Java解析JT808、H212协议

╰+哭是因爲堅強的太久メ 2024-03-30 17:22 79阅读 0赞

#### Java解析JT808、H212协议 ####

*  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
     *   *  2.2.1 消息转换器
         *  2.2.2 用到的工具类
         *   *  2.2.2.1 BCD操作工具类
             *  2.2.2.2 位操作工具类
     *  2.3 和netty结合
     *   *  2.3.1 netty处理器链
         *  2.3.2 netty针对于JT808的消息处理器
         *  2.3.3 用到的其他类
 *  3.小编存在Gitee仓库里的Demo是保姆级的，希望得到帮助的点个赞留个关注！

## 1 JT808协议扫盲 ##

### 1.1 数据类型 ###

<table> 
 <thead> 
  <tr> 
   <th>数据类型</th> 
   <th>描述及要求</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>BYTE</td> 
   <td>无符号单字节整形（字节， 8 位）</td> 
  </tr> 
  <tr> 
   <td>WORD</td> 
   <td>无符号双字节整形（字， 16 位）</td> 
  </tr> 
  <tr> 
   <td>DWORD</td> 
   <td>无符号四字节整形（双字， 32 位）</td> 
  </tr> 
  <tr> 
   <td>BYTE[n]</td> 
   <td>n 字节</td> 
  </tr> 
  <tr> 
   <td>BCD[n]</td> 
   <td>8421 码， n 字节</td> 
  </tr> 
  <tr> 
   <td>STRING</td> 
   <td>GBK 编码，若无数据，置空</td> 
  </tr> 
 </tbody> 
</table>

### 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.小编存在Gitee仓库里的Demo是保姆级的，希望得到帮助的点个赞留个关注！ ##

[Gitee仓库：][Gitee]https://gitee.com/suihao666/SH-Netty-JT808-HJ212

[Gitee]: https://gitee.com/suihao666/SH-Netty-JT808-HJ212