Java反射(JDK)与动态代理(CGLIB)详解

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
// 定义一个接口
interface MyInterface {
    void fun();
}
// 用一个类去实现这个接口
class Person implements MyInterface {
    @Override
    public void fun() {
        System.out.println("Person实现接口方法");
    }
}
// 用一个类实现InvocationHandler接口
class MyInvocationHandler<T> implements InvocationHandler {
    //InvocationHandler持有的被代理对象
    T target;
    public MyInvocationHandler(T target) {
        this.target = target;
    }
    
    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("代理执行" + method.getName() + "方法"); // 在原方法的基础上添加其他逻辑
        Object result = method.invoke(target, args); // 通过invoke方法调用原方法
        return result;
    }
}
public class Main {
    public static void main(String[] args) {
        Person person = new Person();
        InvocationHandler invocationHandler = new MyInvocationHandler<>(person);
        MyInterface proxy = (MyInterface) Proxy.newProxyInstance(Person.class.getClassLoader(),
                Person.class.getInterfaces(), invocationHandler);
        proxy.fun();
    }
}

public class Main {
    public static void main(String[] args) {
        Enhancer enhancer = new Enhancer();
        enhancer.setSuperclass(Car.class);
        enhancer.setCallback(new MethodInterceptor() {
            @Override
            public Object intercept(Object obj, Method method, Object[] args, MethodProxy methodProxy)
                    throws Throwable {
                System.out.println("before");
                Object res = methodProxy.invokeSuper(obj, args);
                System.out.println("after");
                return res;
            }
        });
        Car car = (Car) enhancer.create();
        car.print();
    }
}
class Car {
    void print() {
        System.out.println("执行原方法");
    }
}

<dependency>
    <groupId>org.sonatype.sisu.inject</groupId>
    <artifactId>cglib</artifactId>
    <version>3.1.1</version>
</dependency>