[Java] 日期与时间的一些操作

import java.text.SimpleDateFormat;
import java.time.*;
import java.time.format.DateTimeFormatter;
import java.util.Date;

// Java时间操作的一些实例 By Titan 2020-04-01
public class TimeStudy {
    public static void main(String[] args) {
        formatDate();
        dateCovert();
    }

    // 格式化当前时间
    public static void formatDate() {
        System.out.println("Format Date");
        // 老API方式
        Date date = new Date();
        String strDateFormat = "yyyy-MM-dd HH:mm:ss";
        SimpleDateFormat sdf = new SimpleDateFormat(strDateFormat);
        System.out.println("The formatted date is : ");
        System.out.println(sdf.format(date));
        // Java8方式
        LocalDateTime lt = LocalDateTime.now();
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        System.out.println("The formatted date is : ");
        System.out.println(formatter.format(lt));
        System.out.println("-------------------------------------------------------");
    }

    // 时间戳与时间日期的互相转换
    public static void dateCovert() {
        LocalDateTime lt = LocalDateTime.now();
        // 获取当前时间戳
        // 秒级时间戳
        long timestamp = lt.toEpochSecond(ZoneOffset.ofHours(8));
        // 毫秒级时间戳
        long milliSecond = LocalDateTime.now().toInstant(ZoneOffset.ofHours(8)).toEpochMilli();
        System.out.println("The current timestamp is: \n" + timestamp);
        System.out.println("The current millisecond timestamp is: \n" + milliSecond);
        // 获取任意时间的时间戳
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
        LocalDateTime newLt = LocalDateTime.parse("2019-01-01 00:00:00", formatter);
        long millSecond2 = newLt.toInstant(ZoneOffset.ofHours(8)).toEpochMilli();
        System.out.println("The mill-second of 2019-01-01 00:00:00 is:\n" + millSecond2);
        // 时间戳转时间
        Instant ins = Instant.ofEpochMilli(millSecond2);
        LocalDateTime localDateTime = LocalDateTime.ofInstant(ins, ZoneOffset.ofHours(8));
        String dateTimeText = localDateTime.format(formatter);
        System.out.println("The LocalDateTime of " + millSecond2 + " is:\n" + dateTimeText);
        System.out.println("-------------------------------------------------------");

    }


}