Java 8 - how to format LocalDateTime.now() with different formatters

1. Overview

Below we have examples of how to use LocalDateTime.now() with custom date time format patterns.

2. LocalDateTime.now() custom format with DateTimeFormatter.ofPattern

Code example:

import java.time.LocalDateTime;
import java.time.format.DateTimeFormatter;

public class LocalDateTimeCustomFormatterExample {

    public static void main(String[] args) {

        System.out.println("# Example 1 - default formatter");
        // 2019-10-12T16:09:25.274
        System.out.println(LocalDateTime.now());

        System.out.println("# Example 2");
        // 2019:10:12 16:09:25
        System.out.println(DateTimeFormatter.ofPattern("yyyy:MM:dd HH:mm:ss")
                .format(LocalDateTime.now()));

        System.out.println("# Example 3");
        // 2019:10:12 16:09:25:293
        System.out.println(DateTimeFormatter.ofPattern("yyyy:MM:dd HH:mm:ss:SSS")
                .format(LocalDateTime.now()));

        System.out.println("# Example 4");
        // 20191012_160925294
        System.out.println(DateTimeFormatter.ofPattern("yyyyMMdd_HHmmssSSS")
                .format(LocalDateTime.now()));

        System.out.println("# Example 5");
        // 2019_10_12__16_09_25
        System.out.println(DateTimeFormatter.ofPattern("yyyy_MM_dd__HH_mm_ss")
                        .format(LocalDateTime.now()));

        System.out.println("# Example 6");
        // 2019_10_12__16_09_25_294
        System.out.println(DateTimeFormatter.ofPattern("yyyy_MM_dd__HH_mm_ss_SSS")
                .format(LocalDateTime.now()));
    }
}

Output: 

# Example 1 - default formatter
2019-10-12T16:09:25.274
# Example 2
2019:10:12 16:09:25
# Example 3
2019:10:12 16:09:25:293
# Example 4
20191012_160925294
# Example 5
2019_10_12__16_09_25
# Example 6
2019_10_12__16_09_25_294