标签:通信 client erb 易用 根据 channel tin package 绑定
一、简介
Netty是基于Java NIO client-server的网络应用框架,使用Netty可以快速开发网络应用,例如服务器和客户端协议。Netty提供了一种新的方式来开发网络应用程序,这种新的方式使它很容易使用和具有很强的扩展性。Netty的内部实现是很复杂的,但是Netty提供了简单易用的API从网络处理代码中解耦业务逻辑。Netty是完全基于NIO实现的,所以整个Netty都是异步的。
网络应用程序通常需要有较高的可扩展性,无论是Netty还是其他的基于Java Nio的框架,都会提供可扩展性的解决方案。Netty中一个关键组成部分是它的异步特性,本片文章将讨论同步(阻塞)和异步(非阻塞)的IO来说明为什么使用异步代码解决扩展性问题以及如何使用异步。
二、入门程序
2.1创建服务端
2.1.1创建HelloServer
package com.zy.netty.example; import io.netty.bootstrap.ServerBootstrap; import io.netty.channel.ChannelFuture; import io.netty.channel.EventLoopGroup; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.nio.NioServerSocketChannel; public class HelloServer { /** * 服务端监听的端口地址 */ private static final int portNumber = 7878; public static void main(String[] args) throws InterruptedException { EventLoopGroup bossGroup = new NioEventLoopGroup(); EventLoopGroup workerGroup = new NioEventLoopGroup(); try { ServerBootstrap b = new ServerBootstrap(); b.group(bossGroup, workerGroup); b.channel(NioServerSocketChannel.class); b.childHandler(new HelloServerInitializer()); // 服务器绑定端口监听 ChannelFuture f = b.bind(portNumber).sync(); // 监听服务器关闭监听 f.channel().closeFuture().sync(); // 可以简写为 /* b.bind(portNumber).sync().channel().closeFuture().sync(); */ } finally { bossGroup.shutdownGracefully(); workerGroup.shutdownGracefully(); } } }
2.1.2创建和实现HelloServerInitializer
package com.zy.netty.example; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; import io.netty.handler.codec.DelimiterBasedFrameDecoder; import io.netty.handler.codec.Delimiters; import io.netty.handler.codec.string.StringDecoder; import io.netty.handler.codec.string.StringEncoder; public class HelloServerInitializer extends ChannelInitializer<SocketChannel> { @Override protected void initChannel(SocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.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 StringEncoder()); // 自己的逻辑Handler pipeline.addLast("handler", new HelloServerHandler()); } }
2.1.3创建ServerHandler
package com.zy.netty.example; import java.net.InetAddress; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; public class HelloServerHandler extends SimpleChannelInboundHandler<String> { /* @Override protected void channelRead(ChannelHandlerContext ctx, String msg) throws Exception { // 收到消息直接打印输出 System.out.println(ctx.channel().remoteAddress() + " Say : " + msg); // 返回客户端消息 - 我已经接收到了你的消息 ctx.writeAndFlush("Received your message !\n"); }*/ /* * * 覆盖 channelActive 方法 在channel被启用的时候触发 (在建立连接的时候) * * channelActive 和 channelInActive 在后面的内容中讲述,这里先不做详细的描述 */ @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { System.out.println("RamoteAddress : " + ctx.channel().remoteAddress() + " active !"); ctx.writeAndFlush("Welcome to " + InetAddress.getLocalHost().getHostName() + " service!\n"); super.channelActive(ctx); } @Override protected void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception { System.out.println(ctx.channel().remoteAddress() + " Say : " + msg); // 返回客户端消息 - 我已经接收到了你的消息 ctx.writeAndFlush("Received your message !\n"); } }
2.2Client客户端
2.2.1创建HelloClient
package com.zy.netty.example; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import io.netty.bootstrap.Bootstrap; import io.netty.channel.Channel; import io.netty.channel.EventLoopGroup; import io.netty.channel.nio.NioEventLoopGroup; import io.netty.channel.socket.nio.NioSocketChannel; public class HelloClient { public static String host = "127.0.0.1"; public static int port = 7878; /** * @param args * @throws InterruptedException * @throws IOException */ public static void main(String[] args) throws InterruptedException, IOException { EventLoopGroup group = new NioEventLoopGroup(); try { Bootstrap b = new Bootstrap(); b.group(group).channel(NioSocketChannel.class).handler(new HelloClientInitializer()); // 连接服务端 Channel ch = b.connect(host, port).sync().channel(); // 控制台输入 BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); for (;;) { String line = in.readLine(); if (line == null) { continue; } /* * 向服务端发送在控制台输入的文本 并用"\r\n"结尾 之所以用\r\n结尾 是因为我们在handler中添加了 * DelimiterBasedFrameDecoder 帧解码。 * 这个解码器是一个根据\n符号位分隔符的解码器。所以每条消息的最后必须加上\n否则无法识别和解码 */ ch.writeAndFlush(line + "\r\n"); } } finally { // The connection is closed automatically on shutdown. group.shutdownGracefully(); } } }
2.2.2创建和实现HelloClientInitalizer
package com.zy.netty.example; import io.netty.channel.ChannelInitializer; import io.netty.channel.ChannelPipeline; import io.netty.channel.socket.SocketChannel; import io.netty.handler.codec.DelimiterBasedFrameDecoder; import io.netty.handler.codec.Delimiters; import io.netty.handler.codec.string.StringDecoder; import io.netty.handler.codec.string.StringEncoder; public class HelloClientInitializer extends ChannelInitializer<SocketChannel>{ @Override protected void initChannel(SocketChannel ch) throws Exception { ChannelPipeline pipeline = ch.pipeline(); /* * 这个地方的 必须和服务端对应上。否则无法正常解码和编码 * * 解码和编码 我将会在下一张为大家详细的讲解。再次暂时不做详细的描述 * * */ pipeline.addLast("framer", new DelimiterBasedFrameDecoder(8192, Delimiters.lineDelimiter())); pipeline.addLast("decoder", new StringDecoder()); pipeline.addLast("encoder", new StringEncoder()); // 客户端的逻辑 pipeline.addLast("handler", new HelloClientHandler()); } }
2.2.3创建ClientHandler
package com.zy.netty.example; import io.netty.channel.ChannelHandlerContext; import io.netty.channel.SimpleChannelInboundHandler; public class HelloClientHandler extends SimpleChannelInboundHandler<String> { /* * @Override protected void channelRead0(ChannelHandlerContext ctx, String * msg) throws Exception { * * System.out.println("Server say : " + msg); } */ @Override public void channelActive(ChannelHandlerContext ctx) throws Exception { System.out.println("Client active "); super.channelActive(ctx); } @Override public void channelInactive(ChannelHandlerContext ctx) throws Exception { System.out.println("Client close "); super.channelInactive(ctx); } @Override protected void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception { System.out.println("Server say : " + msg); } }
以上例子是一个最简单的服务端和客户端通信的模型,主要原理是服务端和客户端监听同一个ip的端口,监听到信息作出相应的反应
标签:通信 client erb 易用 根据 channel tin package 绑定
原文地址:https://www.cnblogs.com/zyxiaohuihui/p/9093137.html