很简单Java动态代理实现

public interface Base {
    void baseMethod();
}

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;

public class CustomHandler<T> implements InvocationHandler {
    T target;

    public CustomHandler(T target){
        this.target = target;
    }

    @Override
    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        System.out.println("start...");
        Object result = method.invoke(target, args);
        System.out.println("end...");
        return result;
    }
}

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Proxy;

public class ProxyTest {

    public static void main(String[] args) {
        Base base = () -> System.out.println("in hand...");
        InvocationHandler handler = new CustomHandler<>(base);
　　　　　// 生成代理对象
        Base baseProxy = (Base)Proxy.newProxyInstance(ProxyTest.class.getClassLoader(), new Class[]{Base.class}, handler);
        baseProxy.baseMethod();
    }
}

start...
in hand...
end...

Process finished with exit code 0