Netty模拟dubbo RPC调用看着视频敲的

1.服务接口和实现类

package dubborpc.publicinterface;

//一个接口，服务提供方和 服务消费方都需要
public interface DemoService {

    String hello(String str);
}

package dubborpc.provider;


import dubborpc.publicinterface.DemoService;

public class DemoServiceImpl implements DemoService {

    private static int count = 0;
    //当有消费方调用该方法时， 就返回一个结果
    @Override
    public String hello(String mes) {
        System.out.println("收到客户端消息= " + mes);
        //根据mes 返回不同的结果
        if(mes != null) {
            return "服务器收到消息  [" + mes + "] 第" + (++count) + " 次";
        } else {
            return "服务器收到消息";
        }
    }
}

2.Netty服务器

package dubborpc.netty;


import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

public class NettyServer {


    public static void startServer0(String hostName, int port) {
        startServer(hostName,port);
    }

    //编写一个方法，完成对NettyServer的初始化和启动

    private static void startServer(String hostname, int port) {

        EventLoopGroup bossGroup = new NioEventLoopGroup(1);
        EventLoopGroup workerGroup = new NioEventLoopGroup();

        try {

            ServerBootstrap serverBootstrap = new ServerBootstrap();

            serverBootstrap.group(bossGroup,workerGroup)
                    .channel(NioServerSocketChannel.class)
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                                      @Override
                                      protected void initChannel(SocketChannel ch) throws Exception {
                                          ChannelPipeline pipeline = ch.pipeline();
                                          pipeline.addLast(new StringDecoder());
                                          pipeline.addLast(new StringEncoder());
                                          pipeline.addLast(new NettyServerHandler()); //业务处理器

                                      }
                                  }

                    );

            ChannelFuture channelFuture = serverBootstrap.bind(hostname, port).sync();
            System.out.println("服务提供方开始提供服务~~");
            channelFuture.channel().closeFuture().sync();

        }catch (Exception e) {
            e.printStackTrace();
        }
        finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
        }

    }
}

package dubborpc.netty;



import dubborpc.customer.ClientBootstrap;
import dubborpc.provider.DemoServiceImpl;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

//服务器handler
public class NettyServerHandler extends ChannelInboundHandlerAdapter {

    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        //获取客户端发送的消息，并调用服务
        System.out.println("msg=" + msg);
        //客户端在调用服务器的api 时，我们需要定义一个协议
        //比如我们要求 每次发消息是都必须以某个字符串开头 "$"
        if(msg.toString().startsWith(ClientBootstrap.providerName)) {

            String result = new DemoServiceImpl().hello(msg.toString().substring(msg.toString().lastIndexOf("$") + 1));
            ctx.writeAndFlush(result);
        }
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
    }
}

3.客户端

package dubborpc.netty;


import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

import java.lang.reflect.Proxy;
import java.util.concurrent.Executor;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

public class NettyClient {

    //创建线程池
    private static ExecutorService executor = Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());

    private static NettyClientHandler client;
    private int count = 0;

    //编写方法使用代理模式，获取一个代理对象

    public Object getBean(final Class<?> serivceClass, final String providerName) {

        return Proxy.newProxyInstance(Thread.currentThread().getContextClassLoader(),
                new Class<?>[]{serivceClass}, (proxy, method, args) -> {

                    System.out.println("(proxy, method, args) 进入...." + (++count) + " 次");
                    //{}  部分的代码，客户端每调用一次 hello, 就会进入到该代码
                    if (client == null) {
                        initClient();
                    }

                    //设置要发给服务器端的信息
                    //providerName 协议头 args[0] 就是客户端调用api hello(???), 参数
                    client.setPara(providerName + args[0]);

                    //
                    return executor.submit(client).get();

                });
    }

    //初始化客户端
    private static void initClient() {
        client = new NettyClientHandler();
        //创建EventLoopGroup
        NioEventLoopGroup group = new NioEventLoopGroup();
        Bootstrap bootstrap = new Bootstrap();
        bootstrap.group(group)
                .channel(NioSocketChannel.class)
                .option(ChannelOption.TCP_NODELAY, true)
                .handler(
                        new ChannelInitializer<SocketChannel>() {
                            @Override
                            protected void initChannel(SocketChannel ch) throws Exception {
                                ChannelPipeline pipeline = ch.pipeline();
                                pipeline.addLast(new StringDecoder());
                                pipeline.addLast(new StringEncoder());
                                pipeline.addLast(client);
                            }
                        }
                );

        try {
            bootstrap.connect("127.0.0.1", 7000).sync();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

package dubborpc.netty;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;

import java.util.concurrent.Callable;

public class NettyClientHandler extends ChannelInboundHandlerAdapter implements Callable {

    private ChannelHandlerContext context;//上下文
    private String result; //返回的结果
    private String para; //客户端调用方法时，传入的参数


    //与服务器的连接创建后，就会被调用,
    // 第一个被调用(1)
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println(" channelActive 被调用  ");
        context = ctx; //因为我们在其它方法会使用到 ctx
    }

    //收到服务器的数据后，调用方法 (4)
    //
    @Override
    public synchronized void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
        System.out.println(" channelRead 被调用  ");
        result = msg.toString();
        notify(); //唤醒等待的线程
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close();
    }

    //被代理对象调用, 发送数据给服务器，-> wait -> 等待被唤醒(channelRead) -> 返回结果 (3)-》5
    @Override
    public synchronized Object call() throws Exception {
        System.out.println(" call1 被调用  ");
        context.writeAndFlush(para);
        //进行wait
        wait(); //等待channelRead 方法获取到服务器的结果后，唤醒
        System.out.println(" call2 被调用  ");
        return  result; //服务方返回的结果

    }
    //(2)
    void setPara(String para) {
        System.out.println(" setPara  ");
        this.para = para;
    }
}

4.服务启动线程和客户启动线程

package dubborpc.provider;


import dubborpc.netty.NettyServer;

//ServerBootstrap 会启动一个服务提供者，就是 NettyServer
public class ServerBootstrap {
    public static void main(String[] args) {

        NettyServer.startServer0("127.0.0.1", 7000);
    }
}

package dubborpc.customer;


import dubborpc.netty.NettyClient;
import dubborpc.publicinterface.DemoService;

public class ClientBootstrap {


    //这里定义协议头
    public static final String providerName = "$";

    public static void main(String[] args) throws  Exception{

        //创建一个消费者
        NettyClient customer = new NettyClient();

        //创建代理对象
        DemoService service = (DemoService) customer.getBean(DemoService.class, providerName);

        for (;; ) {
            Thread.sleep(2 * 1000);
            //通过代理对象调用服务提供者的方法(服务)
            String res = service.hello(" 你好 dubbo~");
            System.out.println("调用的结果 res= " + res);
        }
    }
}