Detailed explanation of Jakarta Interceptors framework technical principles in the Java class library

Jakarta Interceptors is a framework technology in the Java class library that is used to achieve cut-oriented programming (AOP) in the application.It provides a convenient way to add additional logic processing in the scenes such as the method call before and after, abnormal processing and transaction management.Interceptors can be used in any Java class, whether it is EJB components, Servlet, JAX-RS resources or CDI Bean. The principle of the Jakarta Interceptors is to be achieved by defining the interceptor class and using annotations.The interceptor class is an ordinary Java class, which contains logic that requires the execution before and after the implementation of the target method.These interceptors can be synchronized or asynchronous, and can be executed after the method calls, when it is abnormal, and after completion. To use the interceptor in the target method, we need to add related annotations to the target method.Jakarta Interceptors provides some annotations, including@Aroundinvoke,@Beforeinvoke,@AFTERINVOKE,@Aroundtimeout, etc., and is used to specify the specific stage of the interceptor to be called at the specific stage of the method execution.These annotations can be used at the method level or class level. Below is an example code using Jakarta Interceptors: import javax.interceptor.AroundInvoke; import javax.interceptor.Interceptor; import javax.interceptor.InvocationContext; @Interceptor public class LogInterceptor { @AroundInvoke public Object logMethod(InvocationContext context) throws Exception { System.out.println("Before calling method: " + context.getMethod().getName()); try { return context.proceed(); } finally { System.out.println("After calling method: " + context.getMethod().getName()); } } } In the above example, we define a interceptor class `LogInterceptor`, using the@InternetR` annotation to identify it as a interceptor class.We also define a `Logmethod` method and use it on it to annotate the method, indicating that the method will be executed before and after the target method calls. Next, we can use the annotation of `@logintercept` to specify the interceptor class: import javax.interceptor.Interceptors; @Interceptors(LogInterceptor.class) public class ExampleClass { public void exampleMethod() { System.out.println("Executing exampleMethod"); } } In the above example, we used the `@INTERCEPTORS (logInterceptor.class)` in the `ExampleClass` to specify the` LOGINTERCEPTOR "interceptor class applied to the` ExampleMeththod` method.In this way, when calling the `ExampleMethod` method, the logic in the interceptor will be executed before and after the method calls. In summary, the Jakarta Interceptors framework technology is defined by defining the interceptor class and using annotations, and additional logic processing is added before and after the method call.It introduces the idea of cutting -oriented programming into the Java application and provides a flexible and reusable way to handle universal cross -cutting attention points, such as logs, transaction management, and abnormal processing.