基于Netty的RPC架构实战演练(二)-netty3服务端和客户端

一,Netty

 (1)Netty 是由JBOSS提供的一个java开源框架。Netty提供异步的、事件驱动的网络应用程序框架和工具,用以快速开发高性能、高可靠性的网络服务器和客户端程序。

也就是说,Netty 是一个基于NIO的客户、服务器端编程框架,使用Netty 可以确保你快速和简单的开发出一个网络应用,例如实现了某种协议的客户、服务端应用。Netty相当于简化和流线化了网络应用的编程开发过程,例如:基于TCP和UDP的socket服务开发。

“快速”和“简单”并不用产生维护性或性能上的问题。Netty 是一个吸收了多种协议(包括FTP、SMTP、HTTP等各种二进制文本协议)的实现经验,并经过相当精心设计的项目。最终,Netty 成功的找到了一种方式,在保证易于开发的同时还保证了其应用的性能,稳定性和伸缩性。

 

(2)Netty版本大致版本分为  netty3.x  和  netty4.x、netty5.x

 

(3)Netty应用的领域:

1分布式进程通信

例如: hadoop、dubbo、akka等具有分布式功能的框架,底层RPC通信都是基于netty实现的,这些框架使用的版本通常都还在用netty3.x

2、游戏服务器开发

最新的游戏服务器有部分公司可能已经开始采用netty4.x 或 netty5.x

 

二,netty服务端hello world案例

package com.server;

import java.net.InetSocketAddress;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

import org.jboss.netty.bootstrap.ServerBootstrap;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.socket.nio.NioServerSocketChannelFactory;
import org.jboss.netty.handler.codec.string.StringDecoder;
import org.jboss.netty.handler.codec.string.StringEncoder;
/**
 * netty服务端入门
 *
 */
public class Server {

	public static void main(String[] args) {

		//服务类
		ServerBootstrap bootstrap = new ServerBootstrap();
		
		//boss线程监听端口,worker线程负责数据读写
		ExecutorService boss = Executors.newCachedThreadPool();
		ExecutorService worker = Executors.newCachedThreadPool();
		
		//设置niosocket工厂
		bootstrap.setFactory(new NioServerSocketChannelFactory(boss, worker));
		
		//设置管道的工厂
		bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
			
			@Override
			public ChannelPipeline getPipeline() throws Exception {

				ChannelPipeline pipeline = Channels.pipeline();
				pipeline.addLast("decoder", new StringDecoder());
				pipeline.addLast("encoder", new StringEncoder());
				pipeline.addLast("helloHandler", new HelloHandler());
				return pipeline;
			}
		});
		
		bootstrap.bind(new InetSocketAddress(10101));
		
		System.out.println("start!!!");
		
	}

}
package com.server;

import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelHandler;
/**
 * 消息接受处理类
 *
 */
public class HelloHandler extends SimpleChannelHandler {

	/**
	 * 接收消息
	 */
	@Override
	public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {

		
		String s = (String) e.getMessage();
		System.out.println(s);
		
		//回写数据
		ctx.getChannel().write("hi");
		super.messageReceived(ctx, e);
	}

	/**
	 * 捕获异常
	 */
	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {
		System.out.println("exceptionCaught");
		super.exceptionCaught(ctx, e);
	}

	/**
	 * 新连接,通常用来检测IP是否是黑名单
	 */
	@Override
	public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
		System.out.println("channelConnected");
		super.channelConnected(ctx, e);
	}

	/**
	 * 必须是链接已经建立,关闭通道的时候才会触发
	 */
	@Override
	public void channelDisconnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
		System.out.println("channelDisconnected");
		super.channelDisconnected(ctx, e);
	}

	/**
	 * channel关闭的时候触发,可以再用户断线的时候清楚用户的缓存数据等
	 */
	@Override
	public void channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
		System.out.println("channelClosed");
		super.channelClosed(ctx, e);
	}
}

三,netty客户端hello world案例

package com.client;

import java.net.InetSocketAddress;
import java.util.Scanner;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import org.jboss.netty.bootstrap.ClientBootstrap;
import org.jboss.netty.channel.Channel;
import org.jboss.netty.channel.ChannelFuture;
import org.jboss.netty.channel.ChannelPipeline;
import org.jboss.netty.channel.ChannelPipelineFactory;
import org.jboss.netty.channel.Channels;
import org.jboss.netty.channel.socket.nio.NioClientSocketChannelFactory;
import org.jboss.netty.handler.codec.string.StringDecoder;
import org.jboss.netty.handler.codec.string.StringEncoder;
/**
 * netty客户端入门
 *
 */
public class Client {

	public static void main(String[] args) {
		
		//服务类
		ClientBootstrap bootstrap = new  ClientBootstrap();
		
		//线程池
		ExecutorService boss = Executors.newCachedThreadPool();
		ExecutorService worker = Executors.newCachedThreadPool();
		
		//socket工厂
		bootstrap.setFactory(new NioClientSocketChannelFactory(boss, worker));
		
		//管道工厂
		bootstrap.setPipelineFactory(new ChannelPipelineFactory() {
			
			@Override
			public ChannelPipeline getPipeline() throws Exception {
				ChannelPipeline pipeline = Channels.pipeline();
				pipeline.addLast("decoder", new StringDecoder());
				pipeline.addLast("encoder", new StringEncoder());
				pipeline.addLast("hiHandler", new HiHandler());
				return pipeline;
			}
		});
		
		//连接服务端
		ChannelFuture connect = bootstrap.connect(new InetSocketAddress("127.0.0.1", 10101));
		Channel channel = connect.getChannel();
		
		System.out.println("client start");
		
		Scanner scanner = new Scanner(System.in);
		while(true){
			System.out.println("请输入");
			channel.write(scanner.next());
		}
	}

}
package com.client;

import org.jboss.netty.channel.ChannelHandlerContext;
import org.jboss.netty.channel.ChannelStateEvent;
import org.jboss.netty.channel.ExceptionEvent;
import org.jboss.netty.channel.MessageEvent;
import org.jboss.netty.channel.SimpleChannelHandler;
/**
 * 消息接受处理类
 *
 */
public class HiHandler extends SimpleChannelHandler {

	/**
	 * 接收消息
	 */
	@Override
	public void messageReceived(ChannelHandlerContext ctx, MessageEvent e) throws Exception {

		
		String s = (String) e.getMessage();
		System.out.println(s);
		
		super.messageReceived(ctx, e);
	}

	/**
	 * 捕获异常
	 */
	@Override
	public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e) throws Exception {
		System.out.println("exceptionCaught");
		super.exceptionCaught(ctx, e);
	}

	/**
	 * 新连接
	 */
	@Override
	public void channelConnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
		System.out.println("channelConnected");
		super.channelConnected(ctx, e);
	}

	/**
	 * 必须是链接已经建立,关闭通道的时候才会触发
	 */
	@Override
	public void channelDisconnected(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
		System.out.println("channelDisconnected");
		super.channelDisconnected(ctx, e);
	}

	/**
	 * channel关闭的时候触发
	 */
	@Override
	public void channelClosed(ChannelHandlerContext ctx, ChannelStateEvent e) throws Exception {
		System.out.println("channelClosed");
		super.channelClosed(ctx, e);
	}
}

备注:

channelDisconnected与channelClosed的区别?

channelDisconnected只有在连接建立后断开才会调用

channelClosed无论连接是否成功都会调用关闭资源

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