通信框架netty5.0教程一：使用netty开发简单样例

Netty是什么？

本质：JBoss做的一个Jar包

目的：快速开发高性能、高可靠性的网络服务器和客户端程序

优点：提供异步的、事件驱动的网络应用程序框架和工具

通俗的说：一个好使的处理Socket的东东

Netty的特性

设计
统一的API，适用于不同的协议（阻塞和非阻塞）
基于灵活、可扩展的事件驱动模型
高度可定制的线程模型
可靠的无连接数据Socket支持（UDP）

性能
更好的吞吐量，低延迟
更省资源
尽量减少不必要的内存拷贝

安全
完整的SSL/TLS和STARTTLS的支持
能在Applet与Android的限制环境运行良好

健壮性
不再因过快、过慢或超负载连接导致OutOfMemoryError
不再有在高速网络环境下NIO读写频率不一致的问题

易用
完善的JavaDoc，用户指南和样例
简洁简单

下面提供一个简单的例子

第一步：下载netty5.0

移步官网下载 http://netty.io/downloads.html或者
使用maven，在pom.xml中添加如下代码

<dependency><groupId>io.netty</groupId><artifactId>netty-all</artifactId><version>5.0.0.Alpha2</version></dependency>

第二步： 编写Server端代码

NettyServerBootstrap代码

import java.util.concurrent.TimeUnit;

import org.apache.log4j.Logger;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
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 io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.timeout.IdleStateHandler;

public class NettyServerBootstrap {

	private static Logger logger = Logger.getLogger(NettyServerBootstrap.class);

	private int port;

	public NettyServerBootstrap(int port) {
		this.port = port;
		bind();
	}

	private void bind() {

		EventLoopGroup boss = new NioEventLoopGroup();
		EventLoopGroup worker = new NioEventLoopGroup();

		try {

			ServerBootstrap bootstrap = new ServerBootstrap();

			bootstrap.group(boss, worker);
			bootstrap.channel(NioServerSocketChannel.class);
			bootstrap.option(ChannelOption.SO_BACKLOG, 1024); //连接数
			bootstrap.option(ChannelOption.TCP_NODELAY, true);  //不延迟，消息立即发送
			bootstrap.childOption(ChannelOption.SO_KEEPALIVE, true); //长连接
			bootstrap.childHandler(new ChannelInitializer<SocketChannel>() {
				@Override
				protected void initChannel(SocketChannel socketChannel)
						throws Exception {
					ChannelPipeline p = socketChannel.pipeline();
					p.addLast(new NettyServerHandler());
				}
			});
			ChannelFuture f = bootstrap.bind(port).sync();
			if (f.isSuccess()) {
				logger.debug("启动Netty服务成功，端口号：" + this.port);
			}
			// 关闭连接
			f.channel().closeFuture().sync();

		} catch (Exception e) {
			logger.error("启动Netty服务异常，异常信息：" + e.getMessage());
			e.printStackTrace();
		} finally {
			boss.shutdownGracefully();
			worker.shutdownGracefully();
		}
	}

public static void main(String[] args) throws InterruptedException {
		
		NettyServerBootstrap server= new NettyServerBootstrap(9999);

	}

}

 

NettyServerHandler代码

import java.io.UnsupportedEncodingException;

import com.datong.base.module.netty.common.Constant;

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

public class NettyServerHandler extends ChannelHandlerAdapter {

	@Override
	public void channelRead(ChannelHandlerContext ctx, Object msg) {
		
		ByteBuf buf = (ByteBuf) msg;
		
		String recieved = getMessage(buf);
		System.out.println("服务器接收到消息：" + recieved);
		try {
			ctx.writeAndFlush(getSendByteBuf("APPLE"));
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		}
	}

	/*
	 * 从ByteBuf中获取信息 使用UTF-8编码返回
	 */
	private String getMessage(ByteBuf buf) {

		byte[] con = new byte[buf.readableBytes()];
		buf.readBytes(con);
		try {
			return new String(con, Constant.UTF8);
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
			return null;
		}
	}
	
	private ByteBuf getSendByteBuf(String message)
			throws UnsupportedEncodingException {

		byte[] req = message.getBytes("UTF-8");
		ByteBuf pingMessage = Unpooled.buffer();
		pingMessage.writeBytes(req);

		return pingMessage;
	}
}

第三步：编写Client代码

NettyClient代码

import java.util.concurrent.TimeUnit;

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;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.timeout.IdleStateHandler;

public class NettyClient {

	/*
	 * 服务器端口号
	 */
	private int port;

	/*
	 * 服务器IP
	 */
	private String host;

	public NettyClientBootstrap(int port, String host)
			throws InterruptedException {
		this.port = port;
		this.host = host;
		start();
	}

	private void start() throws InterruptedException {
		
		EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
		
		try {
			
			Bootstrap bootstrap = new Bootstrap();
			bootstrap.channel(NioSocketChannel.class);
			bootstrap.option(ChannelOption.SO_KEEPALIVE, true);
			bootstrap.group(eventLoopGroup);
			bootstrap.remoteAddress(host, port);
			bootstrap.handler(new ChannelInitializer<SocketChannel>() {
				@Override
				protected void initChannel(SocketChannel socketChannel)
						throws Exception {					
					socketChannel.pipeline().addLast(new NettyClientHandler());
				}
			});
			ChannelFuture future = bootstrap.connect(host, port).sync();
			if (future.isSuccess()) {
				socketChannel = (SocketChannel) future.channel();
				System.out.println("----------------connect server success----------------");
			}
			future.channel().closeFuture().sync();
		} finally {
			eventLoopGroup.shutdownGracefully();
		}
	}

	public static void main(String[] args) throws InterruptedException {
		
		NettyClient client = new NettyClient(9999,
				"localhost");

	}
}

NettyClientHandler代码

import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.concurrent.TimeUnit;

import com.netty.common.NettyStartRunable;
import com.netty.common.ProxyPool;
import com.netty.util.JsonUtil;

import net.sf.json.JSONObject;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerAdapter;
import io.netty.channel.ChannelHandlerContext;

public class NettyClientHandler extends ChannelHandlerAdapter  {

    private  ByteBuf firstMessage;
    
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
    	
    	byte[] data = "服务器，给我一个APPLE".getBytes();
    	firstMessage=Unpooled.buffer();
        firstMessage.writeBytes(data);
        ctx.writeAndFlush(firstMessage);
    }
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg)
            throws Exception {
        ByteBuf buf = (ByteBuf) msg;
	String rev = getMessage(bug);

	System.out.println("客户端收到服务器数据:" + rev);
    }
    private String getMessage(ByteBuf buf) {

		byte[] con = new byte[buf.readableBytes()];
		buf.readBytes(con);
		try {
			return new String(con, Constant.UTF8);
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
			return null;
		}
	}
}

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