Apache Servicemix :: Bundles :: Spring Aop Implementation Principles Analysis of Principles
Apache Servicemix :: Bundles :: Spring Aop Implementation Principles Analysis of Principles
Apache ServiceMix is an open source corporate service bus (ESB), which provides a flexible integration solution for constructing and managing distributed applications.This article will introduce an important component bundled by Apache Servicemix -Spring AOP (facing cut -faced programming) and analyzes its implementation principles.
Facing surface programming (AOP) is a programming paradigm that is used to separate the function of the application through cross -sectional followers.In AOP, the function of the application is divided into core business logic and horizontal focusing point.The core business logic contains the main functions of the program, and the cross -section attention point is the function of sharing with multiple modules or objects, such as log records, transaction management or security.By being separated from the core business logic from the core business logic, the maintenance of the program can be improved.
Spring AOP is an important feature of the Spring framework. It provides a ability to apply cross -cutting points to the Java object.The Spring AOP is based on a dynamic proxy mechanism. It generates proxy objects and applies proxy objects to target objects by runtime, thereby achieving the function of cross -cutting attention points.Spring AOP supports two types of agents: JDK -based interface agents and CGLIB -based proxy.
The JDK -based interface agent is achieved through the Java.lang.reflet.proxy class provided by the Java standard library.The proxy object can implement the same logic before and after the method calls the same interface as the target object, to achieve cross -sectional attention points.However, JDK -based interface agents can only achieve the target object of the interface.
The CGLIB -based agent is achieved by the Enhancer class provided by the CGLIB library.The proxy object inherits the class of the target object and perform additional logic before and after the method calls to achieve cross -sectional attention points.Compared with JDK -based interface agents, CGLIB -based agents can proxy the target object that does not achieve the interface.
In Apache ServiceMix, the implementation of Spring AOP is bundled into an independent module and can be used as an insertable component.By introducing the Spring AOP module in Servicesmix, developers can easily apply the programming function to the corporate service bus.
Here are a simple example of using Spring AOP:
First, define a interface HelloWorld:
public interface HelloWorld {
void sayHello(String name);
}
Then, implement the target object of the HelloWorld interface:
public class HelloWorldImpl implements HelloWorld {
public void sayHello(String name) {
System.out.println("Hello, " + name + "!");
}
}
Next, define a cut -type loggingaspect, which is used to execute additional log logic logic before and after the method of the target object:
public class LoggingAspect {
public void beforeAdvice(JoinPoint joinPoint) {
System.out.println("Before calling method: " + joinPoint.getSignature().getName());
}
public void afterAdvice(JoinPoint joinPoint) {
System.out.println("After calling method: " + joinPoint.getSignature().getName());
}
}
Finally, declare the cutting surface and target object in the Spring configuration file, and apply the cut surface to the target object:
<bean id="helloWorld" class="com.example.HelloWorldImpl" />
<bean id="loggingAspect" class="com.example.LoggingAspect" />
<aop:config>
<aop:aspect ref="loggingAspect">
<aop:before method="beforeAdvice" pointcut="execution(* com.example.HelloWorld.*(..))" />
<aop:after method="afterAdvice" pointcut="execution(* com.example.HelloWorld.*(..))" />
</aop:aspect>
</aop:config>
In the above example, the BeforeAdvice method of the LoggingAspect class is executed before the HelloWorldIMPL method is called, and the Afterradvice method is executed after the method calls.By defining the cutting point of the cut surface and the application of the cut surface, the function of cross -cutting attention can be achieved.
In summary, the Spring AOP module bundled by Apache Servicemix implements the function of cutting -oriented programming through a dynamic agency mechanism.By using Spring AOP, developers can separate cross -cutting attention points from the core business logic and apply it as an insertable component to the enterprise service bus.The above examples demonstrate how to configure and use Spring AOP in Spring.
I hope the analysis provided in this article will help you better understand the principles of Spring AOP bundled by Apache Servicemix.
