java解析JT808协议的实现代码

目录

• 1 JT808协议扫盲
• 1.1 数据类型
• 1.2 消息结构
• 1.3 消息头
• 2 解析
• 2.1 消息体实体类
• 2.2 字节数组到消息体实体类的转换
• 2.3 和netty结合
• 3 demo级别java示例

本篇文章将介绍JT808协议的解析思路。
另请大神绕路，不喜勿喷！
先写个大致的思路,有疑问可以联系本人，联系方式：

emial: hylexus@163.com

1 JT808协议扫盲

1.1 数据类型

1.2 消息结构

1.3 消息头

消息ID(0-1)   消息体属性(2-3) 终端手机号(4-9) 消息流水号(10-11)    消息包封装项(12-15)

byte[0-1]   消息ID word(16)
byte[2-3]   消息体属性 word(16)
        bit[0-9]    消息体长度
        bit[10-12] 数据加密方式
                        此三位都为 0，表示消息体不加密
                        第 10 位为 1，表示消息体经过 RSA 算法加密
                        其它保留
        bit[13]     分包
                        1：消息体卫长消息，进行分包发送处理，具体分包信息由消息包封装项决定
                        0：则消息头中无消息包封装项字段
        bit[14-15] 保留
byte[4-9]   终端手机号或设备ID bcd[6]
        根据安装后终端自身的手机号转换
        手机号不足12 位，则在前面补 0
byte[10-11]     消息流水号 word(16)
        按发送顺序从 0 开始循环累加
byte[12-15]     消息包封装项
        byte[0-1]   消息包总数(word(16))
                        该消息分包后得总包数
        byte[2-3]   包序号(word(16))
                        从 1 开始
        如果消息体属性中相关标识位确定消息分包处理,则该项有内容
        否则无该项

2 解析

整个消息体结构中最复杂的就是消息头了。

2.1 消息体实体类

以下是对整个消息体抽象出来的一个java实体类。

import java.nio.channels.Channel;

public class PackageData {

  /**
   * 16byte 消息头
   */
  protected MsgHeader msgHeader;

  // 消息体字节数组
  protected byte[] msgBodyBytes;

  /**
   * 校验码 1byte
   */
  protected int checkSum;

  //记录每个客户端的channel,以便下发信息给客户端
  protected Channel channel;

  public MsgHeader getMsgHeader() {
    return msgHeader;
  }

  //TODO set 和 get 方法在此处省略

  //消息头
  public static class MsgHeader {
    // 消息ID
    protected int msgId;

    /////// ========消息体属性
    // byte[2-3]
    protected int msgBodyPropsField;
    // 消息体长度
    protected int msgBodyLength;
    // 数据加密方式
    protected int encryptionType;
    // 是否分包,true==>有消息包封装项
    protected boolean hasSubPackage;
    // 保留位[14-15]
    protected String reservedBit;
    /////// ========消息体属性

    // 终端手机号
    protected String terminalPhone;
    // 流水号
    protected int flowId;

    //////// =====消息包封装项
    // byte[12-15]
    protected int packageInfoField;
    // 消息包总数(word(16))
    protected long totalSubPackage;
    // 包序号(word(16))这次发送的这个消息包是分包中的第几个消息包, 从 1 开始
    protected long subPackageSeq;
    //////// =====消息包封装项

    //TODO set 和 get 方法在此处省略
  }

}

2.2 字节数组到消息体实体类的转换

2.2.1 消息转换器

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import cn.hylexus.jt808.util.BCD8421Operater;
import cn.hylexus.jt808.util.BitOperator;
import cn.hylexus.jt808.vo.PackageData;
import cn.hylexus.jt808.vo.PackageData.MsgHeader;

public class MsgDecoder {

  private static final Logger log = LoggerFactory.getLogger(MsgDecoder.class);

  private BitOperator bitOperator;
  private BCD8421Operater bcd8421Operater;

  public MsgDecoder() {
    this.bitOperator = new BitOperator();
    this.bcd8421Operater = new BCD8421Operater();
  }

  //字节数组到消息体实体类
  public PackageData queueElement2PackageData(byte[] data) {
    PackageData ret = new PackageData();

    // 1. 16byte 或 12byte 消息头
    MsgHeader msgHeader = this.parseMsgHeaderFromBytes(data);
    ret.setMsgHeader(msgHeader);

    int msgBodyByteStartIndex = 12;
    // 2. 消息体
    // 有子包信息,消息体起始字节后移四个字节:消息包总数(word(16))+包序号(word(16))
    if (msgHeader.isHasSubPackage()) {
      msgBodyByteStartIndex = 16;
    }

    byte[] tmp = new byte[msgHeader.getMsgBodyLength()];
    System.arraycopy(data, msgBodyByteStartIndex, tmp, 0, tmp.length);
    ret.setMsgBodyBytes(tmp);

    // 3. 去掉分隔符之后，最后一位就是校验码
    // int checkSumInPkg =
    // this.bitOperator.oneByteToInteger(data[data.length - 1]);
    int checkSumInPkg = data[data.length - 1];
    int calculatedCheckSum = this.bitOperator.getCheckSum4JT808(data, 0, data.length - 1);
    ret.setCheckSum(checkSumInPkg);
    if (checkSumInPkg != calculatedCheckSum) {
      log.warn("检验码不一致,msgid:{},pkg:{},calculated:{}", msgHeader.getMsgId(), checkSumInPkg, calculatedCheckSum);
    }
    return ret;
  }

  private MsgHeader parseMsgHeaderFromBytes(byte[] data) {
    MsgHeader msgHeader = new MsgHeader();

    // 1. 消息ID word(16)
    // byte[] tmp = new byte[2];
    // System.arraycopy(data, 0, tmp, 0, 2);
    // msgHeader.setMsgId(this.bitOperator.twoBytesToInteger(tmp));
    msgHeader.setMsgId(this.parseIntFromBytes(data, 0, 2));

    // 2. 消息体属性 word(16)=================>
    // System.arraycopy(data, 2, tmp, 0, 2);
    // int msgBodyProps = this.bitOperator.twoBytesToInteger(tmp);
    int msgBodyProps = this.parseIntFromBytes(data, 2, 2);
    msgHeader.setMsgBodyPropsField(msgBodyProps);
    // [ 0-9 ] 0000,0011,1111,1111(3FF)(消息体长度)
    msgHeader.setMsgBodyLength(msgBodyProps & 0x1ff);
    // [10-12] 0001,1100,0000,0000(1C00)(加密类型)
    msgHeader.setEncryptionType((msgBodyProps & 0xe00) >> 10);
    // [ 13_ ] 0010,0000,0000,0000(2000)(是否有子包)
    msgHeader.setHasSubPackage(((msgBodyProps & 0x2000) >> 13) == 1);
    // [14-15] 1100,0000,0000,0000(C000)(保留位)
    msgHeader.setReservedBit(((msgBodyProps & 0xc000) >> 14) + "");
    // 消息体属性 word(16)<=================

    // 3. 终端手机号 bcd[6]
    // tmp = new byte[6];
    // System.arraycopy(data, 4, tmp, 0, 6);
    // msgHeader.setTerminalPhone(this.bcd8421Operater.bcd2String(tmp));
    msgHeader.setTerminalPhone(this.parseBcdStringFromBytes(data, 4, 6));

    // 4. 消息流水号 word(16) 按发送顺序从 0 开始循环累加
    // tmp = new byte[2];
    // System.arraycopy(data, 10, tmp, 0, 2);
    // msgHeader.setFlowId(this.bitOperator.twoBytesToInteger(tmp));
    msgHeader.setFlowId(this.parseIntFromBytes(data, 10, 2));

    // 5. 消息包封装项
    // 有子包信息
    if (msgHeader.isHasSubPackage()) {
      // 消息包封装项字段
      msgHeader.setPackageInfoField(this.parseIntFromBytes(data, 12, 4));
      // byte[0-1] 消息包总数(word(16))
      // tmp = new byte[2];
      // System.arraycopy(data, 12, tmp, 0, 2);
      // msgHeader.setTotalSubPackage(this.bitOperator.twoBytesToInteger(tmp));
      msgHeader.setTotalSubPackage(this.parseIntFromBytes(data, 12, 2));

      // byte[2-3] 包序号(word(16)) 从 1 开始
      // tmp = new byte[2];
      // System.arraycopy(data, 14, tmp, 0, 2);
      // msgHeader.setSubPackageSeq(this.bitOperator.twoBytesToInteger(tmp));
      msgHeader.setSubPackageSeq(this.parseIntFromBytes(data, 12, 2));
    }
    return msgHeader;
  }

  protected String parseStringFromBytes(byte[] data, int startIndex, int lenth) {
    return this.parseStringFromBytes(data, startIndex, lenth, null);
  }

  private String parseStringFromBytes(byte[] data, int startIndex, int lenth, String defaultVal) {
    try {
      byte[] tmp = new byte[lenth];
      System.arraycopy(data, startIndex, tmp, 0, lenth);
      return new String(tmp, "UTF-8");
    } catch (Exception e) {
      log.error("解析字符串出错:{}", e.getMessage());
      e.printStackTrace();
      return defaultVal;
    }
  }

  private String parseBcdStringFromBytes(byte[] data, int startIndex, int lenth) {
    return this.parseBcdStringFromBytes(data, startIndex, lenth, null);
  }

  private String parseBcdStringFromBytes(byte[] data, int startIndex, int lenth, String defaultVal) {
    try {
      byte[] tmp = new byte[lenth];
      System.arraycopy(data, startIndex, tmp, 0, lenth);
      return this.bcd8421Operater.bcd2String(tmp);
    } catch (Exception e) {
      log.error("解析BCD(8421码)出错:{}", e.getMessage());
      e.printStackTrace();
      return defaultVal;
    }
  }

  private int parseIntFromBytes(byte[] data, int startIndex, int length) {
    return this.parseIntFromBytes(data, startIndex, length, 0);
  }

  private int parseIntFromBytes(byte[] data, int startIndex, int length, int defaultVal) {
    try {
      // 字节数大于4,从起始索引开始向后处理4个字节,其余超出部分丢弃
      final int len = length > 4 ? 4 : length;
      byte[] tmp = new byte[len];
      System.arraycopy(data, startIndex, tmp, 0, len);
      return bitOperator.byteToInteger(tmp);
    } catch (Exception e) {
      log.error("解析整数出错:{}", e.getMessage());
      e.printStackTrace();
      return defaultVal;
    }
  }
}

2.2.2 用到的工具类
2.2.2.1 BCD操作工具类

package cn.hylexus.jt808.util;

public class BCD8421Operater {

  /**
   * BCD字节数组===>String
   * 
   * @param bytes
   * @return 十进制字符串
   */
  public String bcd2String(byte[] bytes) {
    StringBuilder temp = new StringBuilder(bytes.length * 2);
    for (int i = 0; i < bytes.length; i++) {
      // 高四位
      temp.append((bytes[i] & 0xf0) >>> 4);
      // 低四位
      temp.append(bytes[i] & 0x0f);
    }
    return temp.toString().substring(0, 1).equalsIgnoreCase("0") ? temp.toString().substring(1) : temp.toString();
  }

  /**
   * 字符串==>BCD字节数组
   * 
   * @param str
   * @return BCD字节数组
   */
  public byte[] string2Bcd(String str) {
    // 奇数,前补零
    if ((str.length() & 0x1) == 1) {
      str = "0" + str;
    }

    byte ret[] = new byte[str.length() / 2];
    byte bs[] = str.getBytes();
    for (int i = 0; i < ret.length; i++) {

      byte high = ascII2Bcd(bs[2 * i]);
      byte low = ascII2Bcd(bs[2 * i + 1]);

      // TODO 只遮罩BCD低四位?
      ret[i] = (byte) ((high << 4) | low);
    }
    return ret;
  }

  private byte ascII2Bcd(byte asc) {
    if ((asc >= '0') && (asc <= '9'))
      return (byte) (asc - '0');
    else if ((asc >= 'A') && (asc <= 'F'))
      return (byte) (asc - 'A' + 10);
    else if ((asc >= 'a') && (asc <= 'f'))
      return (byte) (asc - 'a' + 10);
    else
      return (byte) (asc - 48);
  }
}

2.2.2.2 位操作工具类

package cn.hylexus.jt808.util;

import java.util.Arrays;
import java.util.List;

public class BitOperator {

  /**
   * 把一个整形该为byte
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public byte integerTo1Byte(int value) {
    return (byte) (value & 0xFF);
  }

  /**
   * 把一个整形该为1位的byte数组
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public byte[] integerTo1Bytes(int value) {
    byte[] result = new byte[1];
    result[0] = (byte) (value & 0xFF);
    return result;
  }

  /**
   * 把一个整形改为2位的byte数组
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public byte[] integerTo2Bytes(int value) {
    byte[] result = new byte[2];
    result[0] = (byte) ((value >>> 8) & 0xFF);
    result[1] = (byte) (value & 0xFF);
    return result;
  }

  /**
   * 把一个整形改为3位的byte数组
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public byte[] integerTo3Bytes(int value) {
    byte[] result = new byte[3];
    result[0] = (byte) ((value >>> 16) & 0xFF);
    result[1] = (byte) ((value >>> 8) & 0xFF);
    result[2] = (byte) (value & 0xFF);
    return result;
  }

  /**
   * 把一个整形改为4位的byte数组
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public byte[] integerTo4Bytes(int value){
    byte[] result = new byte[4];
    result[0] = (byte) ((value >>> 24) & 0xFF);
    result[1] = (byte) ((value >>> 16) & 0xFF);
    result[2] = (byte) ((value >>> 8) & 0xFF);
    result[3] = (byte) (value & 0xFF);
    return result;
  }

  /**
   * 把byte[]转化位整形,通常为指令用
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public int byteToInteger(byte[] value) {
    int result;
    if (value.length == 1) {
      result = oneByteToInteger(value[0]);
    } else if (value.length == 2) {
      result = twoBytesToInteger(value);
    } else if (value.length == 3) {
      result = threeBytesToInteger(value);
    } else if (value.length == 4) {
      result = fourBytesToInteger(value);
    } else {
      result = fourBytesToInteger(value);
    }
    return result;
  }

  /**
   * 把一个byte转化位整形,通常为指令用
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public int oneByteToInteger(byte value) {
    return (int) value & 0xFF;
  }

  /**
   * 把一个2位的数组转化位整形
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public int twoBytesToInteger(byte[] value) {
    // if (value.length < 2) {
    // throw new Exception("Byte array too short!");
    // }
    int temp0 = value[0] & 0xFF;
    int temp1 = value[1] & 0xFF;
    return ((temp0 << 8) + temp1);
  }

  /**
   * 把一个3位的数组转化位整形
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public int threeBytesToInteger(byte[] value) {
    int temp0 = value[0] & 0xFF;
    int temp1 = value[1] & 0xFF;
    int temp2 = value[2] & 0xFF;
    return ((temp0 << 16) + (temp1 << 8) + temp2);
  }

  /**
   * 把一个4位的数组转化位整形,通常为指令用
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public int fourBytesToInteger(byte[] value) {
    // if (value.length < 4) {
    // throw new Exception("Byte array too short!");
    // }
    int temp0 = value[0] & 0xFF;
    int temp1 = value[1] & 0xFF;
    int temp2 = value[2] & 0xFF;
    int temp3 = value[3] & 0xFF;
    return ((temp0 << 24) + (temp1 << 16) + (temp2 << 8) + temp3);
  }

  /**
   * 把一个4位的数组转化位整形
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public long fourBytesToLong(byte[] value) throws Exception {
    // if (value.length < 4) {
    // throw new Exception("Byte array too short!");
    // }
    int temp0 = value[0] & 0xFF;
    int temp1 = value[1] & 0xFF;
    int temp2 = value[2] & 0xFF;
    int temp3 = value[3] & 0xFF;
    return (((long) temp0 << 24) + (temp1 << 16) + (temp2 << 8) + temp3);
  }

  /**
   * 把一个数组转化长整形
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public long bytes2Long(byte[] value) {
    long result = 0;
    int len = value.length;
    int temp;
    for (int i = 0; i < len; i++) {
      temp = (len - 1 - i) * 8;
      if (temp == 0) {
        result += (value[i] & 0x0ff);
      } else {
        result += (value[i] & 0x0ff) << temp;
      }
    }
    return result;
  }

  /**
   * 把一个长整形改为byte数组
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public byte[] longToBytes(long value){
    return longToBytes(value, 8);
  }

  /**
   * 把一个长整形改为byte数组
   * 
   * @param value
   * @return
   * @throws Exception
   */
  public byte[] longToBytes(long value, int len) {
    byte[] result = new byte[len];
    int temp;
    for (int i = 0; i < len; i++) {
      temp = (len - 1 - i) * 8;
      if (temp == 0) {
        result[i] += (value & 0x0ff);
      } else {
        result[i] += (value >>> temp) & 0x0ff;
      }
    }
    return result;
  }

  /**
   * 得到一个消息ID
   * 
   * @return
   * @throws Exception
   */
  public byte[] generateTransactionID() throws Exception {
    byte[] id = new byte[16];
    System.arraycopy(integerTo2Bytes((int) (Math.random() * 65536)), 0, id, 0, 2);
    System.arraycopy(integerTo2Bytes((int) (Math.random() * 65536)), 0, id, 2, 2);
    System.arraycopy(integerTo2Bytes((int) (Math.random() * 65536)), 0, id, 4, 2);
    System.arraycopy(integerTo2Bytes((int) (Math.random() * 65536)), 0, id, 6, 2);
    System.arraycopy(integerTo2Bytes((int) (Math.random() * 65536)), 0, id, 8, 2);
    System.arraycopy(integerTo2Bytes((int) (Math.random() * 65536)), 0, id, 10, 2);
    System.arraycopy(integerTo2Bytes((int) (Math.random() * 65536)), 0, id, 12, 2);
    System.arraycopy(integerTo2Bytes((int) (Math.random() * 65536)), 0, id, 14, 2);
    return id;
  }

  /**
   * 把IP拆分位int数组
   * 
   * @param ip
   * @return
   * @throws Exception
   */
  public int[] getIntIPValue(String ip) throws Exception {
    String[] sip = ip.split("[.]");
    // if (sip.length != 4) {
    // throw new Exception("error IPAddress");
    // }
    int[] intIP = { Integer.parseInt(sip[0]), Integer.parseInt(sip[1]), Integer.parseInt(sip[2]),
        Integer.parseInt(sip[3]) };
    return intIP;
  }

  /**
   * 把byte类型IP地址转化位字符串
   * 
   * @param address
   * @return
   * @throws Exception
   */
  public String getStringIPValue(byte[] address) throws Exception {
    int first = this.oneByteToInteger(address[0]);
    int second = this.oneByteToInteger(address[1]);
    int third = this.oneByteToInteger(address[2]);
    int fourth = this.oneByteToInteger(address[3]);

    return first + "." + second + "." + third + "." + fourth;
  }

  /**
   * 合并字节数组
   * 
   * @param first
   * @param rest
   * @return
   */
  public byte[] concatAll(byte[] first, byte[]... rest) {
    int totalLength = first.length;
    for (byte[] array : rest) {
      if (array != null) {
        totalLength += array.length;
      }
    }
    byte[] result = Arrays.copyOf(first, totalLength);
    int offset = first.length;
    for (byte[] array : rest) {
      if (array != null) {
        System.arraycopy(array, 0, result, offset, array.length);
        offset += array.length;
      }
    }
    return result;
  }

  /**
   * 合并字节数组
   * 
   * @param rest
   * @return
   */
  public byte[] concatAll(List<byte[]> rest) {
    int totalLength = 0;
    for (byte[] array : rest) {
      if (array != null) {
        totalLength += array.length;
      }
    }
    byte[] result = new byte[totalLength];
    int offset = 0;
    for (byte[] array : rest) {
      if (array != null) {
        System.arraycopy(array, 0, result, offset, array.length);
        offset += array.length;
      }
    }
    return result;
  }

  public float byte2Float(byte[] bs) {
    return Float.intBitsToFloat(
        (((bs[3] & 0xFF) << 24) + ((bs[2] & 0xFF) << 16) + ((bs[1] & 0xFF) << 8) + (bs[0] & 0xFF)));
  }

  public float byteBE2Float(byte[] bytes) {
    int l;
    l = bytes[0];
    l &= 0xff;
    l |= ((long) bytes[1] << 8);
    l &= 0xffff;
    l |= ((long) bytes[2] << 16);
    l &= 0xffffff;
    l |= ((long) bytes[3] << 24);
    return Float.intBitsToFloat(l);
  }

  public int getCheckSum4JT808(byte[] bs, int start, int end) {
    if (start < 0 || end > bs.length)
      throw new ArrayIndexOutOfBoundsException("getCheckSum4JT808 error : index out of bounds(start=" + start
          + ",end=" + end + ",bytes length=" + bs.length + ")");
    int cs = 0;
    for (int i = start; i < end; i++) {
      cs ^= bs[i];
    }
    return cs;
  }

  public int getBitRange(int number, int start, int end) {
    if (start < 0)
      throw new IndexOutOfBoundsException("min index is 0,but start = " + start);
    if (end >= Integer.SIZE)
      throw new IndexOutOfBoundsException("max index is " + (Integer.SIZE - 1) + ",but end = " + end);

    return (number << Integer.SIZE - (end + 1)) >>> Integer.SIZE - (end - start + 1);
  }

  public int getBitAt(int number, int index) {
    if (index < 0)
      throw new IndexOutOfBoundsException("min index is 0,but " + index);
    if (index >= Integer.SIZE)
      throw new IndexOutOfBoundsException("max index is " + (Integer.SIZE - 1) + ",but " + index);

    return ((1 << index) & number) >> index;
  }

  public int getBitAtS(int number, int index) {
    String s = Integer.toBinaryString(number);
    return Integer.parseInt(s.charAt(index) + "");
  }

  @Deprecated
  public int getBitRangeS(int number, int start, int end) {
    String s = Integer.toBinaryString(number);
    StringBuilder sb = new StringBuilder(s);
    while (sb.length() < Integer.SIZE) {
      sb.insert(0, "0");
    }
    String tmp = sb.reverse().substring(start, end + 1);
    sb = new StringBuilder(tmp);
    return Integer.parseInt(sb.reverse().toString(), 2);
  }
}

2.3 和netty结合

2.3.1 netty处理器链

import java.util.concurrent.TimeUnit;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import cn.kkbc.tpms.tcp.service.TCPServerHandler;
import io.netty.bootstrap.ServerBootstrap;
import io.netty.buffer.Unpooled;
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;
import io.netty.handler.codec.DelimiterBasedFrameDecoder;
import io.netty.handler.timeout.IdleStateHandler;
import io.netty.util.concurrent.Future;

public class TCPServer2 {

  private Logger log = LoggerFactory.getLogger(getClass());
  private volatile boolean isRunning = false;

  private EventLoopGroup bossGroup = null;
  private EventLoopGroup workerGroup = null;
  private int port;

  public TCPServer2() {
  }

  public TCPServer2(int port) {
    this();
    this.port = port;
  }

  private void bind() throws Exception {
    this.bossGroup = new NioEventLoopGroup();
    this.workerGroup = new NioEventLoopGroup();
    ServerBootstrap serverBootstrap = new ServerBootstrap();
    serverBootstrap.group(bossGroup, workerGroup)//
        .channel(NioServerSocketChannel.class) //
        .childHandler(new ChannelInitializer<SocketChannel>() { //
          @Override
          public void initChannel(SocketChannel ch) throws Exception {
            //超过15分钟未收到客户端消息则自动断开客户端连接
            ch.pipeline().addLast("idleStateHandler",
                new IdleStateHandler(15, 0, 0, TimeUnit.MINUTES));
            //ch.pipeline().addLast(new Decoder4LoggingOnly());
            // 1024表示单条消息的最大长度，解码器在查找分隔符的时候，达到该长度还没找到的话会抛异常
            ch.pipeline().addLast(
                new DelimiterBasedFrameDecoder(1024, Unpooled.copiedBuffer(new byte[] { 0x7e }),
                    Unpooled.copiedBuffer(new byte[] { 0x7e, 0x7e })));
            ch.pipeline().addLast(new TCPServerHandler());
          }
        }).option(ChannelOption.SO_BACKLOG, 128) //
        .childOption(ChannelOption.SO_KEEPALIVE, true);

    this.log.info("TCP服务启动完毕,port={}", this.port);
    ChannelFuture channelFuture = serverBootstrap.bind(port).sync();

    channelFuture.channel().closeFuture().sync();
  }

  public synchronized void startServer() {
    if (this.isRunning) {
      throw new IllegalStateException(this.getName() + " is already started .");
    }
    this.isRunning = true;

    new Thread(() -> {
      try {
        this.bind();
      } catch (Exception e) {
        this.log.info("TCP服务启动出错:{}", e.getMessage());
        e.printStackTrace();
      }
    }, this.getName()).start();
  }

  public synchronized void stopServer() {
    if (!this.isRunning) {
      throw new IllegalStateException(this.getName() + " is not yet started .");
    }
    this.isRunning = false;

    try {
      Future<?> future = this.workerGroup.shutdownGracefully().await();
      if (!future.isSuccess()) {
        log.error("workerGroup 无法正常停止:{}", future.cause());
      }

      future = this.bossGroup.shutdownGracefully().await();
      if (!future.isSuccess()) {
        log.error("bossGroup 无法正常停止:{}", future.cause());
      }
    } catch (InterruptedException e) {
      e.printStackTrace();
    }

    this.log.info("TCP服务已经停止...");
  }

  private String getName() {
    return "TCP-Server";
  }

  public static void main(String[] args) throws Exception {
    TCPServer2 server = new TCPServer2(20048);
    server.startServer();

    // Thread.sleep(3000);
    // server.stopServer();
  }

}

2.3.2 netty针对于JT808的消息处理器

package cn.hylexus.jt808.service;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import cn.hylexus.jt808.server.SessionManager;
import cn.hylexus.jt808.service.codec.MsgDecoder;
import cn.hylexus.jt808.vo.PackageData;
import cn.hylexus.jt808.vo.Session;
import io.netty.buffer.ByteBuf;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInboundHandlerAdapter;
import io.netty.handler.timeout.IdleState;
import io.netty.handler.timeout.IdleStateEvent;
import io.netty.util.ReferenceCountUtil;

public class TCPServerHandler extends ChannelInboundHandlerAdapter { // (1)

  private final Logger logger = LoggerFactory.getLogger(getClass());

  // 一个维护客户端连接的类
  private final SessionManager sessionManager;
  private MsgDecoder decoder = new MsgDecoder();

  public TCPServerHandler() {
    this.sessionManager = SessionManager.getInstance();
  }

  @Override
  public void channelRead(ChannelHandlerContext ctx, Object msg) throws InterruptedException { // (2)
    try {
      ByteBuf buf = (ByteBuf) msg;
      if (buf.readableBytes() <= 0) {
        // ReferenceCountUtil.safeRelease(msg);
        return;
      }

      byte[] bs = new byte[buf.readableBytes()];
      buf.readBytes(bs);

      PackageData jt808Msg = this.decoder.queueElement2PackageData(bs);
      // 处理客户端消息
      this.processClientMsg(jt808Msg);
    } finally {
      release(msg);
    }
  }

  private void processClientMsg(PackageData jt808Msg) {
    // TODO 更加消息ID的不同,分别实现自己的业务逻辑
    if (jt808Msg.getMsgHeader().getMsgId() == 0x900) {
      // TODO ...
    } else if (jt808Msg.getMsgHeader().getMsgId() == 0x9001) {
      // TODO ...
    }
    // else if(){}
    // else if(){}
    // else if(){}
    // else if(){}
    // ...
    else {
      logger.error("位置消息,消息ID={}", jt808Msg.getMsgHeader().getMsgId());
    }
  }

  @Override
  public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) { // (4)
    logger.error("发生异常:{}", cause.getMessage());
    cause.printStackTrace();
  }

  @Override
  public void channelActive(ChannelHandlerContext ctx) throws Exception {
    Session session = Session.buildSession(ctx.channel());
    sessionManager.put(session.getId(), session);
    logger.debug("终端连接:{}", session);
  }

  @Override
  public void channelInactive(ChannelHandlerContext ctx) throws Exception {
    final String sessionId = ctx.channel().id().asLongText();
    Session session = sessionManager.findBySessionId(sessionId);
    this.sessionManager.removeBySessionId(sessionId);
    logger.debug("终端断开连接:{}", session);
    ctx.channel().close();
    // ctx.close();
  }

  @Override
  public void userEventTriggered(ChannelHandlerContext ctx, Object evt) throws Exception {
    if (IdleStateEvent.class.isAssignableFrom(evt.getClass())) {
      IdleStateEvent event = (IdleStateEvent) evt;
      if (event.state() == IdleState.READER_IDLE) {
        Session session = this.sessionManager.removeBySessionId(Session.buildId(ctx.channel()));
        logger.error("服务器主动断开连接:{}", session);
        ctx.close();
      }
    }
  }

  private void release(Object msg) {
    try {
      ReferenceCountUtil.release(msg);
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

2.3.3 用到的其他类

package cn.hylexus.jt808.server;

import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.BiConsumer;
import java.util.stream.Collectors;

import cn.hylexus.jt808.vo.Session;

public class SessionManager {

  private static volatile SessionManager instance = null;
  // netty生成的sessionID和Session的对应关系
  private Map<String, Session> sessionIdMap;
  // 终端手机号和netty生成的sessionID的对应关系
  private Map<String, String> phoneMap;

  public static SessionManager getInstance() {
    if (instance == null) {
      synchronized (SessionManager.class) {
        if (instance == null) {
          instance = new SessionManager();
        }
      }
    }
    return instance;
  }

  public SessionManager() {
    this.sessionIdMap = new ConcurrentHashMap<>();
    this.phoneMap = new ConcurrentHashMap<>();
  }

  public boolean containsKey(String sessionId) {
    return sessionIdMap.containsKey(sessionId);
  }

  public boolean containsSession(Session session) {
    return sessionIdMap.containsValue(session);
  }

  public Session findBySessionId(String id) {
    return sessionIdMap.get(id);
  }

  public Session findByTerminalPhone(String phone) {
    String sessionId = this.phoneMap.get(phone);
    if (sessionId == null)
      return null;
    return this.findBySessionId(sessionId);
  }

  public synchronized Session put(String key, Session value) {
    if (value.getTerminalPhone() != null && !"".equals(value.getTerminalPhone().trim())) {
      this.phoneMap.put(value.getTerminalPhone(), value.getId());
    }
    return sessionIdMap.put(key, value);
  }

  public synchronized Session removeBySessionId(String sessionId) {
    if (sessionId == null)
      return null;
    Session session = sessionIdMap.remove(sessionId);
    if (session == null)
      return null;
    if (session.getTerminalPhone() != null)
      this.phoneMap.remove(session.getTerminalPhone());
    return session;
  }

  public Set<String> keySet() {
    return sessionIdMap.keySet();
  }

  public void forEach(BiConsumer<? super String, ? super Session> action) {
    sessionIdMap.forEach(action);
  }

  public Set<Entry<String, Session>> entrySet() {
    return sessionIdMap.entrySet();
  }

  public List<Session> toList() {
    return this.sessionIdMap.entrySet().stream().map(e -> e.getValue()).collect(Collectors.toList());
  }

}

3 demo级别java示例

请移步: https://github.com/hylexus/jt-808-protocol

另请不要吝啬，在GitHub给个star让小可装装逼…………^_^

注
急急忙忙写的博客，先写个大致的思路,有疑问可以联系本人，联系方式：

emial: hylexus@163.com

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