netty4----netty5的客户端和服务端

时间:2022-05-16 13:06:25

服务端:

package com.server;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.Channel;
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.nio.NioServerSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

/**
 * netty5版本服务端
 */
public class Server {

    public static void main(String[] args) {
        //服务类
        ServerBootstrap bootstrap = new ServerBootstrap();
        
        //boss和worker, netty5不是线程池,而是事件循环组,里面包含线程池。
        EventLoopGroup boss = new NioEventLoopGroup();
        EventLoopGroup worker = new NioEventLoopGroup();
        
        try {
            //设置线程池
            bootstrap.group(boss, worker);//boss用来监听端口的
            
            //设置socket工厂、
            bootstrap.channel(NioServerSocketChannel.class);
            
            //设置管道工厂
            bootstrap.childHandler(new ChannelInitializer<Channel>() {

                @Override
                protected void initChannel(Channel ch) throws Exception {
                    ch.pipeline().addLast(new StringDecoder());
                    ch.pipeline().addLast(new StringEncoder());
                    ch.pipeline().addLast(new ServerHandler());
                }
            });
            
            //netty3中对应设置如下
            //bootstrap.setOption("backlog", 1024);
            //bootstrap.setOption("tcpNoDelay", true);
            //bootstrap.setOption("keepAlive", true);
            //设置参数,TCP参数
            bootstrap.option(ChannelOption.SO_BACKLOG, 2048);//serverSocketchannel的设置,链接缓冲池的大小。tcp的服务端是有队列的。队列保存2048个客户端。2048后面的连接是拒绝的。
            bootstrap.childOption(ChannelOption.SO_KEEPALIVE, true);//socketchannel的设置,维持链接的活跃,清除死链接
            bootstrap.childOption(ChannelOption.TCP_NODELAY, true);//socketchannel的设置,关闭延迟发送。发一包并不是马上发出去,而是积累到一定之后再发出去。
            
            //绑定端口
            ChannelFuture future = bootstrap.bind(10101);
            
            System.out.println("start");
            
            //等待服务端关闭
            future.channel().closeFuture().sync();
            
        } catch (Exception e) {
            e.printStackTrace();
        } finally{
            //释放资源
            boss.shutdownGracefully();
            worker.shutdownGracefully();
        }
    }
}
package com.server;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
/**
 * 服务端消息处理
 */
public class ServerHandler extends SimpleChannelInboundHandler<String> {

    @Override
    protected void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception {
        System.out.println(msg);
        ctx.channel().writeAndFlush("hi");
        ctx.writeAndFlush("hi");
    }

    /**
     * 新客户端接入
     */
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channelActive");
    }

    /**
     * 客户端断开
     */
    @Override
    public void channelInactive(ChannelHandlerContext ctx) throws Exception {
        System.out.println("channelInactive");
    }

    /**
     * 异常
     */
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        cause.printStackTrace();
    }
    
    
}

客户端:

package com.client;

import java.io.BufferedReader;
import java.io.InputStreamReader;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

/**
 * netty5版本的客户端
 */
public class Client {

    public static void main(String[] args) {
        //服务类
        Bootstrap bootstrap = new Bootstrap();
        //worker
        EventLoopGroup worker = new NioEventLoopGroup();//boss用来监听端口,这里只创建worker
        try {
            //设置线程池
            bootstrap.group(worker);
            //设置socket工厂、
            bootstrap.channel(NioSocketChannel.class);
            //设置管道
            bootstrap.handler(new ChannelInitializer<Channel>() {
                @Override
                protected void initChannel(Channel ch) throws Exception {
                    ch.pipeline().addLast(new StringDecoder());
                    ch.pipeline().addLast(new StringEncoder());
                    ch.pipeline().addLast(new ClientHandler());
                }
            });
            ChannelFuture connect = bootstrap.connect("127.0.0.1", 10101);
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
            while(true){
                System.out.println("请输入:");
                String msg = bufferedReader.readLine();
                connect.channel().writeAndFlush(msg);
            }
        } catch (Exception e) {
             e.printStackTrace();
        } finally{
            worker.shutdownGracefully();
        }
    }
}
package com.client;

import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.SimpleChannelInboundHandler;
/**
 * 客户端消息处理
 */
public class ClientHandler extends SimpleChannelInboundHandler<String> {
    @Override
    protected void messageReceived(ChannelHandlerContext ctx, String msg) throws Exception {
        System.out.println("客户端收到消息:"+msg);
    }

}

一个客户端启动多个连接:

package com.client;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.atomic.AtomicInteger;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;

/**
 多连接客户端,客户端保持一个连接不够,要保持多个连接。
  
  线程池是有多个线程,每个线程里面有一个任务队列,线程run的时候会从任务队列取一个任务出来,执行任务的run方法,
  队列里面没有任务就阻塞等待新的任务进来。
  
  一个thread + 队列 == 一个单线程线程池   =====> 线程安全的,任务是线性串行执行的
  
  
  
 对象池:首先初始化n个对象,把这些对象放入一个队列里面,需要对象的时候会出栈一个对象,有对象就出栈,使用完了归还对象池里面。
没有对象会阻塞等待有可用的对象。或者创建一个新的对象使用完之后归还线程池,归还的时候如果池子满了就销毁。
比如数据库连接池:使用完后要释放资源,就是把连接放回连接池里面。


 对象组:首先初始化n个对象,把这些对象放入一个数组里面。使用的时候获取一个对象不移除,使用完之后不用归还。需要对象有并发的能力。
 
 
 
对象组:线程安全,不会产生阻塞效应
对象池:线程不安全,会产生阻塞效应
 */
public class MultClient {
    
    /**
     * 服务类
     */
    private Bootstrap bootstrap = new Bootstrap();
    
    /**
     * 会话,多个channel,
     */
    private List<Channel> channels = new ArrayList<>();
    
    /**
     * 引用计数
     */
    private final AtomicInteger index = new AtomicInteger();
    
    /**
     * 初始化
     * @param count
     */
    public void init(int count){
        
        //worker
        EventLoopGroup worker = new NioEventLoopGroup();
        
        //设置线程池
        bootstrap.group(worker);
        
        //设置socket工厂、
        bootstrap.channel(NioSocketChannel.class);
        
        //设置管道
        bootstrap.handler(new ChannelInitializer<Channel>() {

            @Override
            protected void initChannel(Channel ch) throws Exception {
                ch.pipeline().addLast(new StringDecoder());
                ch.pipeline().addLast(new StringEncoder());
                ch.pipeline().addLast(new ClientHandler());
            }
        });
        
        for(int i=1; i<=count; i++){
            ChannelFuture future = bootstrap.connect("192.168.0.103", 10101);
            channels.add(future.channel());
        }
    }
    
    /**
     * 获取会话
     */
    public Channel nextChannel(){
        return getFirstActiveChannel(0);
    }
    
    
    private Channel getFirstActiveChannel(int count){
        Channel channel = channels.get(Math.abs(index.getAndIncrement() % channels.size()));
        if(!channel.isActive()){
            //重连
            reconnect(channel);
            if(count >= channels.size()){
                throw new RuntimeException("no can use channel");
            }
            return getFirstActiveChannel(count + 1);
        }
        return channel;
    }
    
    /**
     * 重连
     * @param channel
     */
    private void reconnect(Channel channel){
        synchronized(channel){
            if(channels.indexOf(channel) == -1){//已经重连过了
                return ;
            }
            Channel newChannel = bootstrap.connect("192.168.0.103", 10101).channel();
            channels.set(channels.indexOf(channel), newChannel);
        }
    }
}
package com.client;

import java.io.BufferedReader;
import java.io.InputStreamReader;
/**
 * 启动类
 */
public class Start {

    public static void main(String[] args) {

        MultClient client = new MultClient();
        client.init(5);//初始化5个连接
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        while(true){
            try {
                System.out.println("请输入:");
                String msg = bufferedReader.readLine();
                client.nextChannel().writeAndFlush(msg);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

}