RPC框架几行代码就够了

转于自己在公司的Blog：
http://pt.alibaba-inc.com/wp/experience_1330/simple-rpc-framework.html

因为要给百技上实训课，让新同学们自行实现一个简易RPC框架，在准备PPT时，就想写个示例，发现原来一个RPC框架只要一个类，10来分钟就可以写完了，虽然简陋，也晒晒：

/*
 * Copyright 2011 Alibaba.com All right reserved. This software is the
 * confidential and proprietary information of Alibaba.com ("Confidential
 * Information"). You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Alibaba.com.
 */
package com.alibaba.study.rpc.framework;

import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * RpcFramework
 * 
 * @author william.liangf
 */
public class RpcFramework {

    /**
     * 暴露服务
     * 
     * @param service 服务实现
     * @param port 服务端口
     * @throws Exception
     */
    public static void export(final Object service, int port) throws Exception {
        if (service == null)
            throw new IllegalArgumentException("service instance == null");
        if (port <= 0 || port > 65535)
            throw new IllegalArgumentException("Invalid port " + port);
        System.out.println("Export service " + service.getClass().getName() + " on port " + port);
        ServerSocket server = new ServerSocket(port);
        for(;;) {
            try {
                final Socket socket = server.accept();
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            try {
                                ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
                                try {
                                    String methodName = input.readUTF();
                                    Class<?>[] parameterTypes = (Class<?>[])input.readObject();
                                    Object[] arguments = (Object[])input.readObject();
                                    ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
                                    try {
                                        Method method = service.getClass().getMethod(methodName, parameterTypes);
                                        Object result = method.invoke(service, arguments);
                                        output.writeObject(result);
                                    } catch (Throwable t) {
                                        output.writeObject(t);
                                    } finally {
                                        output.close();
                                    }
                                } finally {
                                    input.close();
                                }
                            } finally {
                                socket.close();
                            }
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                    }
                }).start();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * 引用服务
     * 
     * @param <T> 接口泛型
     * @param interfaceClass 接口类型
     * @param host 服务器主机名
     * @param port 服务器端口
     * @return 远程服务
     * @throws Exception
     */
    @SuppressWarnings("unchecked")
    public static <T> T refer(final Class<T> interfaceClass, final String host, final int port) throws Exception {
        if (interfaceClass == null)
            throw new IllegalArgumentException("Interface class == null");
        if (! interfaceClass.isInterface())
            throw new IllegalArgumentException("The " + interfaceClass.getName() + " must be interface class!");
        if (host == null || host.length() == 0)
            throw new IllegalArgumentException("Host == null!");
        if (port <= 0 || port > 65535)
            throw new IllegalArgumentException("Invalid port " + port);
        System.out.println("Get remote service " + interfaceClass.getName() + " from server " + host + ":" + port);
        return (T) Proxy.newProxyInstance(interfaceClass.getClassLoader(), new Class<?>[] {interfaceClass}, new InvocationHandler() {
            public Object invoke(Object proxy, Method method, Object[] arguments) throws Throwable {
                Socket socket = new Socket(host, port);
                try {
                    ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
                    try {
                        output.writeUTF(method.getName());
                        output.writeObject(method.getParameterTypes());
                        output.writeObject(arguments);
                        ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
                        try {
                            Object result = input.readObject();
                            if (result instanceof Throwable) {
                                throw (Throwable) result;
                            }
                            return result;
                        } finally {
                            input.close();
                        }
                    } finally {
                        output.close();
                    }
                } finally {
                    socket.close();
                }
            }
        });
    }

}

用起来也像模像样：

(1) 定义服务接口

/*
 * Copyright 2011 Alibaba.com All right reserved. This software is the
 * confidential and proprietary information of Alibaba.com ("Confidential
 * Information"). You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Alibaba.com.
 */
package com.alibaba.study.rpc.test;

/**
 * HelloService
 * 
 * @author william.liangf
 */
public interface HelloService {

    String hello(String name);

}

(2) 实现服务

/*
 * Copyright 2011 Alibaba.com All right reserved. This software is the
 * confidential and proprietary information of Alibaba.com ("Confidential
 * Information"). You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Alibaba.com.
 */
package com.alibaba.study.rpc.test;

/**
 * HelloServiceImpl
 * 
 * @author william.liangf
 */
public class HelloServiceImpl implements HelloService {

    public String hello(String name) {
        return "Hello " + name;
    }

}

(3) 暴露服务

/*
 * Copyright 2011 Alibaba.com All right reserved. This software is the
 * confidential and proprietary information of Alibaba.com ("Confidential
 * Information"). You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Alibaba.com.
 */
package com.alibaba.study.rpc.test;

import com.alibaba.study.rpc.framework.RpcFramework;

/**
 * RpcProvider
 * 
 * @author william.liangf
 */
public class RpcProvider {

    public static void main(String[] args) throws Exception {
        HelloService service = new HelloServiceImpl();
        RpcFramework.export(service, 1234);
    }

}

(4) 引用服务

/*
 * Copyright 2011 Alibaba.com All right reserved. This software is the
 * confidential and proprietary information of Alibaba.com ("Confidential
 * Information"). You shall not disclose such Confidential Information and shall
 * use it only in accordance with the terms of the license agreement you entered
 * into with Alibaba.com.
 */
package com.alibaba.study.rpc.test;

import com.alibaba.study.rpc.framework.RpcFramework;

/**
 * RpcConsumer
 * 
 * @author william.liangf
 */
public class RpcConsumer {
    
    public static void main(String[] args) throws Exception {
        HelloService service = RpcFramework.refer(HelloService.class, "127.0.0.1", 1234);
        for (int i = 0; i < Integer.MAX_VALUE; i ++) {
            String hello = service.hello("World" + i);
            System.out.println(hello);
            Thread.sleep(1000);
        }
    }
    
}

评论

13 楼 evans_he 2014-06-05  

核心就是socket和动态代理

12 楼 mojianpo 2014-04-09  

demo 写的很不错，支持支持支持

11 楼 leixbo 2014-02-28  

jyjava 写道

说白了就是Socket编程，传输Object

正解

10 楼 id.alex 2013-11-13  

有个地方说错了, LZ的 RPC 例子是短连接,在调用方法时才创建连接,

9 楼 id.alex 2013-11-13  

yymn_love 写道

Hi，我在这个方面比较无知，我只是觉得RPC应该是远程调用的，就像webservice。我的疑问是：
1 RPC是否是类似webservice的服务？
  (如果是或者类似的话看第二个，否则就不要看了)
2 服务器端有代码，是提供其他的客户端访问的。那么肯定客户端不是和服务器是同一套代码，客户端肯定不能使用服务器的类了。这个RPC是怎么工作的？


希望得到您的回复。谢谢！

第一个问题,
    是类似的用法
第二个问题.
    服务器端有 Interface 和 Implement 类,
    客户端只有 Interface .
原理,
服务器启动了一个线程监听 Socket 端口,
有Socket访问了, 反序列化解析出
调用哪个Service 哪个 方法, 以及传入的 参数,
再用Socket 写回去.

客户端 利用 Jdk 的Proxy 生成了一个代理类,
在创建 Proxy 时建立与服务器的Socket连接.
调用 Proxy 的方法时, 向服务器发送数据, 等待结果返回.

8 楼 id.alex 2013-11-13  

rxin2009 写道

能帮忙解释下
HelloService service = RpcFramework.refer(HelloService.class, "127.0.0.1", 1234);  中的service是怎么生成的吗(看了下代码，在实例HelloServiceImpl生成前是没有socket连接的)？

RpcFramework  第100行

return (T) Proxy.newProxyInstance(interfaceClass.getClassLoader(), new Class<?>[] {interfaceClass}, new InvocationHandler() {... ...})

7 楼 chenfuzhao 2013-08-18  

有学习研究精神很好，但希望能把RPC的真正概念搞清楚！！！

6 楼 rxin2009 2013-05-27  

能帮忙解释下
HelloService service = RpcFramework.refer(HelloService.class, "127.0.0.1", 1234);  中的service是怎么生成的吗(看了下代码，在实例HelloServiceImpl生成前是没有socket连接的)？

5 楼 guojch 2013-04-29  

Very simple but very useful to understand the RPC working principle.Thanks for sharing!

4 楼 jyjava 2013-01-26  

说白了就是Socket编程，传输Object

3 楼 melin 2011-12-19  

this is great!!!

2 楼 yymn_love 2011-10-22  

Hi，我在这个方面比较无知，我只是觉得RPC应该是远程调用的，就像webservice。我的疑问是：
1 RPC是否是类似webservice的服务？
  (如果是或者类似的话看第二个，否则就不要看了)
2 服务器端有代码，是提供其他的客户端访问的。那么肯定客户端不是和服务器是同一套代码，客户端肯定不能使用服务器的类了。这个RPC是怎么工作的？


希望得到您的回复。谢谢！

1 楼 liyebing 2011-09-16  

好！学习了。。希望看到您更多更精彩的分享