The technical principles of the AOP UTILITIES framework in the Java class library
The technical principles of the AOP UTILITIES framework in the Java class library
AOP (Aspect-Oriented Programming) is a programming paradigm that separates the functional module in the system as Cross-Cutting Concerns, thereby improving the modularization, maintenance and reuse of the code.The AOP Utilities framework is a Java class library that provides tools and functions to implement AOP programming.
The implementation principle of the AOP Utilities framework is based on proxy mode and dynamic proxy technology.In Java, there are two common proxy modes: static agents and dynamic agents.Static proxy requires developers to manually create proxy classes, and significantly call the method of being agent; dynamic proxy dynamically generates the agent class during runtime, and add additional logic to the agency class, such as executing before and after the method of the method.Some operations.
The AOP Utilities framework uses the dynamic proxy technology in Java to dynamically generate proxy classes at runtime to achieve AOP programming.It mainly involves the following core concepts and principles:
1. ASPECT: The cut surface is the key concept of AOP programming. It defines the code logic executed on the horizontal cutting point.The AOP Utilities framework provides a way that developers can define a cut -off class and write the logic that requires the execution before and after the method calls.
2. PointCut: What methods are defined by the cut point to be intercepted by the cut surface.The AOP Utilities framework provides a variety of ways to specify cut points, such as method names, annotations, parameter types, etc.
3. Notification (Advice): The notification defines specific logic executed on the cut point, common ones are BeFore Advices, after Advices, AFTER RETURNINGINGINGE, and AFTERThrowing advice) and so on.The AOP Utilities framework enables AOP by inserting notification logic before and after the method calls.
4. Proxy Factory: The proxy factory is a key component of dynamic proxy, which dynamically generates the proxy class during runtime.The proxy factory of the AOP Utilities framework will create a proxy class and insert the notification logic in the method of the proxy class according to the definition of the cut and cut points.
The use of a simple example to demonstrate the use of the AOP Utilities framework:
import com.aopframework.annotation.*;
@Aspect
public class LoggingAspect {
@Pointcut(value = "execution(* com.example.MyClass.doSomething(..))")
public void myMethod() {
}
@Before("myMethod()")
public void beforeMethod(JoinPoint joinPoint) {
System.out.println("Before method execution!");
}
@After("myMethod()")
public void afterMethod(JoinPoint joinPoint) {
System.out.println("After method execution!");
}
}
public class MyClass {
public void doSomething() {
System.out.println("Doing something...");
}
public static void main(String[] args) {
MyClass myObj = new MyClass();
myObj.doSomething();
}
}
In this example, we define a cut type called Loggingaspect and use the @Aspect annotation marking as the cut surface.In the cut -off class, we define a cut -point MyMethod (), which specifies the Dosomething () method to intercept the MyClass class.We then define the front notice and rear notification using @Beface and @AFTER annotations.
When running the main program, the Aop Utilities framework will generate the agent class of MyClass during runtime, and insert the logic of the front notice and rear notification in the agency class.In the output, we can see the "BeFore Method Execution!" And "After Method Execution!"
Through the AOP Utilities framework, we can separate cross -sectional attention points (such as logs, performance monitoring, etc.) from business logic, thereby improving the maintenance and reusability of the code.It uses the principle of dynamic proxy technology and cutting surface programming to make developers more conveniently implement AOP programming.
