Comprehensive analysis of the technical principles of JAKARTA Interceptors in Java Library
Comprehensive analysis of the technical principles of JAKARTA Interceptors in Java Library
The Jakarta Interceptors framework in the Java class library is a powerful and flexible technology that makes it possible to inject and interact with the interceptor that can be injected and interactive during code execution.This article will comprehensively analyze the basic principles of the Jakarta Interceptors framework and provide Java code examples to help readers better understand.
1. What is an interceptor?
The interceptor is a component that can intercept and process specific methods to call or process a specific method call or event during the program execution.The interceptor can be used to achieve Cross-Cutting Concerss, such as log records, performance monitoring, security, etc.Under normal circumstances, the interceptor can achieve these functions by adding additional logic before and after the target method.
2. Overview of Jakarta Internet
The Jakarta Interceptors framework is part of the Java EE platform and is used to define and use the interceptor.It provides a set of standard APIs and annotations that allow developers to easily create and configure the interceptor and apply it to the target method or event.
3. Jakarta Internet
The principle of the Jakarta Interceptors framework is based on the dynamic agency mechanism of Java.When a target method or event is called, the framework uses a dynamic agent to create a proxy object, which will pack the target object and perform additional logic (that is, the logic of the interceptor).
3.1 Create a interceptor
First, we need to create a interceptor class.The interceptor class is an ordinary Java class that needs to implement the `javax.interCepptor.interceptor` interface provided by the Jakarta Interceptors framework.
import javax.interceptor.AroundInvoke;
import javax.interceptor.Interceptor;
import javax.interceptor.InvocationContext;
@Interceptor
public class LoggingInterceptor {
@AroundInvoke
public Object logMethod(InvocationContext context) throws Exception {
System.out.println("LoggingInterceptor: Before method execution");
Object result = context.proceed();
System.out.println("LoggingInterceptor: After method execution");
return result;
}
}
In the above examples, we created a interceptor class called `LoggingInterceptor` and implemented the` logmethod` method.In the `Logmethod` method, we can write the logic we want to execute before and after the implementation of the goal method.
3.2 Use the interceptor
Once we create the interceptor class, we can apply it to a specific target method or event.To this end, we need to use annotations provided by the Jakarta Interceptors framework.
import javax.interceptor.Interceptors;
public class ExampleClass {
@Interceptors(LoggingInterceptor.class)
public void doSomething() {
System.out.println("Doing something...");
}
}
In the above examples, we used the@interceptors` annotation on the `dosomething` method, and specify the class of the` loggingInterceptor` we created before.In this way, the logic in the interceptor will be executed when the `dosomething method is called.
4. Advantages and application scenarios of Jakarta Interceptors
-The height scalability: Jakarta Interceptors framework allows developers to define their interceptors and apply it to specific target methods or events.
-Couple attention point: By abstracting the cross-cutting concesss as a interceptor, we can decompose the core logic of the application with other focus points to improve the maintenance and reused of code.
-The horizontal cutting logic: The interceptor can be used to achieve horizontal cutting logic, such as log records, performance monitoring, security, etc.
Summarize:
Through the Jakarta Interceptors framework, developers can easily use and create interceptors to apply it to specific methods or events to achieve the function of Cross-Cutting Concers.This article comprehensively analyzes the principle of the Jakarta Interceptors framework, and provides Java code examples to help readers better understand.
