Java date time now with milliseconds - yyyy-MM-dd HH:mm:ss.milliseconds or yyyy_MM_dd__HH_mm_ss_milliseconds (java time SSS format)

import java.time.LocalDateTime;

import java.time.format.DateTimeFormatter;

​

public class JavaDateTimeNowExamples {

​

    public static String createDateTimeNowMs() {

        // 2021_05_15__12_29_12_627

        return DateTimeFormatter.ofPattern("yyyy_MM_dd__HH_mm_ss_SSS")

                .format(LocalDateTime.now());

    }

​

    public static String createDateTimeNow() {

        // 2021_05_15__12_29_12

        return DateTimeFormatter.ofPattern("yyyy_MM_dd__HH_mm_ss")

                .format(LocalDateTime.now());

    }

​

    public static void main(String[] args) {

​

        System.out.println(createDateTimeNowMs()); // 2021_05_15__12_29_12_627

        System.out.println(createDateTimeNow());   // 2021_05_15__12_29_12

    }

}

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