Exploring the technical principles of the NANNING framework in the Java class library
Exploring the technical principles of the NANNING framework in the Java class library
Nanning is a powerful and easy -to -use Java class library for dynamic proxy and AOP (facing cut -faced programming).This article will explore the technical principles of the Nanning framework and how to use and configure it.
1. What is a dynamic proxy
Dynamic proxy is a technology that creates proxy objects during running.It allows to enhance or modify the behavior of objects by adding additional logic without modifying the existing code.Dynamic proxy is usually used to implement functions such as log records, performance monitoring, and transaction management.
2. What is AOP (facing cut -oriented programming)
AOP is a programming idea to separate the horizontal section focus (such as logging, security, error treatment, etc.) from the core business logic.Using AOP, you can modify these horizontal sectors and apply them to the specific method or code blocks of the application when needed.
3. The technical principle of the Nanning framework
The Nanning framework implements its functions by using dynamic proxy and AOP principles.It provides basic proxy mode and higher -level AOP support.
1. Basic proxy mode:
Nanning uses Java's dynamic agency mechanism to create agent objects.It dynamically generates a proxy class that realizes the specified interface and connects the proxy class to the actual object during runtime.In this way, when we call the proxy object method, the method of the actual object is also called.
Below is an example code of a basic proxy mode:
public interface UserService {
void saveUser(String username);
}
public class UserServiceImpl implements UserService {
public void saveUser(String username) {
System.out.println("Saving user: " + username);
}
}
public class UserServiceProxy implements InvocationHandler {
private Object target;
public UserServiceProxy(Object target) {
this.target = target;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
System.out.println("Before method execution");
Object result = method.invoke(target, args);
System.out.println("After method execution");
return result;
}
}
public class Main {
public static void main(String[] args) {
UserService userService = new UserServiceImpl();
UserService proxy = (UserService) Proxy.newProxyInstance(
userService.getClass().getClassLoader(),
userService.getClass().getInterfaces(),
new UserServiceProxy(userService));
proxy.saveUser("John Doe");
}
}
In the above example, we define an UserService interface and its implementation of UserServiceIMPL.Then, we created an agent UserServiceProxy to implement the InvoCationHandler interface.In the Invoke method, we can add additional logic, such as printing logs before and after the method execution.In the main class, we use Proxy.NewProxyinstance Method to create the proxy object of the userService interface and connect it to the actual object userService.When we call the Saveuser method of the proxy object, we will execute the INVOKE method in the proxy object, and then call the actual object method.In this way, we can add custom logic before and after the execution method.
2. AOP support:
In addition to the basic proxy mode, Nanning also provides more powerful AOP support.It allows the use of annotations and XML configurations to define cutting and notifications.
The following is an AOP example code using Nanning:
@Aspect
public class LoggingAspect {
@Before("execution(* com.example.service.*.*(..))")
public void beforeMethodExecution(JoinPoint joinPoint) {
System.out.println("Before method execution: " + joinPoint.getSignature().getName());
}
@After("execution(* com.example.service.*.*(..))")
public void afterMethodExecution(JoinPoint joinPoint) {
System.out.println("After method execution: " + joinPoint.getSignature().getName());
}
}
public class UserService {
public void saveUser(String username) {
System.out.println("Saving user: " + username);
}
}
public class Main {
public static void main(String[] args) {
ApplicationContext context = new ClassPathXmlApplicationContext("applicationContext.xml");
UserService userService = (UserService) context.getBean("userService");
userService.saveUser("John Doe");
}
}
In the above example, we define a cut Loggingaspect, and use @Beface and @aver annotations to define two notices.@Before Note indicates that the notification is called before the method execution, and@AFTER Note indicates that the notification is called after the method is executed.The Execution expression in the annotation specifies the entry point, that is, the method that needs to be enhanced.
In the Main class, we use ApplicationContext to load the configuration file ApplicationContext.xml and get the bean named Userservice.Then, when we call the SaveUser method of UserService, it will trigger the notification in the cut surface loggingaspect.The notice will print the log before and after the method execution.
Fourth, configure the Nanning framework
To use the Nanning framework, you need to add it to the dependency item of the project.You can add the following dependencies to configure files or build tools:
<dependency>
<groupId>org.codehaus.nanning</groupId>
<artifactId>nanning-lib</artifactId>
<version>0.8.6</version>
</dependency>
Once the dependencies are added, the functions provided by the Nanning framework can be used in the code.As shown in the example code above, the proxy object can be created and applied to the AOP surface.
Summarize:
This article introduces the technology principle of the Nanning framework. It is a powerful Java class library for realizing dynamic proxy and AOP.By using dynamic proxy and AOP, Nanning can enhance or modify the object during runtime.Using the Nanning framework, we can easily implement functions such as log records, performance monitoring, and transaction management.
