背景：

发现公司几个运行10年的游戏，用的竟然是rmi，而我只听说过dubbo 和 基于netty的rpc，于是就补充了下rmi。

其次，是最近对于跨服的思考，如何避免回调也需要用同步写法，rmi比较适合。

1)api

游戏服之间的交互 // 必须抛出RemoteException异常

package com.example.testsb.testrmi.api;import com.example.testsb.testrmi.common.CSLogin;
import com.example.testsb.testrmi.common.SCLogin;import java.rmi.Remote;
import java.rmi.RemoteException;public interface IGameService extends Remote {// 简单的rpc接口String hello(String str) throws RemoteException;// 请求和返回都是复杂对象的rpc接口SCLogin login(CSLogin req) throws RemoteException;
}

2)通用部分

package com.example.testsb.testrmi.common;public class Constant {public final static int GAME_SERVICE_PORT = 6000;public final static String GAME_SERVICE_URL = String.format("rmi://localhost:%d/IGameService", GAME_SERVICE_PORT);
}

复杂协议 // 必须实现:Serializable接口

package com.example.testsb.testrmi.common;import lombok.Data;import java.io.Serializable;@Data
public class CSLogin implements Serializable {private static final long serialVersionUID = 1L;private String name;private String password;
}

package com.example.testsb.testrmi.common;import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;import java.io.Serializable;@Data
@AllArgsConstructor
@NoArgsConstructor
public class SCLogin implements Serializable {private static final long serialVersionUID = 1L;private long uid;
}

3)服务端

package com.example.testsb.testrmi.server;import com.example.testsb.testrmi.api.IGameService;
import com.example.testsb.testrmi.common.Constant;
import com.example.testsb.testrmi.server.impl.GameServiceImpl;import java.net.MalformedURLException;
import java.rmi.Naming;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;public class Server {public static void main(String[] args) throws RemoteException, MalformedURLException {IGameService gameService = new GameServiceImpl();LocateRegistry.createRegistry(Constant.GAME_SERVICE_PORT);Naming.rebind(Constant.GAME_SERVICE_URL, gameService);}
}/*
[2024-03-19 07:14:13.601] [RMI TCP Connection(4)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:13.602] [RMI TCP Connection(4)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:13.603] [RMI TCP Connection(4)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:13.604] [RMI TCP Connection(4)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:29.975] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:29.982] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:29.984] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:29.986] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:29.988] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:29.993] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:29.995] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:29.997] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:30.000] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123
[2024-03-19 07:14:30.002] [RMI TCP Connection(6)-192.168.152.1] [GameServiceImpl.java:24] ([INFO][com.example.testsb.testrmi.server.impl.GameServiceImpl] 1000 123*/

实现

package com.example.testsb.testrmi.server.impl;import com.example.testsb.testrmi.api.IGameService;
import com.example.testsb.testrmi.common.CSLogin;
import com.example.testsb.testrmi.common.SCLogin;
import lombok.extern.slf4j.Slf4j;import java.rmi.RemoteException;
import java.rmi.server.UnicastRemoteObject;@Slf4j
public class GameServiceImpl extends UnicastRemoteObject implements IGameService {public GameServiceImpl() throws RemoteException {super();}@Overridepublic String hello(String str) {return str + "_world";}@Overridepublic SCLogin login(CSLogin req) {log.info("{} {}", req.getName().length(), req.getPassword());return new SCLogin(1);}
}

4)客户端

package com.example.testsb.testrmi.client;import com.example.testsb.testrmi.api.IGameService;
import com.example.testsb.testrmi.common.CSLogin;
import com.example.testsb.testrmi.common.Constant;
import com.example.testsb.testrmi.common.SCLogin;
import lombok.extern.slf4j.Slf4j;import java.net.MalformedURLException;
import java.rmi.Naming;
import java.rmi.NotBoundException;
import java.rmi.RemoteException;@Slf4j
public class Client {public static void main(String[] args) throws MalformedURLException, NotBoundException, RemoteException {IGameService gameService = (IGameService) Naming.lookup(Constant.GAME_SERVICE_URL);String name = "";for (int i = 0; i < 100; i++) {name += "123456789a";}for (int j = 0; j < 10; j++) {// 测试helloString hello = gameService.hello("hello");log.info("{}", hello);// 测试登录接口CSLogin csLogin = new CSLogin();csLogin.setName(name);csLogin.setPassword("123");SCLogin login = gameService.login(csLogin);log.info("{}", login);}}
}/*
[2024-03-19 07:14:29.970] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:29.977] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)
[2024-03-19 07:14:29.981] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:29.982] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)
[2024-03-19 07:14:29.983] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:29.984] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)
[2024-03-19 07:14:29.985] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:29.986] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)
[2024-03-19 07:14:29.987] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:29.988] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)
[2024-03-19 07:14:29.993] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:29.994] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)
[2024-03-19 07:14:29.995] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:29.996] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)
[2024-03-19 07:14:29.997] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:29.998] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)
[2024-03-19 07:14:29.999] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:30.000] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)
[2024-03-19 07:14:30.001] [main] [Client.java:26] ([INFO][com.example.testsb.testrmi.client.Client] hello_world
[2024-03-19 07:14:30.003] [main] [Client.java:33] ([INFO][com.example.testsb.testrmi.client.Client] SCLogin(uid=1)*/

总结：

1.rmi可以看出来非常简单。

2.基于java的序列化和反序列化。

3.已解决粘包问题。