Explore the technical principles of the Jakarta Interceptors framework in the Java library

Jakarta Interceptors Framework Technical Principles Inquiry Overview: Jakarta Interceptors is a Java -based framework that is used to realize the design ideas of AOP (facing surface programming) in the application.It provides a mechanism that can insert the logic of code logic at the key points of the application (such as method calling, abnormal processing, transaction management, etc.) to realize the functions of cross -section attention points, log records, performance monitoring and other functions.This article will explore the technical principles of Jakarta Interceptors and how to use it in the Java library. Jakarta interceptors working principle: The Jakarta Interceptors framework is implemented based on Java's reflection mechanism.It creates the interceptor chain and binds it to the target class or method to achieve AOP.When the target class or method is called, each interceptor in the interceptor chain will be called in a certain order to perform specific logic. In Jakarta Interceptors, the following are some core concepts and their working principles: 1. Interceptor: The interceptor is the part of the actual execution logic.They can insert code before, after, or around the target method.The interceptor may be any class that implements a class that implements javax.interceptor.inVocationContext interface. 2. Interceptor Chain: The interceptor chain is a collection of a series of interceptors, which are executed in order in the order of definition.It can be configured by defining annotations on a class or method. 3. Target class: The target class is a class that needs to be intercepted, which contains methods to be executed.The interceptor can be executed before, behind or around the target method. 4. Join Point: The intercept point refers to the specific time point of the method of the method execution, which can insert the code logic of the interceptor at this time point.For example, method calls, throw abnormalities, etc. Java code example of JAKARTA Interceptors: The following is a simple Java code example, demonstrating how to use the Jakarta Interceptors framework: // Import related classes import javax.annotation.PostConstruct; import javax.inject.Inject; import javax.interceptor.AroundInvoke; import javax.interceptor.InvocationContext; // Define a interceptor class public class LoggingInterceptor { // Add log logic before and after the method execution @AroundInvoke public Object logMethod(InvocationContext context) throws Exception { System.out.println ("Method call:" + context.gettarget (). GetClass (). Getsimplename () + " -> " + context.getMethod().getName()); // Perform the interception method Object result = context.proceed(); System.out.println ("Method call:" + context.gettarget (). GetClass (). Getsimplename () + " -> " + context.getMethod().getName()); return result; } // Add initialization logic after classification @PostConstruct public void init(InvocationContext context) { System.out.println ("after instantiation:" + context.gettarget (). Getclass (). Getsimplename ()); } } // Define a target class public class MyClass { // Apply a loggingInterCepptor interceptor for the target method @Interceptors(LoggingInterceptor.class) public void myMethod() { System.out.println ("Performing Target Method"); } } // main class public class Main { public static void main(String[] args) { MyClass myObj = new MyClass(); myObj.myMethod (); // Call the target method } } In the above example, LoggingInterceptor is a interceptor class.By using the @Interceptors (LoggingInterceptor.class) annotation on the target method, the loggingInterceptor interceptor is applied to the target method mymethod ().When mymethod () is called, LoggingInterceptor will insert the code logic of the logic of log logic before and after execution. in conclusion: The Jakarta Interceptors framework provides a simple way to implement AOP in Java applications.It can create the addition and expansion of cross -sectional attention by creating a interceptor chain and applying it to the target class or method.By flexibly using the interceptor, developers can realize logistics, performance monitoring, transaction management and other functions, and improve the maintenance and scalability of the application.