rpc 小例子

RpcFramework

 /*
 * 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.
 */
 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();
 }
 }
 });
 }

 }

RpcFramework

RpcProvider

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

RpcProvider

HelloService

 public interface HelloService {
     String hello(String name);
 }

HelloService

HelloServiceImpl

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

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

 }

HelloServiceImpl

RpcConsumer

 /*
 * 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.
 */

 /**
 * 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);
 }
 }

 }

RpcConsumer

实际上，RPC的原理其实很简单： 
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.