Detailed explanation of how to use AspectJ to implement AOP in Spring

AspectJ describes tangent and enhancement through annotations.

1 Development environment requirements

Because you want to use annotations, make sure you are using Java 5.0 and above.

Introducing AspectJ related class library:

<dependency>
 <groupId></groupId>
 <artifactId>aspectjrt</artifactId>
 <version>${}</version>
</dependency>
<dependency>
 <groupId></groupId>
 <artifactId>aspectjweaver</artifactId>
 <version>${}</version>
</dependency>
<dependency>
 <groupId></groupId>
 <artifactId>aspectjtools</artifactId>
 <version>${}</version>
</dependency>
<dependency>
 <groupId>aopalliance</groupId>
 <artifactId>aopalliance</artifactId>
 <version>${}</version>
</dependency>

2 Programming methods

@Aspect//Identify facets

public class PreRentAspect {
 /**
   * Enhanced logic
   */
 @Before("execution(* rent(..))")//Define the tangent and enhancement types public void beforeRent() {
  ("Start the rental action");
 }
}

This section is just an ordinary POJO, but the @Aspect annotation is added.

@Before("execution(* rent(..))") In-house@Before It means that the enhancement type is a pre-enhanced enhancement, and its content is a @AspectJ point-cut expression. Here it means that the enhancement is weaved on the target class's rent() method. rent() can contain any incoming parameters and any return value.

bring@Aspect The class, through annotation and code, integrates the tangent point, enhancement type and enhanced cross-cutting logic together. Isn't it very convenient? O(∩_∩)O Haha~

Unit Tests:

AspectJProxyFactory factory = new AspectJProxyFactory();

//Set target class(new User());

//Add a facet class();

User proxy = ();
String userId = "001";
(userId);
(userId);

Output result:

--Start the rental action-
User: Rental [Power Bank]
User: Return [Power Bank]

3 Configuration method

<!-- Target class-->
<bean  class="."/>

<!-- Face-cut-->
<bean class="."/>

<!-- Automatically create a proxy-->
<bean
  class=""/>

Unit Tests:

ApplicationContext context = new ClassPathXmlApplicationContext(");
User user = (User) ("user");
String userId = "001";
(userId);
(userId);

The output is exactly the same as the program.

It can also be configured based on Schema's aop namespace:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="/schema/beans"
  xmlns:xsi="http:///2001/XMLSchema-instance"
  xmlns:aop="/schema/aop"
  xsi:schemaLocation="/schema/beans /schema/beans/spring-beans-4. /schema/aop /schema/aop/">

 <!--aspectj Drive -->
 <aop:aspectj-autoproxy/>

 <!-- Target class-->
 <bean  class="."/>


 <!-- Face-cut-->
 <bean class="."/>
</beans>

This configuration is simpler. Actually <aop:aspectj-atuoproxy/> The automatic proxy mode has been adopted inside. O(∩_∩)O Haha~

<aop:aspectj-atuoproxy/> ofproxy-target-class The property, defaults to false, means using JDK dynamic proxy technology to weave enhancement; if this value is true, means using CGLib dynamic proxy technology to weave enhancement. If the target class does not declare the interface, then even proxy-target-classSet to false, and the enhanced yo(∩_∩)O will be automatically weave the enhanced yo(∩_∩)O haha~

For projects based on Java5.0+, it is recommended to use AspectJ to configure point-cutting and enhancement, because this is simpler and more direct.

The above is all the content of this article. I hope it will be helpful to everyone's study and I hope everyone will support me more.