Netty【UDP】服务器解析【自定义协议】

最近在做RFID定位的项目，为了方便自主开发2.4G读写器和数据服务器。服务端采用Netty。

协议描述：

1. 标签ID数据上传：读写器设备按设定时间频率更新读到的所有电子标签的ID号，并向上位机主动发送数据(用UDP模式) 

设备ID(2Byte = 0-65535) + 'A' + Sn(1Byte = 0-255) + 标签数(1Byte = n) + 标签1(3Byte = 0x00,0x2A,0x3B)+ 标签2(3Byte = 0x01,0x2b,0x3c)+....+标签n(3Byte = 0x00,0x23,0x6B) + CheckSum(1Byte)

package com.netty;import java.net.InetSocketAddress;import org.jboss.netty.bootstrap.ConnectionlessBootstrap;import org.jboss.netty.channel.ChannelPipeline;import org.jboss.netty.channel.ChannelPipelineFactory;import org.jboss.netty.channel.Channels;import org.jboss.netty.channel.socket.DatagramChannelFactory;import org.jboss.netty.channel.socket.nio.NioDatagramChannelFactory;public class UdpServer {private ConnectionlessBootstrap udpBootstrap;public UdpServer(int port){DatagramChannelFactory channelFactory = new NioDatagramChannelFactory();udpBootstrap = new ConnectionlessBootstrap(channelFactory);udpBootstrap.setPipelineFactory(new ChannelPipelineFactory() {public ChannelPipeline getPipeline() throws Exception {return Channels.pipeline(new UdpEventHandler());}});udpBootstrap.bind(new InetSocketAddress(port));}public static void main(String[] args) {new UdpServer(32500);}}

package com.netty;import java.nio.ByteBuffer;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 UdpEventHandler extends SimpleChannelUpstreamHandler {@Overridepublic void exceptionCaught(ChannelHandlerContext arg0, ExceptionEvent arg1)throws Exception {super.exceptionCaught(arg0, arg1);}private ChannelBuffer buffer;private ByteBuffer byteBuffer;private byte[] arrayByte;private int deviceID ;//设备IDprivate int cmd;//命令类型private int sn;private int count ;//标签数private int tag;//标签号private int checkSum ;//校验和private int tagType;//标签类型@Overridepublic void messageReceived(ChannelHandlerContext ctx, MessageEvent e)throws Exception {super.messageReceived(ctx, e);buffer = (ChannelBuffer)e.getMessage();byteBuffer = buffer.copy().toByteBuffer();arrayByte = byteBuffer.array();if(  !(arrayByte!= null && arrayByte.length >=14) ){return ;}deviceID = toInt(arrayByte[6]);deviceID = (deviceID<<8) + toInt(arrayByte[7]);cmd =  toInt(arrayByte[8]);sn = toInt(arrayByte[9]);count = toInt(arrayByte[10]);if((char)cmd == 'A' ){if(count == 0 )return  ;checkSum = toInt(arrayByte[11+(count*3)]);//上报标签for(int i=0;i<count;i++){tagType = toInt(arrayByte[11+(i*3)]);tag = toInt(arrayByte[11+(i*3)+1]);tag = (tag<<8) +toInt(arrayByte[11+(i*3)+2]);//插入数据库}}else if ((char)cmd == 'B'){//无标签上报心跳包     }}//取正       private   int   toInt(byte   b){               if(b   >=   0)   return   (int)b;               else               return   (int)(b   +   256);       }   }