java写RPC客户端服务端

Java可以使用多种方式来实现RPC客户端服务端，比如使用Netty、Java RMI、Apache Thrift等。

以下是使用Netty实现RPC客户端服务端的示例代码：

服务端代码：

public class RpcServer {
    public void start(int port) throws Exception {
        EventLoopGroup bossGroup = new NioEventLoopGroup();
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(bossGroup, workerGroup)
                     .channel(NioServerSocketChannel.class)
                     .childHandler(new ChannelInitializer<SocketChannel>() {
                         @Override
                         protected void initChannel(SocketChannel ch) throws Exception {
                             ch.pipeline()
                               .addLast(new ObjectDecoder(ClassResolvers
                               .weakCachingConcurrentResolver(null)))
                               .addLast(new ObjectEncoder())
                               .addLast(new RpcServerHandler());
                         }
                     });

            ChannelFuture future = bootstrap.bind(port).sync();
            System.out.println("Server started on port " + port);
            future.channel().closeFuture().sync();
        } finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        new RpcServer().start(8080);
    }
}

客户端代码：

public class RpcClient {
    private final String host;
    private final int port;

    public RpcClient(String host, int port) {
        this.host = host;
        this.port = port;
    }

    public Object sendRequest(RpcRequest request) throws Exception {
        EventLoopGroup group = new NioEventLoopGroup();

        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(group)
                     .channel(NioSocketChannel.class)
                     .handler(new ChannelInitializer<SocketChannel>() {
                         @Override
                         protected void initChannel(SocketChannel ch) throws Exception {
                             ch.pipeline()
                               .addLast(new ObjectDecoder(ClassResolvers
                               .weakCachingConcurrentResolver(null)))
                               .addLast(new ObjectEncoder())
                               .addLast(new RpcClientHandler());
                         }
                     });

            ChannelFuture future = bootstrap.connect(host, port).sync();
            future.channel().writeAndFlush(request).sync();
            future.channel().closeFuture().sync();
            return RpcClientHandler.getResponse();
        } finally {
            group.shutdownGracefully();
        }
    }

    public static void main(String[] args) throws Exception {
        RpcClient client = new RpcClient("localhost", 8080);

        RpcRequest request = new RpcRequest();
        request.setClassName("com.example.MyService");
        request.setMethodName("sayHello");
        request.setParameterTypes(new Class[]{String.class});
        request.setArguments(new Object[]{"World"});

        Object response = client.sendRequest(request);
        System.out.println(response);
    }
}

其中，RpcRequest是一个自定义的类，用于封装RPC请求的信息。RpcServerHandler和RpcClientHandler则分别是服务端和客户端的处理器，用于处理具体的请求和响应。