Netty4具体解释二：开发第一个Netty应用程序

package NettyDemo.echo.server;

import io.netty.bootstrap.ServerBootstrap;
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.NioServerSocketChannel;
import java.net.InetSocketAddress;
import NettyDemo.echo.handler.EchoServerHandler;
public class EchoServer {
	private static final int port = 8080;
	public void start() throws InterruptedException {
		ServerBootstrap b = new ServerBootstrap();// 引导辅助程序
		EventLoopGroup group = new NioEventLoopGroup();// 通过nio方式来接收连接和处理连接
		try {
			b.group(group);
			b.channel(NioServerSocketChannel.class);// 设置nio类型的channel
			b.localAddress(new InetSocketAddress(port));// 设置监听端口
			b.childHandler(new ChannelInitializer<SocketChannel>() {//有连接到达时会创建一个channel
						protected void initChannel(SocketChannel ch) throws Exception {
							// pipeline管理channel中的Handler，在channel队列中加入一个handler来处理业务
							ch.pipeline().addLast("myHandler", new EchoServerHandler());
						}
					});
			ChannelFuture f = b.bind().sync();// 配置完毕，開始绑定server，通过调用sync同步方法堵塞直到绑定成功
			System.out.println(EchoServer.class.getName() + " started and listen on " + f.channel().localAddress());
			f.channel().closeFuture().sync();// 应用程序会一直等待，直到channel关闭
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			group.shutdownGracefully().sync();//关闭EventLoopGroup，释放掉全部资源包含创建的线程
		}
	}
	public static void main(String[] args) {
		try {
			new EchoServer().start();
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
	}
}

1. 连接到Server
2. 向Server写数据
3. 等待Server返回数据
4. 关闭连接

package NettyDemo.echo.client;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
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;

import java.net.InetSocketAddress;

import NettyDemo.echo.handler.EchoClientHandler;

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

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

	public void start() throws Exception {
		EventLoopGroup group = new NioEventLoopGroup();
		try {
			Bootstrap b = new Bootstrap();
			b.group(group);
			b.channel(NioSocketChannel.class);
			b.remoteAddress(new InetSocketAddress(host, port));
			b.handler(new ChannelInitializer<SocketChannel>() {

				public void initChannel(SocketChannel ch) throws Exception {
					ch.pipeline().addLast(new EchoClientHandler());
				}
			});
			ChannelFuture f = b.connect().sync();
			f.addListener(new ChannelFutureListener() {
				
				public void operationComplete(ChannelFuture future) throws Exception {
					if(future.isSuccess()){
						System.out.println("client connected");
					}else{
						System.out.println("server attemp failed");
						future.cause().printStackTrace();
					}
					
				}
			});
			f.channel().closeFuture().sync();
		} finally {
			group.shutdownGracefully().sync();
		}
	}

	public static void main(String[] args) throws Exception {
	
		new EchoClient("127.0.0.1", 3331).start();
	}
}