Java8 DateTimeFormatter使用

已经9102年了，别再使用simpledateformat了，和SimpleDateFormat不同的是，DateTimeFormatter不但是不变对象，它还是线程安全的。因为SimpleDateFormat不是线程安全的，使用的时候，只能在方法内部创建新的局部变量。而DateTimeFormatter可以只创建一个实例，到处引用。

public class DataTimeUtils {

    public static final DateTimeFormatter TIME_FORMATTER = DateTimeFormatter.ofPattern("HHmmss");
    public static final DateTimeFormatter YEAR_MONTH_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM");
    public static final DateTimeFormatter SHORT_DATE_FORMATTER = DateTimeFormatter.ofPattern("yyMMdd");
    public static final DateTimeFormatter DATE_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    public static final DateTimeFormatter SHORT_DATETIME_FORMATTER = DateTimeFormatter.ofPattern("yyMMddHHmmss");
    public static final DateTimeFormatter DATETIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
    public static final DateTimeFormatter LONG_DATETIME_FORMATTER = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss SSS");

    /**
     * 返回当前的日期
     */
    public static LocalDate getCurrentLocalDate() {
        return LocalDate.now();
    }

    /**
     * 返回当前时间
     */
    public static LocalTime getCurrentLocalTime() {
        return LocalTime.now();
    }

    /**
     * 返回当前日期时间
     */
    public static LocalDateTime getCurrentLocalDateTime() {
        return LocalDateTime.now();
    }

    /**
     * yyyy-MM-dd
     */
    public static String getCurrentDateStr() {
        return LocalDate.now().format(DATE_FORMATTER);
    }

    /**
     * yyMMdd
     */
    public static String getCurrentShortDateStr() {
        return LocalDate.now().format(SHORT_DATE_FORMATTER);
    }

    public static String getCurrentMonthStr() {
        return LocalDate.now().format(YEAR_MONTH_FORMATTER);
    }

    /**
     * yyyy-MM-dd HH:mm:ss
     */
    public static String getCurrentDateTimeStr() {
        return LocalDateTime.now().format(DATETIME_FORMATTER);
    }


    public static String getCurrentLongDateTimeStr(){
        return LocalDateTime.now().format(LONG_DATETIME_FORMATTER);
    }

    /**
     * yyMMddHHmmss
     */
    public static String getCurrentShortDateTimeStr() {
        return LocalDateTime.now().format(SHORT_DATETIME_FORMATTER);
    }

    /**
     * HHmmss
     */
    public static String getCurrentTimeStr() {
        return LocalTime.now().format(TIME_FORMATTER);
    }

    public static String getCurrentDateStr(String pattern) {
        return LocalDate.now().format(DateTimeFormatter.ofPattern(pattern));
    }

    public static String getCurrentDateTimeStr(String pattern) {
        return LocalDateTime.now().format(DateTimeFormatter.ofPattern(pattern));
    }

    public static String getCurrentTimeStr(String pattern) {
        return LocalTime.now().format(DateTimeFormatter.ofPattern(pattern));
    }

    public static LocalDate parseLocalDate(String dateStr, String pattern) {
        return LocalDate.parse(dateStr, DateTimeFormatter.ofPattern(pattern));
    }

    public static LocalDateTime parseLocalDateTime(String dateTimeStr, String pattern) {
        return LocalDateTime.parse(dateTimeStr, DateTimeFormatter.ofPattern(pattern));
    }

    public static LocalTime parseLocalTime(String timeStr, String pattern) {
        return LocalTime.parse(timeStr, DateTimeFormatter.ofPattern(pattern));
    }

    public static String formatLocalDate(LocalDate date, String pattern) {
        return date.format(DateTimeFormatter.ofPattern(pattern));
    }

    public static String formatLocalDateTime(LocalDateTime datetime, String pattern) {
        return datetime.format(DateTimeFormatter.ofPattern(pattern));
    }

    public static String formatLocalTime(LocalTime time, String pattern) {
        return time.format(DateTimeFormatter.ofPattern(pattern));
    }

    public static LocalDate parseLocalDate(String dateStr) {
        return LocalDate.parse(dateStr, DATE_FORMATTER);
    }

    public static LocalDateTime parseLocalDateTime(String dateTimeStr) {
        return LocalDateTime.parse(dateTimeStr, DATETIME_FORMATTER);
    }

    public static LocalDateTime parseLongLocalDateTime(String longDateTimeStr){
        return LocalDateTime.parse(longDateTimeStr, LONG_DATETIME_FORMATTER);
    }

    public static LocalTime parseLocalTime(String timeStr) {
        return LocalTime.parse(timeStr, TIME_FORMATTER);
    }

    public static String formatLocalDate(LocalDate date) {
        return date.format(DATE_FORMATTER);
    }

    public static String formatLocalDateTime(LocalDateTime datetime) {
        return datetime.format(DATETIME_FORMATTER);
    }

    public static String formatLocalTime(LocalTime time) {
        return time.format(TIME_FORMATTER);
    }

    /**
     * 日期相隔秒
     */
    public static long periodHours(LocalDateTime startDateTime, LocalDateTime endDateTime){
        return Duration.between(startDateTime, endDateTime).get(ChronoUnit.SECONDS);
    }

    /**
     * 日期相隔天数
     */
    public static long periodDays(LocalDate startDate, LocalDate endDate) {
        return startDate.until(endDate, ChronoUnit.DAYS);
    }

    /**
     * 日期相隔周数
     */
    public static long periodWeeks(LocalDate startDate, LocalDate endDate) {
        return startDate.until(endDate, ChronoUnit.WEEKS);
    }

    /**
     * 日期相隔月数
     */
    public static long periodMonths(LocalDate startDate, LocalDate endDate) {
        return startDate.until(endDate, ChronoUnit.MONTHS);
    }

    /**
     * 日期相隔年数
     */
    public static long periodYears(LocalDate startDate, LocalDate endDate) {
        return startDate.until(endDate, ChronoUnit.YEARS);
    }

    /**
     * 是否当天
     */
    public static boolean isToday(LocalDate date) {
        return getCurrentLocalDate().equals(date);
    }
    /**
     * 获取当前毫秒数
     */
    public static Long toEpochMilli(LocalDateTime dateTime) {
        return dateTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
    }

    /**
     * 判断是否为闰年
     */
    public static boolean isLeapYear(LocalDate localDate){
        return localDate.isLeapYear();
    }


}