Learn about the technical principles of the JAKARTA Interceptors framework in the Java library and its application scenario Plication SCENARIOS)

Article Title: Learn about the technical principles and application scenarios of the Jakarta Interceptors framework in the Java class library Abstract: This article will introduce the technical principles of the Jakarta Interceptors framework in the Java class library and its scenes in practical applications.Jakarta Interceptors is a powerful interceptor framework that dynamically injects the interceptor by dynamically injected the interceptor during the method call process.This article will explore the core principles, basic usage and several common application scenarios of the framework, and provide corresponding Java code examples. 1. Framework Overview Jakarta Interceptors is a core component in the Java class library, which aims to solve the processing problem of horizontal cutting attention.The horizontal cutting focus refers to the functional requirements that have nothing to do with core business logic but have common functional needs in the entire application, such as log records, transaction management, performance monitoring, etc.By using the Jakarta Interceptors framework, these common functions can be decoupled from the core code, making the core code more concise and maintainable. 2. Technical principles The core technical principles of the Jakarta Interceptors framework are based on proxy mode and decorative mode.When a class is marked as an interception, a proxy object will be dynamically generated in the method call chain. The proxy object plays an intermediate role between the interceptor and the target object.During the method call process, the proxy object will trigger the logic of the interceptor in accordance with certain rules, so as to achieve a unified processing of cross -section attention points. 3. Basic usage The basic steps of using the Jakarta Interceptors framework are as follows: (1) Define a interceptable target class, and use the @Interceptors annotation to mark the class. (2) Define a interceptor class and achieve corresponding interception logic. (3) Use the @Interceptor annotation mark in the interceptor class, and use the @AroundinVoke annotation to achieve the interception logic. (4) Use the @InterCepTors annotation in the target class and specify the interceptor class. (5) Compile and run the program to observe the execution effect of the interceptor. The following is a simple example code: @Interceptors(LoggingInterceptor.class) public class MyService { public void doSomething() { System.out.println("Doing something..."); } } @Interceptor public class LoggingInterceptor { @AroundInvoke public Object logMethodInvocation(InvocationContext context) throws Exception { System.out.println("Before method: " + context.getMethod().getName()); Object result = context.proceed(); System.out.println("After method: " + context.getMethod().getName()); return result; } } public class Main { public static void main(String[] args) { MyService service = new MyService(); service.doSomething(); } } In the above examples, the MyService class is marked as interception and specifies the loggingInterceptor as an interceptor.In LogmenthodinVocation methods in LoggingInterceptor, we can define the logic of executing before and after the target method call.Finally, by creating the MyService object and calling the Dosomething method, the execution effect of the interceptor can be observed. 4. Application scenario Jakarta Interceptors has a wide range of application scenarios in the Java application, such as: -Rog record: You can call the logging function by recording the information in the interceptor. -Affective management: You can control the beginning and submission of transactions in the interceptor to achieve transaction management functions. -Puctic monitoring: You can record performance indicators such as the method of execution time in the interceptor, and perform performance monitoring and statistics. Summarize: This article introduces the technical principles and application scenarios of the Jakarta Interceptors framework in the Java class library.By understanding the core principles of the framework, we can better use the interceptor to decouple the cross -section attention point and achieve unified treatment of common functions.I hope that this article can understand you to understand the Jakarta Interceptors framework and be able to apply it in actual development. Reference materials: -JAKARTA interceptors official document: https://jakarta.ee/specifications/interceptors/