long timestamp; // 從 1970-01-01 00:00:00 UTC 開始的毫秒

在中國時(shí)區(qū) → 顯示 2025-12-25 20:00:00
在紐約時(shí)區(qū) → 顯示 2025-12-25 07:00:00

int year, month, day;

北京是 2025-12-25
紐約也是 2025-12-25
倫敦也是 2025-12-25

Date date = new Date();
System.out.println(date); // 輸出：Wed May 21 15:30:20 CST 2025

LocalDate localDate = LocalDate.now();
System.out.println(localDate); // 輸出：2025-05-21

LocalDate l1 = LocalDate.now();
// 按照時(shí)區(qū)定義日期
LocalDate l2 = LocalDate.now(ZoneId.of("US/Eastern"));

LocalDateTime l3 = LocalDateTime.now();
// 按照時(shí)區(qū)定義日期
LocalDateTime l4 = LocalDateTime.now(ZoneId.of("US/Eastern"));

 public static LocalDate dateToLocalDate(Date date) {
        return date.toInstant()
//                .atZone(ZoneId.systemDefault())
                .atZone(ZoneId.of("US/Eastern"))
                .toLocalDate();
    }
    public static LocalDateTime dateToLocalDateTime(Date date) {
        return date.toInstant()
//                .atZone(ZoneId.systemDefault())
                .atZone(ZoneId.of("US/Eastern"))
                .toLocalDateTime();
    }

public static Date localDateToDate(LocalDate localDate) {
    return Date.from(
              localDate.atStartOfDay(ZoneId.systemDefault()).toInstant()
      );
  }

  public static Date localDateTimeToDate(LocalDateTime localDateTime) {
      return Date.from(
              localDateTime.atZone(ZoneId.systemDefault()).toInstant()
      );
  }

// 日期格式
public static final String DATE_PATTERN = "yyyy-MM-dd";
// 日期時(shí)間格式
public static final String DATETIME_PATTERN = "yyyy-MM-dd HH:mm:ss";
/**
 * LocalDate -> yyyy-MM-dd
 */
public static String formatDate(LocalDate date) {
    if (date == null) {
        return null;
    }
    return date.format(DateTimeFormatter.ofPattern(DATE_PATTERN));
}

/**
 * LocalDateTime -> yyyy-MM-dd HH:mm:ss
 */
public static String formatDateTime(LocalDateTime dateTime) {
    if (dateTime == null) {
        return null;
    }
    return dateTime.format(DateTimeFormatter.ofPattern(DATETIME_PATTERN));
}