netty简单的服务端和客户端创建

1、 Netty前言：高性能的三大主题：1) 传输：用什么样的通道将数据发送给对方，BIO、NIO或者AIO，IO模型在很大程度上决定了框架的性能。2) 协议：采用什么样的通信协议，HTTP或者内部私有协议。协议的选择不同，性能模型也不同。相比于公有协议，内部私有协议的性能通常可以被设计的更优。3) 线程：数据报如何读取？读取之后的编解码在哪个线程进行，编解码后的消息如何派发，Reactor线程模型的不同，对性能的影响也非常大。Netty 高性能的表现：1. 异步非阻塞通信2. 零拷贝1) Netty的接收和发送ByteBuffer采用DIRECT BUFFERS，使用堆外直接内存进行Socket

2、读写，不需要进行字节缓冲区的二次拷贝2) Netty提供了组合Buffer对象，可以聚合多个ByteBuffer对象，用户可以像操作一个Buffer那样方便的对组合Buffer进行操作，避免系统统通过内存拷贝的方式将几个小Buffer合并成一个大的Buffer。3) Netty的文件传输采用了transferTo方法，它可以直接将文件缓冲区的数据发送到目标Channel，避免了传统通过循环write方式导致的内存拷贝问题。3. 内存池4. 高效的Reactor线程模型5. 无锁化的串行设计理念6. 高效的并发编程7. 高性能的序列化框架8. 灵活的TCP参数配置能力Netty 服务端创建（详细

3、解析）：1. 创建TimeService：代码如下：package ty.demo;import ty.bootstrap.ServerBootstrap;import ty.channel.ChannelFuture;import ty.channel.ChannelInitializer;import ty.channel.ChannelOption;import ty.channel.ChannelPipeline;import ty.channel.EventLoopGroup;import ty.channel.nio.NioEventLoopGroup;import ty.chan

4、nel.socket.SocketChannel;import ty.channel.socket.nio.NioServerSocketChannel;import ty.handler.codec.DelimiterBasedFrameDecoder;import ty.handler.codec.Delimiters;import ty.handler.codec.string.StringDecoder;import ty.handler.codec.string.StringEncoder;/* * Time Netty服务端 * * author zhouxm * */public

5、 class TimeService public void bind(int port) throws Exception / 配置NIO服务端线程组EventLoopGroup bossGroup = new NioEventLoopGroup();/ 用于服务端接收客户端的链接EventLoopGroup workGroup = new NioEventLoopGroup();/ 用于SocketChannel网络读写try / 创建NIO服务端辅助启动类ServerBootstrap b = new ServerBootstrap();b.group(bossGroup, workGr

6、oup).channel(NioServerSocketChannel.class).option(ChannelOption.SO_BACKLOG, 1024).childHandler(new ChildChannelHander();/ 绑定监听端口，同步等待成功ChannelFuture f = b.bind(port).sync();/ 等待监听端口关闭f.channel().closeFuture().sync();/ b.bind(port).sync().channel().closeFuture().sync();/也可以这样将上面两步骤合并，使代码更简洁 finally /

7、 退出，释放线程池资源bossGroup.shutdownGracefully();workGroup.shutdownGracefully();/ 用户处理网络IO事件,类似于Reactor模式中的handle类 例：消息编解码 日志打印private class ChildChannelHander extends ChannelInitializer<SocketChannel> Overrideprotected void initChannel(SocketChannel arg0) throws Exception / TODO Auto-generated metho

8、d stubChannelPipeline pipeline = arg0.pipeline();/ 以("n")为结尾分割的 解码器pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192,Delimiters.lineDelimiter();/ 字符串解码 和 编码pipeline.addLast("decoder", new StringDecoder();pipeline.addLast("encoder", new StringEncod

9、er();/ 自己的逻辑Handlerpipeline.addLast("handler", new TimeServerHander();public static void main(String args)int port = 8080;try new TimeService().bind(port); catch (Exception e) / TODO Auto-generated catch blocke.printStackTrace();2. TimeServerHander：代码如下：package ty.demo;import ty.buffer.Byt

10、eBuf;import ty.buffer.Unpooled;import ty.channel.ChannelHandlerAdapter;import ty.channel.ChannelHandlerContext;/* * 逻辑handle类 * * author zhouxm * */public class TimeServerHander extends ChannelHandlerAdapter /* * (non-Javadoc) * * see * ty.channel.ChannelHandlerAdapter#channelActive(ty.channel * .Ch

11、annelHandlerContext) */Overridepublic void channelActive(ChannelHandlerContext ctx) throws Exception / TODO Auto-generated method stubsuper.channelActive(ctx);/* * (non-Javadoc) * * see ty.channel.ChannelHandlerAdapter#channelRead(ty.channel. * ChannelHandlerContext, java.lang.Object) */Overridepubl

12、ic void channelRead(ChannelHandlerContext ctx, Object msg)throws Exception / TODO Auto-generated method stubByteBuf buf = (ByteBuf) msg;/ 将msg转换成Netty ByteBuf 类似于jdk中的ByteBufferbyte req = new bytebuf.readableBytes();/ 根据字节数创建byte数组buf.readBytes(req);/ 将缓冲区中的字节数组复制到 byte数组中String body = new String(re

13、q, "utf-8");/ 创建构造函数接收消息System.out.print("client send message :" + body);/ 打印String resString = "response msg to client "ByteBuf b = Unpooled.copiedBuffer(resString.getBytes();ctx.write(b);/ 发送消息给客户端/* * (non-Javadoc) * * see * ty.channel.ChannelHandlerAdapter#channelRe

14、adComplete(ty.channel * .ChannelHandlerContext) */Overridepublic void channelReadComplete(ChannelHandlerContext ctx) throws Exception / TODO Auto-generated method stubctx.flush();/ 将队列中的消息写入到SocketChannel发送给客户端/* * (non-Javadoc) * * see * ty.channel.ChannelHandlerAdapter#exceptionCaught(ty.channel *

15、 .ChannelHandlerContext, java.lang.Throwable) */Overridepublic void exceptionCaught(ChannelHandlerContext ctx, Throwable cause)throws Exception / TODO Auto-generated method stubctx.close();/ 关闭，释放资源创建Netty客户端：一创建TimeClient:package ty.demo;import ty.bootstrap.Bootstrap;import ty.channel.ChannelFuture

16、;import ty.channel.ChannelInitializer;import ty.channel.ChannelOption;import ty.channel.ChannelPipeline;import ty.channel.EventLoopGroup;import ty.channel.nio.NioEventLoopGroup;import ty.channel.socket.SocketChannel;import ty.channel.socket.nio.NioSocketChannel;import ty.handler.codec.DelimiterBased

17、FrameDecoder;import ty.handler.codec.Delimiters;import ty.handler.codec.string.StringDecoder;import ty.handler.codec.string.StringEncoder;public class TimeClient public void connect(String host, int port) throws Exception / 配置客户端NIO线程组EventLoopGroup group = new NioEventLoopGroup();try / 创建NIO客户端辅助启动

18、类Bootstrap b = new Bootstrap();b.group(group).channel(NioSocketChannel.class).option(ChannelOption.TCP_NODELAY, true).handler(new ClientTimeHander();/发起异步链接操作ChannelFuture f = b.connect(host, port).sync();/等待客户端链路关闭f.channel().closeFuture().sync(); finally group.shutdownGracefully();/ 关闭 释放资源private

19、 class ClientTimeHander extends ChannelInitializer<SocketChannel> Overrideprotected void initChannel(SocketChannel arg0) throws Exception / TODO Auto-generated method stubChannelPipeline pipeline = arg0.pipeline();/ 以("n")为结尾分割的 解码器pipeline.addLast("framer", new DelimiterBa

20、sedFrameDecoder(8192,Delimiters.lineDelimiter();/ 字符串解码 和 编码pipeline.addLast("decoder", new StringDecoder();pipeline.addLast("encoder", new StringEncoder();/ 自己的逻辑Handlerpipeline.addLast("handler", new TimeClientHander();public static void main(String args) / TODO Auto-

21、generated method stubString host = "localhost"int port = 8080;try new TimeClient().connect(host, port); catch (Exception e) / TODO Auto-generated catch blocke.printStackTrace();二创建TimeClientHander:package ty.demo;import ty.buffer.ByteBuf;import ty.buffer.Unpooled;import ty.channel.ChannelH

22、andlerAdapter;import ty.channel.ChannelHandlerContext;public class TimeClientHander extends ChannelHandlerAdapter private final ByteBuf firstMsg;public TimeClientHander()byte req = "send msg to server date".getBytes();firstMsg = Unpooled.buffer(req.length);firstMsg.writeBytes(req);/* (non-Javadoc) * see ty.channel.ChannelHandlerAdapter#channelActive(ty.channel.ChannelHandlerContext) */Overridepublic void channelActive(ChannelHandlerContext ctx) throws Exception / TODO Auto-generated method stubctx.writeAndFlush(firstMsg);/* (non-Javadoc) * see ty.channel.Chan