使用netty的NIO来实现一个简单的TimeServer

只想以此来加深java的NIO这方面的知识点~~~

参考书籍《netty权威指南》(第二版)

这本书，第一二三章，前面讲java的bio,nio,nio2，

讲得蛮好的。

package com.phei.netty;

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 {
		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 ChildChannelHandler());
			ChannelFuture f = b.bind(port).sync();
			f.channel().closeFuture().sync();
		} finally {
			bossGroup.shutdownGracefully();
			workerGroup.shutdownGracefully();
		}
	}
	
	private class ChildChannelHandler extends ChannelInitializer<SocketChannel> {
		protected void initChannel(SocketChannel arg0) throws Exception {
			arg0.pipeline().addLast(new TimeServerHandler());
		}
	}
	
	public static void main(String[] args) throws Exception {
		int port = 8080;
		if (args != null && args.length > 0) {
			try {
				port = Integer.valueOf(args[0]);
			} catch (NumberFormatException e) {
				e.printStackTrace();
			}
		}
		System.out.println("The time server is start in port: " + port);
		new TimeServer().bind(port);
		System.out.println("The time server is start in port: " + port);
	}

}

package com.phei.netty;

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 {
	
	public void channelRead(ChannelHandlerContext ctx, Object msg) 
		throws Exception {
		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 java.util.Date(System.currentTimeMillis()).toString() : "BAD ORDER";
				ByteBuf resp = Unpooled.copiedBuffer(currentTime.getBytes());
				ctx.write(resp);
	}
	
	public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
		ctx.flush();
	}
	
	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
		ctx.close();
	}

}

package com.phei.netty;

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 {
		EventLoopGroup group = new NioEventLoopGroup();
		try {
			Bootstrap b = new Bootstrap();
			b.group(group).channel(NioSocketChannel.class)
			.option(ChannelOption.TCP_NODELAY, true)
			.handler(new ChannelInitializer<SocketChannel>() {
				@Override
				public void initChannel(SocketChannel ch) throws Exception {
					ch.pipeline().addLast(new TimeClientHandler());
				}
			});
			ChannelFuture f = b.connect(host, port).sync();
			f.channel().closeFuture().sync();
			
		} finally {
			group.shutdownGracefully();
		}
	}

	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		int port = 8080;
		if (args != null && args.length > 0) {
			try {
				port = Integer.valueOf(args[0]);
			} catch (NumberFormatException e) {
				e.printStackTrace();
			}
		}
		new TimeClient().connect(port, "localhost");

	}

}

package com.phei.netty;

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;

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);
	}
	
	public void channelActive(ChannelHandlerContext ctx) {
		ctx.writeAndFlush(firstMessage);
	}
	
	public void channelRead(ChannelHandlerContext ctd, Object msg) throws Exception {
		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);
	}
	
	public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
		logger.warning("Unexpected exception from downstream: " + cause.getMessage());
		ctx.close();
	}

}