无题

package tmp;

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

public class test {


    public interface Hello {
        void morning(String name);
    }
    public static class HelloWorld implements Hello {
        public void morning(String name) {
            System.out.println("Good morning, " + name);
        }
    }
    public static void main(String[] args) throws Exception{
        InvocationHandler handler = new InvocationHandler() {
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                System.out.println(method);
                if (method.getName().equals("morning")) {
                    System.out.println("Good morning, " + args[0]);
                    System.out.println("proxy.getClass().getName()");
                }
                return null;
            }
        };
        Hello hello = (Hello) java.lang.reflect.Proxy.newProxyInstance(
                Hello.class.getClassLoader(), // 传入ClassLoader
                new Class[]{Hello.class}, // 传入要实现的接口
                handler); // 传入处理调用方法的InvocationHandler
        hello.morning("Bob");
    }
    
}

实际是是JVM在运行的时候创建的class字节码并加载

public class HelloDynamicProxy implements Hello {
    InvocationHandler handler;
    public HelloDynamicProxy(InvocationHandler handler) {
        this.handler = handler;
    }
    public void morning(String name) {
        handler.invoke(
           this,
           Hello.class.getMethod("morning", String.class),
           new Object[] { name });
    }
}