7.3 netty3基本使用

由於dubbo默認使用的是netty3進行通信的，這里簡單的列出一個netty3通信的例子。

一 server端

1 Server

package com.hulk.netty.server;

import org.jboss.netty.bootstrap.ServerBootstrap;
import org.jboss.netty.channel.*;
import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
import org.jboss.netty.handler.codec.string.StringDecoder;
import org.jboss.netty.handler.codec.string.StringEncoder;

import java.net.InetSocketAddress;
import java.util.concurrent.Executors;

public class Server {
    public void start(){
        ChannelFactory factory = new NioServerSocketChannelFactory(
                Executors.newCachedThreadPool(),//boss線程池
                Executors.newCachedThreadPool(),//worker線程池
                8//worker線程數
        );
        ServerBootstrap bootstrap = new ServerBootstrap(factory);
        /**
         * 對於每一個連接channel, server都會調用PipelineFactory為該連接創建一個ChannelPipline
         */
        bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
            public ChannelPipeline getPipeline() throws Exception {
                ChannelPipeline pipeline = Channels.pipeline();
                pipeline.addLast("decoder", new StringDecoder());
                pipeline.addLast("encoder", new StringEncoder());
                pipeline.addLast("handler", new ServerLogicHandler());
                return pipeline;
            }
        });

        Channel channel = bootstrap.bind(new InetSocketAddress("127.0.0.1", 8080));
        System.out.println("server start success!");
    }

    public static void main(String[] args) throws InterruptedException {
        Server server = new Server();
        server.start();
        Thread.sleep(Integer.MAX_VALUE);
    }
}

步驟：

• 首先創建了NioServerSocketChannelFactory：創建boss線程池，創建worker線程池以及worker線程數。（boss線程數默認為1個）
• 創建ServerBootstrap server端啟動輔助類
• 為ServerBootstrap設置ChannelPipelineFactory工廠，並為ChannelPipelineFactory將來創建出的ChannelPipeline設置編碼器／解碼器／事件處理器
• 使用ServerBootstrap綁定監聽地址和端口

2 事件處理器ServerLogicHandler

package com.hulk.netty.server;

import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelHandler;

public class ServerLogicHandler extends SimpleChannelHandler {
    @Override
    public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
        System.out.println("連接成功, channel: " + e.getChannel().toString());
    }

    @Override
    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
        String msg = (String) e.getMessage();
        System.out.println("接收到了client的消息, msg: " + msg);

        Channel channel = e.getChannel();
        String str = "hi, client";

        channel.write(str);//寫消息發給client端
        System.out.println("服務端發送數據: " + str + "完成");
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {
        e.getCause().printStackTrace();
        e.getChannel().close();
    }
}

說明：

• 監聽與客戶端連接成功事件
• 監聽接收到來自客戶端的消息，之后寫回給客戶端消息
• 捕捉異常事件

二 client端

1 Client

package com.hulk.netty.client;

import org.jboss.netty.bootstrap.ClientBootstrap;
import org.jboss.netty.channel.ChannelFactory;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;
import org.jboss.netty.handler.codec.string.StringDecoder;
import org.jboss.netty.handler.codec.string.StringEncoder;

import java.net.InetSocketAddress;
import java.util.concurrent.Executors;

public class Client {
    public static void main(String[] args) {
        ChannelFactory factory = new NioClientSocketChannelFactory(
                Executors.newCachedThreadPool(),
                Executors.newCachedThreadPool(),
                8
        );
        ClientBootstrap bootstrap = new ClientBootstrap(factory);
        bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
            public ChannelPipeline getPipeline() throws Exception {
                ChannelPipeline pipeline = Channels.pipeline();
                pipeline.addLast("decoder", new StringDecoder());
                pipeline.addLast("encoder", new StringEncoder());
                pipeline.addLast("handler", new ClientLogicHandler());
                return pipeline;
            }
        });

        bootstrap.connect(new InetSocketAddress("127.0.0.1", 8080));
        System.out.println("client start success!");
    }
}

步驟：（與Server幾乎相同）

• 首先創建了NioClientSocketChannelFactory：創建boss線程池，創建worker線程池以及worker線程數。（boss線程數默認為1個）
• 創建ClientBootstrap client端啟動輔助類
• 為ClientBootstrap設置ChannelPipelineFactory工廠，並為ChannelPipelineFactory將來創建出的ChannelPipeline設置編碼器／解碼器／事件處理器
• 使用ClientBootstrap連接Server端監聽的地址和端口

2 ClientLogicHandler

package com.hulk.netty.client;

import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelHandler;
import org.jboss.netty.channel.WriteCompletionEvent;

public class ClientLogicHandler extends SimpleChannelHandler {
    @Override
    public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
        System.out.println("客戶端連接成功!");
        String str = "hi server!";
        e.getChannel().write(str);//異步
    }

    @Override
    public void writeComplete(ChannelHandlerContext ctx, WriteCompletionEvent e) throws Exception {
        System.out.println("客戶端寫消息完成");
    }

    @Override
    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {
        String msg = (String) e.getMessage();
        System.out.println("客戶端接收到消息, msg: " + msg);
    }

    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {
        e.getCause().printStackTrace();
        e.getChannel().close();
    }
}

說明：

• 監聽與服務端連接成功事件，連接成功后，寫消息給服務端
• 監聽向服務端寫消息完成的事件
• 監聽接收到來自服務端的消息
• 捕捉異常事件

 

這就是一個簡單的netty3通信的例子，關於netty，后續會讀源碼。