JDK 动态代理和 CGLIB 动态代理对比

JDK 动态代理和 CGLIB 动态代理都是实现 Spring AOP 的方式之一。

JDK 动态代理通常用于代理实现了接口的类。它是通过 java.lang.reflect.Proxy 类和 InvocationHandler 接口实现的。

CGLIB 动态代理是一个强大的高性能的代码生成库，它可以为一个类创建子类，重写其方法并添加增强的代码。CGLIB 通常用于代理没有实现接口的类。

下面是使用 JDK 动态代理和 CGLIB 动态代理的简单示例：

JDK 动态代码示例:

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
 
public class JdkDynamicProxyExample {
 
    static class MyInvocationHandler implements InvocationHandler {
        private Object target;
 
        public MyInvocationHandler(Object target) {
            this.target = target;
        }
 
        @Override
        public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
            System.out.println("Before method invocation: " + method.getName());
            Object result = method.invoke(target, args);
            System.out.println("After method invocation: " + method.getName());
            return result;
        }
    }
 
    interface MyInterface {
        void myMethod();
    }
 
    static class MyRealClass implements MyInterface {
        @Override
        public void myMethod() {
            System.out.println("Real method execution");
        }
    }
 
    public static void main(String[] args) {
        MyRealClass real = new MyRealClass();
        InvocationHandler handler = new MyInvocationHandler(real);
        MyInterface proxy = (MyInterface) Proxy.newProxyInstance(
                MyRealClass.class.getClassLoader(), 
                new Class[]{MyInterface.class}, 
                handler);
        proxy.myMethod();
    }
}

CGLIB 动态代码示例:

import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;
 
import java.lang.reflect.Method;
 
public class CglibDynamicProxyExample {
 
    static class MyMethodInterceptor implements MethodInterceptor {
        private Object target;
 
        public MyMethodInterceptor(Object target) {
            this.target = target;
        }
 
        @Override
        public Object intercept(Object obj, Method method, Object[] args, MethodProxy proxy) throws Throwable {
            System.out.println("Before method invocation: " + method.getName());
            Object result = method.invoke(target, args);
            System.out.println("After method invocation: " + method.get