NettyServer Client

1. NettyServer端配置

javaIO==>NIO===>Netty

package com.example.demo;

import io.netty.bootstrap.ServerBootstrap;
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.NioServerSocketChannel;

public class Server {

    public static void main(String[] args) throws InterruptedException {
        
        //NettyServer端配置流程
        //1. 创建boosgroup和workergroup
   //2. Bossgroup只是负责处理连接请求，真正和客户端处理业务会交给workergro8up完成
            EventLoopGroup bossGroup =new NioEventLoopGroup();
            EventLoopGroup workerGroup =new NioEventLoopGroup();
            
        //3.配置启动参数,
            ServerBootstrap bootstrap = new ServerBootstrap();
            
        //4.用链式编程来进行设置
            bootstrap.group(bossGroup,workerGroup) //设置两个线程组
            .channel(NioServerSocketChannel.class) //使用NioSokectChannel作为服务器的通道实现
            .option(ChannelOption.SO_BACKLOG, 128) //设置线程队列到底连接个数
            .childOption(ChannelOption.SO_KEEPALIVE, true)  //设置保持活动连接状态
            .childHandler(new ChannelInitializer<SocketChannel>() { //创建一个通道测试对象（匿名对象）
                //给pipeline设置处理器
                @Override
                protected void initChannel(SocketChannel ch) throws Exception {
                     ch.pipeline().addLast(null);
                    
                }
            }) ;//给workergroup的Eventloop管道设置处理器
            
            System.out.println("。。。。服务器已经准备好");
            
            //5. 绑定一个端口病同步，生成一个channelFuture对象.
            // 启动服务器，并绑定端口.
            ChannelFuture cf = bootstrap.bind(6668).sync();
            
            //6.对关闭通道进行监听
            cf.channel().closeFuture().sync();
    }
}

package com.example.demo;

import io.netty.bootstrap.ServerBootstrap;
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.NioServerSocketChannel;

public class Server {

    public static void main(String[] args) throws InterruptedException {
        
        //NettyServer端配置流程
        //1. 创建boosgroup和workergroup
        //2. Bossgroup只是负责处理连接请求，真正和客户端处理业务会交给workergro8up完成
            EventLoopGroup bossGroup =new NioEventLoopGroup();
            EventLoopGroup workerGroup =new NioEventLoopGroup();
        
            try {
        
        //3.配置启动参数,
            ServerBootstrap bootstrap = new ServerBootstrap();
            
        //4.用链式编程来进行设置
            bootstrap.group(bossGroup,workerGroup) //设置两个线程组
            .channel(NioServerSocketChannel.class) //使用NioSokectChannel作为服务器的通道实现
            .option(ChannelOption.SO_BACKLOG, 128) //设置线程队列到底连接个数
            .childOption(ChannelOption.SO_KEEPALIVE, true)  //设置保持活动连接状态
            .childHandler(new ChannelInitializer<SocketChannel>() { //创建一个通道测试对象（匿名对象）
                //给pipeline设置处理器
                @Override
                protected void initChannel(SocketChannel ch) throws Exception {
                     ch.pipeline().addLast(new NettyClientHandler());
                    
                }
            }) ;//给workergroup的Eventloop管道设置处理器
            
            System.out.println("。。。。服务器已经准备好");
            
            //5. 绑定一个端口病同步，生成一个channelFuture对象.
            // 启动服务器，并绑定端口.
            ChannelFuture cf = bootstrap.bind(6668).sync();
            
            //6.对关闭通道进行监听
            cf.channel().closeFuture().sync();
     
            } catch (Exception e) {
                 e.printStackTrace();
            }finally {
            bossGroup.shutdownGracefully();
            workerGroup.shutdownGracefully();
            }
        
}

2.ServerHandler

package com.example.demo;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;


//1. 我们自定义一个handler 需要继续netty规定好的某个handleradapter.
//2. 这是我们的自定义一个handler，才能称之为一个handler
public class ServerHandler extends ChannelInboundHandlerAdapter{
    
    //读取客户端发送的消息.
    //1. channelhandlercontext  ctx 上下文对象 ，含有管道pipline ， 通道channel ,地址
    //2. object msg :就是客户端发送的数据 ，默认是object
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {


        System.out.println("server ctx ="+ ctx);
        //将msg转成一个bytebuf
        //ByteBuf 是netty提供的，不是NIO的ByteBuffer
        ByteBuf buf =(ByteBuf) msg;
        System.out.println("客户端发送消息是"+ buf.toString(CharsetUtil.UTF_8));
        System.out.println("客户端地址是"+ctx.channel().remoteAddress());
         
        
    }
    
    //数据读取完毕
    @Override
    public void channelReadComplete(ChannelHandlerContext ctx) throws Exception {
        
        //将数据写入缓存，并刷新.
        //对发送的数据发送编码
        ctx.writeAndFlush(Unpooled.copiedBuffer("hello, 客户端",CharsetUtil.UTF_8));
    }
    
    //处理异常,一般是需要关闭通道.
    //最后，把handler加入到pipeline中.
    @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
        ctx.close(); 
    }
}

3. Client

package com.example.demo;

import io.netty.bootstrap.Bootstrap;
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.SocketChannel;
import io.netty.channel.socket.nio.NioSocketChannel;

public class NettyClient {
    public static void main(String[] args) throws Exception {

        // 客户端需要一个事件循环组
        EventLoopGroup group = new NioEventLoopGroup();
        try {

            // 创建客户端启动对象
            // 注意客户端不是serverbootstrap 而是Bootstrap
            Bootstrap bootstrap = new Bootstrap();

            // 设置相关参数
            bootstrap.group(group)// 设置线程组
                    .channel(NioSocketChannel.class)// 设置客户端的实现类(反射)
                    .handler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ch.pipeline().addLast(new NettyClientHandler()); // 加入自己的处理器

                        }
                    });
            System.out.println("客户端 ok ");
            // 启动客户端去连接服务器端
            // 关于channelFuture 要分析，设计到netty的异步模型.
            ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 6668).sync();

            // 给关闭通道进行监听
            channelFuture.channel().closeFuture().sync();

        } finally {
            group.shutdownGracefully();
        }

    }
}

4.ClientHandler

package com.example.demo;

import java.nio.charset.Charset;

import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.util.CharsetUtil;

public class NettyClientHandler extends ChannelInboundHandlerAdapter {
    
    
    //当通道就绪就会触发该方法
    @Override
    public void channelActive(ChannelHandlerContext ctx) throws Exception {
        
        System.out.println("client" + ctx);
        
        ctx.writeAndFlush(Unpooled.copiedBuffer("hello,server你好...... ",CharsetUtil.UTF_8));
                
    }
        
    //当通道有读取事件的时候，会触发
    @Override
    public void channelRead(ChannelHandlerContext ctx, Object msg) throws Exception {
             
        ByteBuf buf =(ByteBuf) msg;
        System.out.println("服务器发送回复的消息:"+ buf.toString(CharsetUtil.UTF_8));
        System.out.println("服务器的地址:"+ ctx.channel().remoteAddress());
               
    }
        @Override
    public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
         cause.printStackTrace();
         ctx.close();
    }
}