一个RPC的demo

从下面的例子中可以看到，Consumer(client)的代码中引用了Provider部分的class，本例中是

com.provider.EchoServiceImpl和com.provider.EchoService

即这些class在Consumer(client)和Provider(server)都需要部署

Provider:

package com.provider;

public interface EchoService {
    String echo(String msg);
}

package com.provider;

public class EchoServiceImpl implements EchoService {
    @Override
    public String echo(String msg) {
        return msg != null ? msg + "-->I am OK." : " pass null.";
    }
}

package com.provider;

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.concurrent.Executor;
import java.util.concurrent.Executors;

public class RpcProvider {
    private static Executor executor = Executors.newFixedThreadPool(20);

    public static void provide(String host, int port) throws IOException {
        ServerSocket serverSocket = new ServerSocket();
        serverSocket.bind(new InetSocketAddress(host, port));
        try {
            while (true) {
                System.out.println("one input coming");
                executor.execute(new ProviderTask(serverSocket.accept()));
                System.out.println("execute one input");
            }
        } finally {
            serverSocket.close();
        }

    }

    private static class ProviderTask implements Runnable {
        private Socket socket;

        public ProviderTask(Socket socket) {
            this.socket = socket;
        }

        @Override
        public void run() {
            ObjectInputStream inputStream = null;
            ObjectOutputStream outputStream = null;
            try {
                inputStream = new ObjectInputStream(socket.getInputStream());
                String className = inputStream.readUTF();
                Class<?> service = Class.forName(className);
                String methodName = inputStream.readUTF();
                Class<?>[] parameterTypes = (Class<?>[]) inputStream.readObject();
                Object[] arguments = (Object[]) inputStream.readObject();
                Method method = service.getMethod(methodName, parameterTypes);
                Object result = method.invoke(service.newInstance(), arguments);
                outputStream = new ObjectOutputStream(socket.getOutputStream());
                outputStream.writeObject(result);
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                close(inputStream);
                close(outputStream);
                close(socket);
            }
        }

    }

    public static void close(AutoCloseable closeable) {
        if (closeable != null) {
            try {
                closeable.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}

package com.provider;

import java.io.IOException;

public class ProviderMain {
    public static void main(String[] args) {
        try {
            RpcProvider.provide("localhost", 8088);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Consumer:

package com.consumer;

import com.provider.RpcProvider;

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;

public class RpcConsumer {

    public Object consume(Class<?> echoServiceClass, InetSocketAddress socketAddress) {
        return Proxy.newProxyInstance(echoServiceClass.getClassLoader(), new Class<?>[]{echoServiceClass.getInterfaces()[0]}, new InvocationHandler() {
            @Override
            public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                Socket socket = null;
                ObjectOutputStream outputStream = null;
                ObjectInputStream inputStream = null;
                try {
                    socket = new Socket();
                    socket.connect(socketAddress);
                    outputStream = new ObjectOutputStream(socket.getOutputStream());
                    outputStream.writeUTF(echoServiceClass.getName());
                    outputStream.writeUTF(method.getName());
                    outputStream.writeObject(method.getParameterTypes());
                    outputStream.writeObject(args);
                    inputStream = new ObjectInputStream(socket.getInputStream());
                    return inputStream.readObject();
                } finally {
                    RpcProvider.close(outputStream);
                    RpcProvider.close(inputStream);
                    RpcProvider.close(socket);
                }
            }
        });
    }

}

package com.consumer;

import com.provider.EchoService;
import com.provider.EchoServiceImpl;

import java.net.InetSocketAddress;

public class ConsumerMain {
    public static void main(String[] args) {
        RpcConsumer rpcConsumer = new RpcConsumer();
        EchoService echoService = (EchoService) rpcConsumer.consume(EchoServiceImpl.class, new InetSocketAddress("localhost", 8088));
        System.out.println(echoService.echo(ConsumerMain.class.getCanonicalName()));
    }

}