How to use the Javax Interceptor API framework implementation method to intercept
Use the Javax Interceptor API framework to implement the way to intercept
Javax Interceptor API is part of the Java Ee (Enterprise Edition) specification. It provides a simple way to intercept and control method calls.Using this framework, we can add additional logic before and after the method execution.This article will introduce how to use the Javax Interceptor API framework to implement methods to intercept.
Step 1: Add dependencies
First, make sure that your project has been introduced in the Javax Interceptor API library.The specific dependency configuration can be configured according to the construction tool (such as Maven or Gradle) you use.
Step 2: Create an interceptor class
Next, we need to create a interceptor class that will implement the Internet interface in the Javax Interceptor API.The interceptor class is responsible for defining the logic to be executed before and after the method execution.
The following is the code of the interceptor class of an example:
import javax.interceptor.AroundInvoke;
import javax.interceptor.Interceptor;
import javax.interceptor.InvocationContext;
@Interceptor
public class MethodInterceptor {
@AroundInvoke
public Object intercept(InvocationContext context) throws Exception {
// Add logic before the method execution
System.out.println ("Method calls the logic before");
// Call the original method
Object result = context.proceed();
// Add logic after the method execution
System.out.println ("Logic after calling");
return result;
}
}
In the above code, we define an interceptor class `MethodInterCepTor` and mark it as the`@InternetRPTOR `to tell the Javax Interceptor API framework. It is a interceptor.
The `Internet` method uses the`@aroundinvoke` annotation mark, indicating that this method will be executed before and after the target method executes.In the `Internet` method, we can add specific logic before and after the method execution.
Step 3: Application interceptor
To apply a interceptor, we need to add `@Internetors` to the target class or method.In this way, when the target class or method is called, the interceptor will be automatically triggered.
The following is the code of the target class of an example:
import javax.interceptor.Interceptors;
@Interceptors(MethodInterceptor.class)
public class TargetClass {
public void doSomething() {
// The logic of executing the target method
System.out.println ("Performing Target Method");
}
}
In the above code, we use the method of `@interceptors` annotations to apply the interceptor` MethodInterceptor` to the method of the target class `targetClass`.
Step 4: Run code
Now, when the `dosomething` method is called, the interceptor will be automatically triggered.
Here are the complete code and execution results of a sample program:
public class Main {
public static void main(String[] args) {
TargetClass target = new TargetClass();
target.doSomething();
}
}
Results of the:
Method to call the logic before
Perform target method
Method call logic after calling
In the above code, we created an instance of `targetClass` and called its` Dosomething` method.In the console output, we can see the logic added to the interceptor that it is correctly executed before and after the method execution.
Summarize
Using the Javax Interceptor API framework, we can easily implement the method to intercept.By creating a interceptor class, we can add logic before and after the target method execute, and use the@Internetors` annotation to apply it to the target class or method.This method provides us with a flexible method to add additional behavior to the existing code.
