Analysis of the technical principles of the JAKARTA Interceptors framework in the Java class library

The Jakarta Interceptors framework is part of the standard specification of the Javaee (Java platform enterprise), which is designed to implement the interceptor mode in the application.The interceptor mode is a design pattern that is used to insert additional processing logic before and after the method calls, which can be used to achieve logging, performance monitoring, transaction management and other functions. The technical principles of the Jakarta Interceptors framework are based on annotations and reflection mechanisms provided in the Javaee specification.Developers can realize their interception class to achieve interceptor interfaces, and use relevant note solutions to associate with target methods or classes. First of all, we need to define an interceptor class to achieve the `javax.interceptor.invocontext` interface, which provides the context information required for the interceptor method.The interceptor class should be added with `@interceptor` to indicate that it is a interceptor. Here are the interceptor class of an example: import javax.interceptor.AroundInvoke; import javax.interceptor.Interceptor; import javax.interceptor.InvocationContext; @Interceptor public class LoggingInterceptor { @AroundInvoke public Object intercept(InvocationContext context) throws Exception { // The logic executed before the method call System.out.println("Before method call: " + context.getMethod().getName()); // Call the target method Object result = context.proceed(); // The logic executed after the method call System.out.println("After method call: " + context.getMethod().getName()); return result; } } In the above examples, we define an interceptor class called `LoggingInterceptor` and implemented the` Intercept` method.This method uses the `@aroundinvoke` annotation mark, indicating that it will be called before and after the call method calls.In this method, we can write any interception logic. Next, we need to apply the interceptor class to the target method or class.You can use the `@Internetors` annotation to apply the interceptor class to the target method, or use the` Beans.xml` file to declare the full -limited name of the interceptor class in the deployment description. The following is the target class of an example. Apply the `loggingInterceptor` to one of the methods: import javax.interceptor.Interceptors; public class MyService { @Interceptors(LoggingInterceptor.class) public void performAction() { // Execute certain operations System.out.println("Performing action..."); } } In the above examples, we use the@interceptors` annotation on the `Performaction` method to apply the` loggingInterceptor` to this method. When the application is running, each time the target method that is intercepted by the `loggingInterceptor` is intercepted, the interceptor's` intercept` method will be executed.In this method, we can access the parameters, return values and other context information of the target method to perform the required processing logic. In summary, the Jakarta Interceptors framework is implemented based on the annotations and reflex mechanisms in the Javaee specification, allowing developers to design and apply intercepters to achieve additional processing logic.By defining the interceptor class and applying it to the target method or class, you can flexibly insert the block logic in the application.