CGLIB FULL framework application instance: Details and skills to implement AOP programming in the Java class library

CGLIB is a powerful bytecode operating library that implements the programming mode of AOP (facing surface programming) in the Java class library.It allows developers to perform dynamic proxy of the Java class at runtime to achieve various functions, such as method interception, attribute interception and event monitoring.In this article, we will explore the application instance of the CGLIB FULL framework and introduce some details and techniques of AOP programming when using CGLIB for AOP programming. 1. Introduction to CGLIB CGLIB is a byte code operating library based on ASM (open source Java bytecode editing and analysis framework), which allows us to generate and modify the byte code of the Java class during runtime.Compared to the Java native dynamic proxy mechanism (interface -based proxy), CGLIB does not require the proxy class implementation interface. It can represent arbitrary Java classes, including those classes that have not implemented interfaces. Second, CGLIB FULL framework The CGLIB FULL framework is an extension of the CGLIB library. It provides more functions and flexibility, which can easily achieve AOP programming.Below is an example of the CGLIB FULL framework: 1. Create a target class First of all, we need to create a target class, that is, the class that needs to be agent.For example, we create a class called Userservice and define a method called Saveuser: public class UserService { public void saveUser(String userName) { System.out.println("Saving user: " + userName); } } 2. Create an interceptor Next, we need to create an interceptor class to perform some additional logic before and after the target class.For example, we create a class called UserInterceptor: public class UserInterceptor implements MethodInterceptor { @Override public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable { System.out.println("Before method: " + method.getName()); // Add additional logic before and after the target method Object result = proxy.invokeSuper(obj, args); System.out.println("After method: " + method.getName()); return result; } } 3. Create proxy classes Using the CGLIB FULL framework, we can create the proxy class through the following steps: public class Main { public static void main(String[] args) { // Create an enhancer object Enhancer enhancer = new Enhancer(); // Set the parent class of the target class, that is, the class that needs to be represented enhancer.setSuperclass(UserService.class); // Set the interceptor enhancer.setCallback(new UserInterceptor()); // Create proxy classes UserService proxy = (UserService) enhancer.create(); // Call the method of the proxy class proxy.saveUser("Alice"); } } 4. Run results When we run the above code, the following results will be output: Before method: saveUser Saving user: Alice After method: saveUser It can be seen from the output results that the interceptor printed the information of "BeFore Method: Saveuser" and "After Method: Saveuse" and execute the target method. Third, the details and skills of the CGLIB FULL framework application When using the CGLIB FULL framework for AOP programming, there are some details and skills to pay attention: 1. The CGLIB FULL framework is a dynamic proxy through bytecode operation. Therefore, it is slightly inferior to Java's native dynamic proxy mechanism, but it is better than reflected dynamic agents. 2. The CGLIB FULL framework can only be represented by non -final and non -final methods. 3. The CGLIB FULL framework cannot represent Static, Private, and Final methods. In summary, the CGLIB FULL framework is a powerful bytecode operating library that implements the programming mode of AOP programming in the Java class library.By using the CGLIB FULL framework, developers can more conveniently achieve dynamic proxy and add additional logic before and after the goal method execution.When using the CGLIB FULL framework, you need to pay attention to some details and skills to ensure correctly AOP programming.