The first NETTY example

package netty1;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;

public class Server {

	public static void main(String[] args) throws Exception {
		//1 The first thread group is used to receive client connections
		EventLoopGroup bossGroup = new NioEventLoopGroup();
		//2 The second thread group is used for actual business processing operations
		EventLoopGroup workerGroup = new NioEventLoopGroup();
		
		//3 Create an auxiliary class Bootstrap, which is a series of configurations for our Server
		ServerBootstrap b = new ServerBootstrap();
		//Add two worker thread groups to it
		b.group(bossGroup, workerGroup)
		//I want to specify a channel of this type using NioServerSocketChannel
		 .channel(NioServerSocketChannel.class)
		//Be sure to use childHandler to bind specific event handlers
		 .childHandler(new ChannelInitializer<SocketChannel>() {
			@Override
			protected void initChannel(SocketChannel sc) throws Exception {
				sc.pipeline().addLast(new ServerHandler());
			}
		});

		//Bind the specified port to listen
		ChannelFuture f = b.bind(8765).sync();
		
		f.channel().closeFuture().sync();//Indicates that it has been blocked until it is closed. Equivalent to Thread.sleep(1000000);
		
		bossGroup.shutdownGracefully();
		workerGroup.shutdownGracefully();
		 
		
		
	}
	
}

 

package netty1;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.util.ReferenceCountUtil;

public class ServerHandler  extends ChannelHandlerAdapter {

	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
	
			//do something msg
			ByteBuf buf = (ByteBuf)msg;
			byte[] data = new byte[buf.readableBytes()];
			buf.readBytes(data);
			String request = new String(data, "utf-8");
			System.out.println("Server: " + request);
			// write to client
			String response = "I am the feedback message";
			ctx.writeAndFlush(Unpooled.copiedBuffer("888".getBytes()));
			//.addListener(ChannelFutureListener.CLOSE);
			

	}

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

}

 

package netty1;

import io.netty.bootstrap.Bootstrap;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;

public class Client {

	public static void main(String[] args) throws Exception {
		
		EventLoopGroup workgroup = new NioEventLoopGroup();
		Bootstrap b = new Bootstrap();
		b.group(workgroup)
		.channel(NioSocketChannel.class)//TCP client uses NioSocketChannel channel
		.handler(new ChannelInitializer<SocketChannel>() {//handler is different from the server
			@Override
			protected void initChannel(SocketChannel sc) throws Exception {
				sc.pipeline().addLast(new ClientHandler());
			}
		});
		
		ChannelFuture cf1 = b.connect("127.0.0.1", 8765).sync();
		
		//buf
		cf1.channel().writeAndFlush(Unpooled.copiedBuffer("777".getBytes()));
		
		cf1.channel().closeFuture().sync();//Indicates that it has been blocked until it is closed.
		workgroup.shutdownGracefully();
		
	}
}

 

package netty1;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;
import io.netty.util.ReferenceCountUtil;

public class ClientHandler extends ChannelHandlerAdapter {

	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
		try {
			//do something msg
			ByteBuf buf = (ByteBuf)msg;
			byte[] data = new byte[buf.readableBytes()];
			buf.readBytes(data);
			String request = new String(data, "utf-8");
			System.out.println("Client: " + request);
			
			
		} finally {
			ReferenceCountUtil.release(msg);
		}
	}

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