rpc-simple

前言

本内容来源于网络, 仅练习用

实现

1. 服务提供者

package com.example.rpc;

/**
 * 服务提供者接口定义
 *
 * @author cuishiying
 * @date 2021-01-22
 */
public interface HelloService {
    String sayHi(String name);
}

2. 服务实现

package com.example.rpc;

/**
 * 服务提供者接口实现
 *
 * @author cuishiying
 * @date 2021-01-22
 */
public class HelloServiceImpl implements HelloService {

    @Override
    public String sayHi(String name) {
        return "Hi, " + name;
    }
}

3. 服务端

package com.example.rpc;

import java.io.IOException;

/**
 * 服务端
 *
 * @author cuishiying
 * @date 2021-01-22
 */
public interface Server {
    public void stop();
    public void start() throws IOException;
    public void register(Class serviceInterface, Class impl);
    public boolean isRunning();
    public int getPort();
}

4. 服务端简单实现

package com.example.rpc;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.Method;
import java.net.InetSocketAddress;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * @author cuishiying
 * @date 2021-01-22
 */
public class ServiceCenter implements Server {
    private static ExecutorService executor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
    private static final HashMap<String, Class> serviceRegistry = new HashMap<String, Class>();
    private static boolean isRunning = false;
    private static int port;
    public ServiceCenter(int port) {
        ServiceCenter.port = port;
    }
    @Override
    public void stop() {
        isRunning = false;
        executor.shutdown();
    }
    @Override
    public void start() throws IOException {
        ServerSocket server = new ServerSocket();
        server.bind(new InetSocketAddress(port));
        System.out.println("start server");
        try {
            while (true) {
                // 1.监听客户端的TCP连接，接到TCP连接后将其封装成task，由线程池执行
                executor.execute(new ServiceTask(server.accept()));
            }
        } finally {
            server.close();
        }
    }
    @Override
    public void register(Class serviceInterface, Class impl) {
        serviceRegistry.put(serviceInterface.getName(), impl);
    }
    @Override
    public boolean isRunning() {
        return isRunning;
    }
    @Override
    public int getPort() {
        return port;
    }
    private static class ServiceTask implements Runnable {
        Socket clent = null;
        public ServiceTask(Socket client) {
            this.clent = client;
        }
        @Override
        public void run() {
            ObjectInputStream input = null;
            ObjectOutputStream output = null;
            try {
                // 2.将客户端发送的码流反序列化成对象，反射调用服务实现者，获取执行结果
                input = new ObjectInputStream(clent.getInputStream());
                String serviceName = input.readUTF();
                String methodName = input.readUTF();
                Class<?>[] parameterTypes = (Class<?>[]) input.readObject();
                Object[] arguments = (Object[]) input.readObject();
                Class serviceClass = serviceRegistry.get(serviceName);
                if (serviceClass == null) {
                    throw new ClassNotFoundException(serviceName + " not found");
                }
                Method method = serviceClass.getMethod(methodName, parameterTypes);
                Object result = method.invoke(serviceClass.newInstance(), arguments);
                // 3.将执行结果反序列化，通过socket发送给客户端
                output = new ObjectOutputStream(clent.getOutputStream());
                output.writeObject(result);
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (output != null) {
                    try {
                        output.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (input != null) {
                    try {
                        input.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
                if (clent != null) {
                    try {
                        clent.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }
}

5. 客户端

package com.example.rpc;

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.InetSocketAddress;
import java.net.Socket;

/**
 * 客户端
 *
 * @author cuishiying
 * @date 2021-01-22
 */
public class RPCClient<T> {
    public static <T> T getRemoteProxyObj(final Class<?> serviceInterface, final InetSocketAddress addr) {
        // 1.将本地的接口调用转换成JDK的动态代理，在动态代理中实现接口的远程调用
        return (T) Proxy.newProxyInstance(serviceInterface.getClassLoader(), new Class<?>[]{serviceInterface},
                new InvocationHandler() {
                    @Override
                    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                        Socket socket = null;
                        ObjectOutputStream output = null;
                        ObjectInputStream input = null;
                        try {
                            // 2.创建Socket客户端，根据指定地址连接远程服务提供者
                            socket = new Socket();
                            socket.connect(addr);
                            // 3.将远程服务调用所需的接口类、方法名、参数列表等编码后发送给服务提供者
                            output = new ObjectOutputStream(socket.getOutputStream());
                            output.writeUTF(serviceInterface.getName());
                            output.writeUTF(method.getName());
                            output.writeObject(method.getParameterTypes());
                            output.writeObject(args);
                            // 4.同步阻塞等待服务器返回应答，获取应答后返回
                            input = new ObjectInputStream(socket.getInputStream());
                            return input.readObject();
                        } finally {
                            if (socket != null) {
                                socket.close();
                            }
                            if (output != null) {
                                output.close();
                            }
                            if (input != null) {
                                input.close();
                            }
                        }
                    }
                });
    }
}

6. 测试

package com.example.rpc;

import java.io.IOException;
import java.net.InetSocketAddress;

/**
 * 输出:
 *
 * start server
 * Hi, 当我遇上你
 *
 * @author cuishiying
 * @date 2021-01-22
 */
public class RPCTest {
    public static void main(String[] args) throws IOException {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Server serviceServer = new ServiceCenter(8088);
                    serviceServer.register(HelloService.class, HelloServiceImpl.class);
                    serviceServer.start();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
        HelloService service = RPCClient.getRemoteProxyObj(HelloService.class, new InetSocketAddress("localhost", 8088));
        System.out.println(service.sayHi("当我遇上你"));
    }
}

参考

• https://zhuanlan.zhihu.com/p/89331645

最后

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