netty 3.9.2 UDP协议服务器和客户端DEMO

2022-11-18 12:44:52

说明：基于netty 3.9.2的udp协议实现的（如果你使用的版本是4.X或5.X，请参考其他方法）；程序的逻辑结构是，客户端发送给服务端一串数据，服务器端返回给客户端“A”。在进行游戏开发时需要对udp的丢包进行处理，可以利用服务器端的返回值进行相关处理，以确定是否重发，这方面具体没有实现。

文章结构：

一、服务器端

1、UDPServer

2、UdpChannelPipelineFactory

3、UDPServerHandler

二、客户端

1、UDPClient

2、UDPClientChannelPipelineFactory

3、UDPClientHandler

三、ScanGetPort获取一个可用的端口号

一、服务器端

1、UDPServer

初始化一个ConnectionlessBootstrap，setPipelineFactory，绑定一个端口号。ScanGetPort是一个工具类就是，获取一个可用的端口号，源代码在最后面贴出。

package com.ls.udp.server;

import java.net.InetSocketAddress;

import java.util.concurrent.Executors;

import org.jboss.netty.bootstrap.ConnectionlessBootstrap;

import org.jboss.netty.channel.socket.nio.NioDatagramChannelFactory;

import com.andy.server.util.ScanGetPort;

public class UDPServer {

    public final int PORT;

    public UDPServer(int port){

        PORT=port;

    }

    private ConnectionlessBootstrap  bootstrap;

    void start(){

        //init the bootstrap

        bootstrap=new ConnectionlessBootstrap(new NioDatagramChannelFactory(Executors.newCachedThreadPool()));

        bootstrap.setPipelineFactory(new UdpChannelPipelineFactory());

        bootstrap.bind(new InetSocketAddress(PORT));

        System.out.println("server start at:"+":"+PORT);

    }

    public static void main(String[] args) {

        /*

         * 获取一个可用的端口号

         */

        int port= new ScanGetPort().getPot(8080);

        new UDPServer(port).start();

    }

}

2、UdpChannelPipelineFactory

注册一个handler

package com.ls.udp.server;

import org.jboss.netty.channel.ChannelPipeline;

import org.jboss.netty.channel.ChannelPipelineFactory;

import org.jboss.netty.channel.Channels;

public class UdpChannelPipelineFactory implements ChannelPipelineFactory{

    /**

     * set the channel pipeline

     *

     */

    @Override

    public ChannelPipeline getPipeline() throws Exception {

        ChannelPipeline pipeline = Channels.pipeline();

        pipeline.addLast("handler", new UDPServerHandler());

        return pipeline;

    }

}

3、UDPServerHandler

handler类

package com.ls.udp.server;

import org.jboss.netty.buffer.ChannelBuffer;

import org.jboss.netty.buffer.DynamicChannelBuffer;

import org.jboss.netty.channel.ChannelHandlerContext;

import org.jboss.netty.channel.ExceptionEvent;

import org.jboss.netty.channel.MessageEvent;

import org.jboss.netty.channel.SimpleChannelUpstreamHandler;

public class UDPServerHandler extends SimpleChannelUpstreamHandler{

    /**

     *  对于ChannelHandler，

     *  是UDP与TCP区别的核心所在。

     *  大家都知道UDP是无连接的，

     *  也就是说你通过 MessageEvent 参数对象的 getChannel() 方法获取当前会话连接，

     *  但是其 isConnected() 永远都返回 false。

     *  UDP 开发中在消息获取事件回调方法中，

     *  获取了当前会话连接 channel 对象后可直接通过 channel 的 write 方法发送数据给对端 channel.write(message, remoteAddress)，

     *  第一个参数仍然是要发送的消息对象，

     *  第二个参数则是要发送的对端 SocketAddress 地址对象。

     *  这里最需要注意的一点是SocketAddress，在TCP通信中我们可以通过channel.getRemoteAddress()获得，

     *  但在UDP通信中，我们必须从MessageEvent中通过调用getRemoteAddress()方法获得对端的SocketAddress 地址。

     */

    @Override

    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e)

            throws Exception {

        ChannelBuffer buffer = (ChannelBuffer)e.getMessage();

        byte[] recByte=buffer.copy().toByteBuffer().array();

        String msg=new String(recByte);

        System.out.println("from client:"+msg);

        ChannelBuffer responseBuffer= new DynamicChannelBuffer(1);

        responseBuffer.writeBytes("A".getBytes());

        //write to the client

        e.getChannel().write(responseBuffer, e.getRemoteAddress());

        super.messageReceived(ctx, e);

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e)

            throws Exception {

        super.exceptionCaught(ctx, e);

    }

}

二、客户端

（基本结构和服务器端很像，不再赘述）

1、UDPClient

package com.ls.udp.client;

import java.net.InetSocketAddress;

import java.util.Scanner;

import org.jboss.netty.bootstrap.ConnectionlessBootstrap;

import org.jboss.netty.buffer.ChannelBuffer;

import org.jboss.netty.buffer.DynamicChannelBuffer;

import org.jboss.netty.channel.Channel;

import org.jboss.netty.channel.socket.nio.NioDatagramChannelFactory;

public class UDPClient {

    private ConnectionlessBootstrap  bootstrap;

    private Channel channel;

    public void start(){

        //init the bootstrap

        bootstrap=new ConnectionlessBootstrap(new NioDatagramChannelFactory());

        bootstrap.setPipelineFactory(new UDPClientChannelPipelineFactory());

        bootstrap.setOption("localAddress", new InetSocketAddress(10001));

        channel=bootstrap.bind();

    }

    public void writebytes(byte[] bt,InetSocketAddress isa){

        if(bootstrap==null){

            this.start();

        }

        ChannelBuffer responseBuffer= new DynamicChannelBuffer(12);

        responseBuffer.writeBytes(bt);

        channel.write(responseBuffer, isa);

    }

    public static void main(String[] args) {

        UDPClient uClient=new UDPClient();

        Scanner scanner=new Scanner(System.in);

        String lienString=scanner.nextLine();

        while(!lienString.equals("bye")){

            uClient.writebytes(lienString.getBytes(), new InetSocketAddress("192.168.1.107",8080));

            lienString=scanner.nextLine();

        }

    }

}

2、UDPClientChannelPipelineFactory

package com.ls.udp.client;

import org.jboss.netty.channel.ChannelPipeline;

import org.jboss.netty.channel.ChannelPipelineFactory;

import org.jboss.netty.channel.Channels;

public class UDPClientChannelPipelineFactory implements ChannelPipelineFactory{

    /**

     * set the channel pipeline

     *

     */

    @Override

    public ChannelPipeline getPipeline() throws Exception {

        ChannelPipeline pipeline = Channels.pipeline();

        pipeline.addLast("handler", new UDPClientHandler());

        return pipeline;

    }

}

3、UDPClientHandler

package com.ls.udp.client;

import org.jboss.netty.buffer.ChannelBuffer;

import org.jboss.netty.channel.ChannelHandlerContext;

import org.jboss.netty.channel.ExceptionEvent;

import org.jboss.netty.channel.MessageEvent;

import org.jboss.netty.channel.SimpleChannelUpstreamHandler;

public class UDPClientHandler extends SimpleChannelUpstreamHandler{

    @Override

    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e)

            throws Exception {

        ChannelBuffer buffer = (ChannelBuffer)e.getMessage();

        byte[] recByte=buffer.copy().toByteBuffer().array();

        String msg=new String(recByte);

        System.out.println("from server:"+msg);

        super.messageReceived(ctx, e);

    }

    @Override

    public void exceptionCaught(ChannelHandlerContext ctx, ExceptionEvent e)

            throws Exception {

        super.exceptionCaught(ctx, e);

    }

}

三、ScanGetPort获取一个可用的端口号

package com.andy.server.util;

import java.io.IOException;

import java.net.ServerSocket;

/**

 * get the port

 * @author red

 *

 */

public class ScanGetPort {

    public synchronized  int  getPot(int first){

        for(int i=first;i<65535;++i){

            ServerSocket ss=null;

            try {

                 ss= new ServerSocket(i);

            } catch (IOException e) {

                //e.printStackTrace();

            }finally{

                if(ss!=null){

                    if(ss.isBound()){

                        try {

                            ss.close();

                            System.out.println(i);

                            return i;

                        } catch (IOException e) {

                            e.printStackTrace();

                        }

                    }

                }

            }

        }

        return -1;

    }

}

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