Analysis of the technical principles of Nanning Framework in Java Class Libraries
Analysis of the technical principles of the nanning framework in the Java class library
Nanning is a lightweight, Java-based AOP (Aspect-Oriented Programming) framework, which can be used to achieve horizontal sectaries (Cross-Cutting Concerss) with the characteristics of statement programming and modular design.Separation.This article will analyze the technical principles of the Nanning framework in detail and provide the necessary programming code and related configuration.
The core technical principles of the Nanning framework are based on dynamic agents.Dynamic proxy refers to replacing the original object by creating an agent object during runtime, and the calling method of intercepting methods in the proxy object, so as to achieve the separation of horizontal cutting attention points.
First, we need to clarify the two core concepts: aspect (aspect) and pointcut.The cut surface is the implementation of cross -cut logic. It defines one or more interceptors to perform specific logic when the target method is called before, after calling, or abnormal throwing.Cut the point is a set of target methods, which defines which methods will be intercepted by the cut surface.
Below is a simple example of using the Nanning framework:
public interface HelloService {
void sayHello(String name);
}
public class HelloServiceImpl implements HelloService {
public void sayHello(String name) {
System.out.println("Hello, " + name);
}
}
public class LoggingInterceptor implements Interceptor {
public Object invoke(MethodInvocation invocation) throws Throwable {
System.out.println("Before method execution");
Object result = invocation.proceed();
System.out.println("After method execution");
return result;
}
}
public class Main {
public static void main(String[] args) {
HelloService helloService = (HelloService) BasicProxyFactory.createProxy(new HelloServiceImpl(), new LoggingInterceptor());
helloService.sayHello("Nanning");
}
}
In the above code, we first defined a service interface `Helloservice` and realized its specific implementation class` HelloserviceIMPL`.Then, we created a interceptor `LoggingInterceptor`, which output log information before and after the target method calls.Finally, in the `main` class, we use the method of` BasicProxyfactory.createProxy () `to create an agent object, and to pass the target object and interceptor object as parameters.By calling the `Sayhello () method of the proxy object, we can trigger the logic of the interceptor.
In the Nanning framework, the method of `BasicProxyfactory.createProxy () is the key to realizing dynamic proxy.It creates an agent object based on the target object and interceptor object, and uses bytecode technology to dynamically generate the byte code of the proxy class.
In addition, we also need to configure related configuration files of the Nanning framework.In the Java library, the configuration file in XML format is usually used.The following is an example configuration file `nanning.xml`:
<?xml version="1.0" encoding="UTF-8"?>
<nanning-config>
<interceptors>
<interceptor class="com.example.LoggingInterceptor"/>
</interceptors>
<pointcuts>
<pointcut class="com.example.HelloService" method="sayHello"/>
</pointcuts>
</nanning-config>
In the configuration file, we first define the class path of the interceptor `Logging:Then, we defined a cut point, specifying the target class `HelloService` and the method that needs to be intercepted.
Through the above configuration files, we can load and use the Nanning framework during runtime.The specific loading and configuration process can be implemented through the following code:
public class NanningConfigurator {
public static void configure(String configFile) {
URL url = NanningConfigurator.class.getClassLoader().getResource(configFile);
NanningContext context = new ByteArrayInputStream(url.openStream());
NanningContext.getInstance().configure(context);
}
}
public class Main {
public static void main(String[] args) {
NanningConfigurator.configure("nanning.xml");
HelloService helloService = (HelloService) BasicProxyFactory.createProxy(new HelloServiceImpl());
helloService.sayHello("Nanning");
}
}
In the above code, we created a `nanningconfigurator` class to load and configure the Nanning framework.In the `main ()" method of the `Main` class, we first call the` nanningconfigurator.configure () method to load the configuration file and instantiate the proxy object.
By understanding the technical principles and usage methods of the Nanning framework, we can better understand and apply this AOP framework based on the Java -class library, thereby improving the maintenance and flexibility of the software system.
I hope this article will help you understand the technical principles of the nanning framework!
