AOP Utilities framework technical principle in the Java class library
AOP in the Java class library (facing the cut -off program) Utilities framework technical principles
Overview:
AOP is a programming paradigm. Its main idea is to separate the horizontal section attention points (such as log records, transaction management, etc.) from business logic, and dynamically weave it into different parts of the application during the program operation.AOP Utilities is a framework provided in the Java library to achieve cut -oriented programming.This article will introduce the principle of AOP Utilities and give some examples of Java code.
AOP background:
In traditional object -oriented programming, we usually combine attention points and business logic together, causing the maintenance of code to reduce the maintenance and reduction of the code.The AOP has separated the horizontal section attention point from the business logic, which increases the degree of modularity of the code, making the modification and expansion of the attention points easier.
Principle of AOP Utilities:
The AOP Utilities framework is based on Java's reflection mechanism.It dynamically woven the logic of the cut surface into the method of the target object by using the proxy object during runtime to achieve the function of the cut surface.
1. Define the logic of cutting surface:
First of all, we need to define the logic of the cutting surface, that is, the logic of the implementation before or after the method of the target object is executed.These cutting logic can be logging, abnormal processing, performance calculation, etc.Generally, we encapsulate the cutting logic into a class that implements the cut interface.
Example code:
public interface LoggingAspect {
void logBefore(String methodName);
void logAfter(String methodName);
}
public class LoggingAspectImpl implements LoggingAspect {
@Override
public void logBefore(String methodName) {
System.out.println("Before " + methodName);
}
@Override
public void logAfter(String methodName) {
System.out.println("After " + methodName);
}
}
2. Create proxy objects:
Next, we need to create an agent object that can call the cutting logic before and after the method of the target object.AOP Utilities provides a ProxyFactory class that helps us create proxy objects dynamically.
Example code:
LoggingAspect loggingAspect = new LoggingAspectImpl();
MyTargetObject targetObject = new MyTargetObject();
ProxyFactory proxyFactory = new ProxyFactory();
proxyFactory.setTarget(targetObject);
proxyFactory.addAspect(loggingAspect);
MyTargetObject proxyObject = (MyTargetObject) proxyFactory.getProxy();
3. Execute the target method:
Now, we can use proxy objects to execute the target method.Before and after the target method is executed, AOP Utilities automatically calls the cutting logic.
Example code:
proxyObject.doSomething();
Summarize:
The AOP Utilities framework provides a way to facilitate cutting -oriented programming.Through dynamic proxy technology, it dynamically woven the logic of cutting surface into the method of target objects, so that we can separate attention points from business logic and increase the degree of modularization of code.Using AOP Utilities, we can implement logi records, transaction management and other functions, thereby improving the maintenance of code and reusedability.
The above is an introduction to the technical principles of the AOP Utilities framework in the Java library.It is hoped that the article can help readers understand the principle of AOP and use the AOP Utilities framework to achieve cutting programming.
