Netty入门示例

1、Netty软件包下载：http://netty.io/downloads.html，本示例基于netty-5.0.0.Alpha2.tar.bz2

2、搭建Netty应用工程

     使用eclipse创建一个java工程，新建lib文件夹并将netty-all-5.0.0.Alpha2.jar复制到该文件夹下，然后将jar引入工程。

3、Netty服务端开发

    TimeServer.java

package com.neety;

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 TimeServer {

	public void bind(int port)throws Exception{
		
		//配置服务端Nio线程组
		EventLoopGroup bossGroup = new NioEventLoopGroup();
		EventLoopGroup workerGroup = new NioEventLoopGroup();
		try{
			ServerBootstrap b = new ServerBootstrap();
			b.group(bossGroup, workerGroup)
				.channel(NioServerSocketChannel.class)
				.option(ChannelOption.SO_BACKLOG, 1024)
				//.childHandler(new TimeServerHandler());
				.childHandler(new ChildChannelHandler());
			//绑定端口，同步等待成功
			ChannelFuture f = b.bind(port).sync();
			//等待服务端监听端口关闭
			f.channel().closeFuture().sync();
			
		}finally{
			//退出时释放资源
			bossGroup.shutdownGracefully();
			workerGroup.shutdownGracefully();
		}		
	}
	

	private class ChildChannelHandler extends ChannelInitializer<SocketChannel>{
		@Override
		protected void initChannel(SocketChannel channel) throws Exception {
			channel.pipeline().addLast(new TimeServerHandler());
		}		
	}
		
	public static void main(String[] args) throws Exception{
		int port = 8083;
		if(args!=null && args.length > 0){
			port = Integer.valueOf(args[0]);
		}
		new TimeServer().bind(port);		
	}
}

 

    TimeServerHandler.java

package com.neety;

import java.util.Date;

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

public class TimeServerHandler extends ChannelHandlerAdapter {

	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg)
			throws Exception {
		//super.channelRead(ctx, msg);
		ByteBuf buf = (ByteBuf) msg;
		byte [] req = new byte[buf.readableBytes()];
		buf.readBytes(req);
		String body = new String(req,"UTF-8");
		System.out.println("The time server receive order:"+body);		
		String currentTime = "query time order".equalsIgnoreCase(body)?new Date(
				System.currentTimeMillis()).toString():"bad order";
		ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
		ctx.write(resp);		
	}
	
	@Override
	public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
		//super.channelReadComplete(ctx);
		ctx.flush();
	}
	
	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
			throws Exception {
		//super.exceptionCaught(ctx, cause);
		ctx.close();
	}
	
}

 

 

4、Netty客户端开发

    TimeClient.java

package com.neety;

import io.netty.bootstrap.Bootstrap;
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.NioSocketChannel;

public class TimeClient {
	
	public void connect(int port,String host)throws Exception{
		
		//配置客户端NIO线程组
		EventLoopGroup group = new NioEventLoopGroup();
		
		try{
			Bootstrap b = new Bootstrap();
			b.group(group).channel(NioSocketChannel.class)
				.option(ChannelOption.TCP_NODELAY, true)
				.handler(new ChannelInitializer<SocketChannel>() {
					protected void initChannel(SocketChannel ch) throws Exception {
						ch.pipeline().addLast(new TimeClientHandler());					
					};
				});
			
			//发起异步连接操作
			ChannelFuture f = b.connect(host,port).sync();
			//等待客户端链路关闭
			f.channel().closeFuture().sync();
		}finally{
			//退出，释放资源
			group.shutdownGracefully();
		}
		
	}
	
	public static void main(String[] args)throws Exception {
		int port = 8083;
		if(args!=null && args.length > 0){
			port = Integer.valueOf(args[0]);
		}
		new TimeClient().connect(port, "127.0.0.1");		
	}
}

 

    TimeClientHandler.java

package com.neety;

import java.util.logging.Logger;

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

/**
 * 
 * @author Administrator
 *
 */
public class TimeClientHandler extends ChannelHandlerAdapter {

	private static final Logger logger = Logger.getLogger(TimeClientHandler.class.getName());
	
	private final ByteBuf firstMessage;
	public TimeClientHandler() {
		byte [] req = "query time order".getBytes();
		firstMessage = Unpooled.buffer(req.length);
		firstMessage.writeBytes(req);		
	}
	
	@Override
	public void channelActive(ChannelHandlerContext ctx) throws Exception {
		//super.channelActive(ctx);
		ctx.writeAndFlush(firstMessage);
	}
	
	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg)
			throws Exception {
		//super.channelRead(ctx, msg);
		ByteBuf buf = (ByteBuf)msg;
		byte [] req = new byte[buf.readableBytes()];
		buf.readBytes(req);
		String body = new String(req, "UTF-8");
		System.out.println("now is :"+body);
	}
	
	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)
			throws Exception {
		//super.exceptionCaught(ctx, cause);
		logger.warning("unexpected exception from downstream:"+ cause.getMessage());
		ctx.close();
	}
	
}

 

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