RPC框架 客户端 声明一个接口 ，就可以发起远程调用
动态代理 动态生成类

java.lang.reflect.Proxy
public static Object newProxyInstance(ClassLoader loader,Class< ?>[] interfaces,InvocationHandler h)
 
InvocationHandler
public Object invoke(Object proxy, Method method, Object[] args)throws Throwable
                                        
private static interface Hello{
		String sayHello(String name);
}
实现 InvocationHandler invoke 方法 ，动态创建代理类




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

public class InvocationHandlerSimpleTest {

    public static void main(String[] args) throws Exception {
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        Class<?>[] interfaces = new Class[] {Hello.class};
        InvocationHandler h = new MyInvocationHandler();       
        Hello hello = (Hello)Proxy.newProxyInstance(loader, interfaces, h);		
        System.out.println(hello.sayHello("dyyx"));
        System.out.println(hello.sayHello("tiger"));
    }
	
    private static class MyInvocationHandler implements InvocationHandler{		
        public Object invoke(Object proxy, Method method, Object[] args)throws Throwable{		     
            if("sayHello".equals(method.getName())) {
                return "hello,"+args[0];
             }			 
             throw new Exception("not support method,"+method.getName());
        }
    }
    private static interface Hello{
        String sayHello(String name);
    }
}

https://gitee.com/dyyx/hellocode/blob/master/src/proxy/InvocationHandlerSimpleTest.java

这个例子里，没有被代理对象
invoke 方法里也做了简化 ， 没有 对 hashCode toString 等方法的处理

更完整的例子
https://gitee.com/dyyx/hellocode/blob/master/src/proxy/InvocationHandlerTest.java


 

再来一个有被代理对象的 ， 调用前后打印日志



Hello realObject = new HelloImpl();
ClassLoader loader =  realObject.getClass().getClassLoader();
Class<?>[] interfaces = realObject.getClass().getInterfaces();
InvocationHandler h = new MyInvocationHandler(realObject);      
Hello hello = (Hello)Proxy.newProxyInstance(loader, interfaces, h);		
System.out.println(hello.sayHello("dyyx"));

private static class MyInvocationHandler implements InvocationHandler{	
    // 被代理对象 实际的对象
    private final Hello realObject;
    public MyInvocationHandler(Hello realObject) {
        this.realObject = realObject;	 
    }
		 
    public Object invoke(Object proxy, Method method, Object[] args)throws Throwable{		     
        if("sayHello".equals(method.getName())) {
            System.out.println("invoke start,name="+args[0]);
            Object result = method.invoke(realObject, args);
            System.out.println("invoke done,result="+result);		 
            return result;
         }			 
         throw new Exception("not support method,"+method.getName());
    }
}


https://gitee.com/dyyx/hellocode/blob/master/src/proxy/InvocationHandlerLogTest.java




更完善的例子，rpc 客户端 动态生成代理类                     
         
https://gitee.com/dyyx/nettyrpc/blob/master/src/main/java/com/dyyx/nettyrpc/client/proxy/ObjectProxy.java
                                                                                  

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