Esp8266 connects to onenet cloud platform (mqtt) through Arduino IDE

const char *Device_ID = "876783185";         // equipment ID
const char *Product_ID = "485561";        // product ID
const char *Api_KEY = "123456";           // Authentication information 
const char *WiFi_SSID = "zongshutao";         //WiFi name 
const char *WiFi_Password = "18853783842"; //WiFi password 
#include <ESP8266WiFi.h>
#include <PubSubClient.h>

#include <SoftwareSerial.h>
SoftwareSerial GpsSerial(D7, D8); //rx,tx
struct
{
    
  char GPS_Buffer[80];
  bool isGetData;   // Whether or not to get GPS data 
  bool isParseData; // Whether the parsing is complete 
  char UTCTime[11];   //UTC Time 
  char latitude[11];    // latitude 
  char N_S[2];    //N/S
  char longitude[12];   // longitude 
  char E_W[2];    //E/W
  bool isUsefull;   // Whether the location information is valid 
  String lat = "";  // latitude 
  String lon = "";  // longitude 

} Save_Data;
const unsigned int gpsRxBufferLength = 600;
char gpsRxBuffer[gpsRxBufferLength];
unsigned int ii = 0;
int L = D4; //LED Indicator pin 
float Current = 0;
uint8_t Upload_Package[200];
uint32_t Last_Updata_Time = 0;
WiFiClient espClient;
PubSubClient client(espClient);

void WiFi_Init(void);            //wifi Connect 
void MQTT_Init(void);            //MQTT initialization 
void MQTT_Reconnection(void);    //MQTT Reconnection function 
void MQTT_Callback(char *MQTT_Topic, uint8_t *MQTT_Payload, uint16_t MQTT_Payload_Len);   //MQTT Callback function 
void setup()
{
    
  Serial.begin(9600);
  WiFi_Init();           //wifi Connect 
  MQTT_Init();           //MQTT initialization 

  GpsSerial.begin(9600);      // Define baud rate 9600, And our shop GPS The baud rate output by the module is consistent 
  Serial.begin(9600);
  Serial.println("Wating...");

  Save_Data.isGetData = false;
  Save_Data.isParseData = false;
  Save_Data.isUsefull = false;
}

void loop()
{
    
  gpsRead();  // obtain GPS data 
  parseGpsBuffer();// analysis GPS data 
  //printGpsBuffer();// Output the parsed data 
  if (!client.connected())    // If you disconnect from the server , Start up QMTT Reconnect the 
    MQTT_Reconnection();
  if (millis() - Last_Updata_Time >= 3000)  // Every time 3 One second scan 
  {
    
    Last_Updata_Time = millis();
    float ADC_Value = random(1000); ;
    Current = (ADC_Value) * 0.033783784;   // Store the calculated floating-point value 
    Serial.print("Current: ");                   // Print the calculated floating-point value 
    Serial.print(Current);
    Serial.println(" A\r\n");
    memset(Upload_Package, 0, 200);              // Copy characters 0 To parameter Upload_Package The front of the string to which it refers 100 Characters . The purpose is to empty Upload_Package Array 
    String Json_Buffer = ",;Current,";
    Json_Buffer += String(Current);
    Json_Buffer += ";";
    Json_Buffer += "GPS,";
    Json_Buffer += "112.023456";
    Json_Buffer += "b";
    Json_Buffer += "36.083456";
    Json_Buffer += "c1";
    Json_Buffer += ";";
    Upload_Package[0] = 5;
    Upload_Package[1] = highByte(Json_Buffer.length());
    Upload_Package[2] = lowByte(Json_Buffer.length());
    for (int i = 0; i < Json_Buffer.length(); i++)
      Upload_Package[i + 3] = Json_Buffer.c_str()[i];
    client.publish("$dp", Upload_Package, Json_Buffer.length() + 3);
  }
  client.loop();
}
void WiFi_Init(void)
{
    
  Serial.print("\r\n\r\n Connecting to ");
  Serial.print(WiFi_SSID);
  WiFi.mode(WIFI_STA);
  WiFi.begin(WiFi_SSID, WiFi_Password);
  while (WiFi.status() != WL_CONNECTED)
  {
    
    delay(500);
    Serial.print(".");
  }
  Serial.print("\r\n Connected WiFi.\r\n IP Address ：");
  Serial.println(WiFi.localIP());
}

void MQTT_Init(void)
{
    
  client.setServer("183.230.40.39", 6002);
  client.setCallback(MQTT_Callback);
}
void MQTT_Callback(char *MQTT_Topic, uint8_t *MQTT_Payload, uint16_t MQTT_Payload_Len)
{
    
  Serial.printf("Topic: %s[%d]:\r\n", MQTT_Topic, MQTT_Payload_Len);
  //Serial.print(MQTT_Payload[i]);
  for (uint16_t i = 0; i < MQTT_Payload_Len; i++)
  {
    
    //Serial.print(MQTT_Payload[i] < 0x10 ? " 0x0" : " 0x");
    Serial.print(MQTT_Payload[i]);
  }
  Serial.println();
}
void MQTT_Reconnection(void)
{
    
  while (!client.connected())
  {
    
    Serial.println("MQTT Reconnection .");
    if (client.connect(Device_ID, Product_ID, Api_KEY))
      Serial.println("MQTT Connected ");
    else
    {
    
      Serial.print(" The connection fails , The error code is =");
      Serial.print(client.state());
      Serial.println(", Please be there. 5 Try again in seconds .");
      delay(5000);
    }
  }
}


void errorLog(int num)
{
    
  Serial.print(" error ");
  Serial.println(num);
  while (1)
  {
    
    digitalWrite(L, HIGH);
    delay(300);
    digitalWrite(L, LOW);
    delay(300);
  }
}

void printGpsBuffer() {
    
  if (Save_Data.isParseData)
  {
    
    Save_Data.isParseData = false;

    Serial.print("Save_Data.UTCTime = ");
    Serial.println(Save_Data.UTCTime);

    if (Save_Data.isUsefull)
    {
    
      Save_Data.isUsefull = false;
      Serial.print("Save_Data.latitude = ");
      Serial.println(Save_Data.lat);
      Serial.print("Save_Data.N_S = ");
      Serial.println(Save_Data.N_S);
      Serial.print("Save_Data.longitude = ");
      Serial.println(Save_Data.lon);
      Serial.print("Save_Data.E_W = ");
      Serial.println(Save_Data.E_W);
    }
    else
    {
    
      Serial.println("GPS Data doesn't work ！");
    }

  }
}

void parseGpsBuffer() {
     // analysis GPS data 
  char *subString;
  char *subStringNext;
  if (Save_Data.isGetData)
  {
    
    Save_Data.isGetData = false;
    Serial.println("**************");
    Serial.println(Save_Data.GPS_Buffer);


    for (int i = 0 ; i <= 6 ; i++)
    {
    
      if (i == 0)
      {
    
        if ((subString = strstr(Save_Data.GPS_Buffer, ",")) == NULL)
          errorLog(1);  // Parse error 
      }
      else
      {
    
        subString++;
        if ((subStringNext = strstr(subString, ",")) != NULL)
        {
    
          char usefullBuffer[2];
          switch (i)
          {
    
            case 1: memcpy(Save_Data.UTCTime, subString, subStringNext - subString); break; // obtain UTC Time 
            case 2: memcpy(usefullBuffer, subString, subStringNext - subString); break; // obtain UTC Time 
            case 3: memcpy(Save_Data.latitude, subString, subStringNext - subString); break; // Get latitude information 
            case 4: memcpy(Save_Data.N_S, subString, subStringNext - subString); break; // obtain N/S
            case 5: memcpy(Save_Data.longitude, subString, subStringNext - subString); break; // Get latitude information 
            case 6: memcpy(Save_Data.E_W, subString, subStringNext - subString); break; // obtain E/W

            default: break;
          }
          Save_Data.lat = Save_Data.latitude;
          Save_Data.lon = Save_Data.longitude;
          tempString(Save_Data.lat);
          tempString(Save_Data.lon);
          subString = subStringNext;
          Save_Data.isParseData = true;
          if (usefullBuffer[0] == 'A')
            Save_Data.isUsefull = true;
          else if (usefullBuffer[0] == 'V')
            Save_Data.isUsefull = false;

        }
        else
        {
    
          errorLog(2);  // Parse error 
        }
      }


    }
  }
}


void gpsRead() {
    
  while (GpsSerial.available())
  {
    
    gpsRxBuffer[ii++] = GpsSerial.read();
    if (ii == gpsRxBufferLength)clrGpsRxBuffer();
  }

  char* GPS_BufferHead;
  char* GPS_BufferTail;
  if ((GPS_BufferHead = strstr(gpsRxBuffer, "$GPRMC,")) != NULL || (GPS_BufferHead = strstr(gpsRxBuffer, "$GNRMC,")) != NULL )
  {
    
    if (((GPS_BufferTail = strstr(GPS_BufferHead, "\r\n")) != NULL) && (GPS_BufferTail > GPS_BufferHead))
    {
    
      memcpy(Save_Data.GPS_Buffer, GPS_BufferHead, GPS_BufferTail - GPS_BufferHead);
      Save_Data.isGetData = true;

      clrGpsRxBuffer();
    }
  }
}

void clrGpsRxBuffer(void)
{
    
  memset(gpsRxBuffer, 0, gpsRxBufferLength);      // Empty 
  ii = 0;
}


void tempString(String &nu) {
    
  for (int i = 0; i < nu.length() - 1; i++) {
    
    if (nu[i] == '.') {
    
      char temp = nu[i - 1];
      nu[i - 1] = nu[i];
      nu[i] = temp;
      temp = nu[i - 2];
      nu[i - 2] = nu[i - 1];
      nu[i - 1] = temp;
      break;
    }
  }
}