Java的.time.ZoneId类在Java中

ZoneId 用于标识用于在 LocalDateTime 和 Instant of time 之间转换的规则。描述偏移量变化的时间和方式的实际规则由 ZoneRules 定义。这个类只是一个 ID，用来获取底层规则。之所以选择给定的方法，是因为政府定义了规则并经常更改，而 ID 是稳定的。

有两种不同类型的 ID：

固定偏移量是从 UTC/格林威治完全解析的偏移量，它对所有本地日期时间使用相同的偏移量
地理区域是一个社区，其中适用一组选定的用于定位 UTC/格林威治偏移量的规则

Declaration of java.time.ZoneId class

public abstract class ZoneId extends Object implements Serializable

编程需要懂一点英语

区域映射覆盖以启用短时区名称。 Java.util.TimeZone 中已弃用短区域 ID。此映射允许仍通过 of(String, Map) 工厂方法使用 ID。此映射包含符合 TZDB 2005r 及更高版本的 ID 映射，其中“EST”、“MST”和“HST”映射到不包含夏令时的 ID。

这映射如下：

EST	05:00
HST	10:00
MST	07:00
ACT	Australia/Darwin
AET	Australia/Sydney
AGT	America/Argentina/Buenos_Aires
ART	Africa/Cairo
AST	America/Anchorage
BET	America/Sao_Paulo
BST	Asia/Dhaka
CAT	Africa/Harare
CNT	America/St_Johns
CST	America/Chicago
CTT	Asia/Shanghai
EAT	Africa/Addis_Ababa
ECT	Europe/Paris
IET	America/Indiana/Indianapolis
IST	Asia/Kolkata
JST	Asia/Tokyo
MIT	Pacific/Apia
NET	Asia/Yerevan
NST	Pacific/Auckland
PLT	Asia/Karachi
PNT	America/Phoenix
PRT	America/Puerto_Rico
PST	America/Los_Angeles
SST	Pacific/Guadalcanal
VST	Asia/Ho_Chi_Minh

注意：地图不可修改。

ZoneId 类的方法：

Methods	Description
equals(Object obj)	This method checks if this time-zone ID is equal to another time-zone ID.
from(TemporalAccessor temporal)	This method obtains an instance of ZoneId from a temporal object.
getAvailableZoneIds()	This method gets the set of available zone IDs.
getDisplayName(TextStyle style, Locale locale)	This method gets the textual representation of the zone, such as ‘British Time’ or ‘+02:00’.
getId()	This method gets the unique time-zone ID.
getRules()	This method gets the time-zone rules for this ID allowing calculations to be performed.
hashCode()	A hash code for this time-zone ID.
normalized()	This method normalizes the time-zone ID, returning a ZoneOffset where possible.
of(String zoneId)	This method obtains an instance of ZoneId from an ID ensuring that the ID is valid and available for use.
of(String zoneId, Map aliasMap)	This method obtains an instance of ZoneId using its ID using a map of aliases to supplement the standard zone IDs.
ofOffset(String prefix, ZoneOffset offset)	This method obtains an instance of ZoneId wrapping an offset.
systemDefault()	This method gets the system default time-zone.
toString()	This method outputs this zone as a String, using the ID.

下面是一些方法的实现示例：

Java

// java.time.ZoneId Class in Java with example
import java.time.*;
public class GFG {
    public static void main(String[] args)
    {
  
        // Setting Zone1
        ZoneId zoneid1 = ZoneId.of("Asia/Kolkata");
        // Setting Zone2
        ZoneId zoneid2 = ZoneId.of("Europe/London");
        LocalTime time1 = LocalTime.now(zoneid1);
        LocalTime time2 = LocalTime.now(zoneid2);
        System.out.println(time1);
        System.out.println(time2);
  
        // Checking if the time of zone1
        // comes before time of second zone
        System.out.println(time1.isBefore(time2));
    }
}

输出

22:34:11.044312
17:04:11.044385
false