esp8266将获取到的网络时间转换为年月日

可以使用C语言中的时间库来实现将网络时间转换为年月日。

以下是一个简单的示例代码，其中包括从服务器获取当前时间和将时间转换为年月日格式的代码：

#include <ESP8266WiFi.h>
#include <WiFiUdp.h>
#include <TimeLib.h>

const char* ssid = "YourSSID";
const char* password = "YourPassword";

WiFiUDP udp;
const char* ntpServerName = "cn.pool.ntp.org";
const int ntpPort = 123;
const int timeZone = 8;

void setup() {
  Serial.begin(115200);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.println("Connecting to WiFi...");
  }
  Serial.println("Connected to WiFi");
  setSyncProvider(getNtpTime);
  setSyncInterval(300);
}

time_t getNtpTime()
{
  IPAddress ntpServerIP;
  while (udp.parsePacket() > 0); 
  WiFi.hostByName(ntpServerName, ntpServerIP);
  sendNTPpacket(ntpServerIP);
  uint32_t beginWait = millis();
  while (millis() - beginWait < 1500) {
    int size = udp.parsePacket();
    if (size >= NTP_PACKET_SIZE) {
      Serial.println("Received NTP Response");
      byte packetBuffer[NTP_PACKET_SIZE];
      udp.read(packetBuffer, NTP_PACKET_SIZE);
      unsigned long secsSince1900;
      secsSince1900 = (unsigned long)packetBuffer[40] << 24;
      secsSince1900 |= (unsigned long)packetBuffer[41] << 16;
      secsSince1900 |= (unsigned long)packetBuffer[42] << 8;
      secsSince1900 |= (unsigned long)packetBuffer[43];
      return secsSince1900 - 2208988800UL + timeZone * SECS_PER_HOUR;  
    }
  }
  Serial.println("No NTP Response :-(");
  return 0; 
}

void sendNTPpacket(IPAddress& address)
{
  byte packetBuffer[NTP_PACKET_SIZE];
  memset(packetBuffer, 0, NTP_PACKET_SIZE);
  packetBuffer[0] = 0b11100011;  
  packetBuffer[1] = 0;    
  packetBuffer[2] = 6;    
  packetBuffer[3] = 0xEC; 
  packetBuffer[12]  = 49; 
  packetBuffer[13]  = 0x4E;
  packetBuffer[14]  = 49;
  packetBuffer[15]  = 52;
  udp.beginPacket(address, ntpPort);
  udp.write(packetBuffer, NTP_PACKET_SIZE);
  udp.endPacket();
}

void loop() {
  if (timeStatus() == timeSet) {
    Serial.print(year());
    Serial.print("-");
    Serial.print(month());
    Serial.print("-");
    Serial.print(day());
    Serial.print(" ");
    Serial.print(hour());
    Serial.print(":");
    Serial.print(minute());
    Serial.print(":");
    Serial.print(second());
    Serial.println(" (UTC)");
  }
  delay(1000);
}

在这个示例代码中，首先连接Wi-Fi，并从NTP服务器获取当前时间。然后使用`year()`，`month()`和`day()`函数将时间转换为年月日格式。请注意，由于ESP8266的时钟速率可能会有所不同，因此需要使用`setSyncInterval()`函数设置同步间隔，以便确保时钟得到精确同步。

希望这可以回答您的问题！