a business interface ):

 

Public
Interface

Iperson {

Public void sleep ();
Public void walk ();

}

 

Iperson implementation class (which can be understood as a business implementation class ):

 

Public

Class

PersonimpImplements

Iperson {

Public

Void sleep (){
System. Out
. Println ("sleep..."); // specific business operation, such as inserting data into a database

}

Public

Void walk (){
System. Out
. Println ("walk..."); // specific business operation, such as inserting data into a database

}

}

Define the connection point (
Pre-notification | surround notification
|
Post-Notification} surround notification is used here
If you use a pre-notification, or a post-notification, it is easier ):

 

Public

Class

AroundnoteImplements

Methodinterceptor {

Public

Object invoke (methodinvocation arg0)Throws

Throwable {

System. Out
. Println ("befor"); // For example, the Service Code, such as opening a transaction

Object o = arg0.proceed ();
System. Out
. Println ("after"); // For example, service code, such as transaction commit and rollback

Return

O;
}
}

 

Test class:

 

Public

Class

Proxytest {

Public

Static

Void main (string [] ARGs ){

Applicationcontext AC =New

Classpathxmlapplicationcontext ("applicationcontext. xml"); // enable the spring container and load the configuration

Iperson person = (iperson) AC. getbean ("personimp"); // obtain the target object (business class)


Person. Sleep ();
Person. Walk ();

}
}

/* Above analysis: When sleep is executed, run system. Out in the connection point first.
. Println ("befor ");
Run this code, then run sleep and finally execute system. Out.
. Println ("after ");
If hibernate operates the database in sleep, then system. Out
. Println ("befor ");
This code is changed to enable the transaction, system. Out
. Println ("after ");
This code is changed to the commit of the transaction, so all the transactions can be completed in this way, and the transactions and services are separated. */

 

Output result:

 

Befor // if the transaction is enabled

Sleep... // operation on the database

After // if the transaction is committed or rolled back

Befor
Walk...
After

Spring Configuration:

 

<? XML
Version
= "1.0"
"Encoding
= "UTF-8
"?>

<Beans

Xmlns
= "Http://www.springframework.org/schema/beans
"
Xmlns
: Xsi
= "Http://www.w3.org/2001/XMLSchema-instance
"
Xsi: schemalocation
= "Http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
">

<! -- Target object (business class) -->


<Bean
ID
= "Personimp
"Class
= "Org. LC. autoproxy. personimp
"> </Bean>


<! -- Surround notification AOP {jointpoint (connection point)} -->

<Bean
ID
= "Aroundnote
"Class
= "Org. LC. autoproxy. aroundnote
"> </Bean>


<Bean
Class
= "Org. springframework. AOP. Framework. autoproxy. beannameautoproxycreato

R
">

<! -- If the name is the setbeannames method in beannameautoproxycreator, the following is the same -->

<Property
Name
= "Beannames
">

<Value>
Personimp </value>

</Property>


<! -- Specify the connection point -->

<Property
Name
= "Interceptornames
">

<List>
<Value>
Aroundnote </value>
</List>

</Property>
</Bean>

</Beans>