Hướng dẫn và ví dụ Java ZoneId

public abstract class ZoneId implements Serializable {
     public abstract String getId();  
     public abstract ZoneRules getRules();
     ...
}

public static ZoneId of(String zoneId)

ZoneId zoneId1 = ZoneId.of("Europe/Paris");  
ZoneId zoneId2 = ZoneId.of("Asia/Ho_Chi_Minh");  

System.out.println(zoneId1.getId()); // Europe/Paris
System.out.println(zoneId2.getId()); // Asia/Ho_Chi_Minh

// Show format of Zoned Date Time
ZonedDateTime zonedDateTime = ZonedDateTime.of(2021, 6, 22, 0, 0, 0, 0, zoneId2);
System.out.println("zonedDateTime: " + zonedDateTime); // 2021-06-22T00:00+07:00[Asia/Ho_Chi_Minh]

package org.o7planning.zoneid.type.ex;

import java.time.ZoneId;
import java.time.ZonedDateTime;

public class ZoneId_nepal_ex1 {

    public static void main(String[] args) {
        ZoneId nepalZoneId = ZoneId.of("Asia/Kathmandu");

        ZonedDateTime zdt1 = ZonedDateTime.of(1985, 12, 30, 0, 0, 0, 0, nepalZoneId);
        System.out.println(zdt1); // 1985-12-30T00:00+05:30[Asia/Kathmandu]

        System.out.println();

        ZonedDateTime zdt2 = ZonedDateTime.of(1986, 1, 1, 0, 0, 0, 0, nepalZoneId);
        System.out.println(zdt2); // 1986-01-01T00:15+05:45[Asia/Kathmandu]
    }
}

ZoneId nepalZoneId = ZoneId.of("Asia/Kathmandu");

ZoneRules rules = nepalZoneId.getRules();

LocalDateTime ldt1 = LocalDateTime.of(1985, 12, 30, 0, 0, 0, 0);
ZoneOffset offset1 = rules.getOffset(ldt1);
System.out.println(offset1); // +05:30

LocalDateTime ldt2 = LocalDateTime.of(1986, 1, 1, 0, 15, 0, 0);
ZoneOffset offset2 = rules.getOffset(ldt2);  
System.out.println(offset2); // +05:45

// Static method of ZoneOffset class.
public static ZoneOffset of(String offsetId)

public static ZoneOffset ofHours(int hours)  
public static ZoneOffset ofHoursMinutes(int hours, int minutes)  
public static ZoneOffset ofHoursMinutesSeconds(int hours, int minutes, int seconds)
public static ZoneOffset ofTotalSeconds(int totalSeconds)

ZoneId zoneId1 = ZoneOffset.of("-06");
ZoneId zoneId2 = ZoneOffset.of("+06:05:20");
ZoneId zoneId3 = ZoneOffset.ofHoursMinutes(9, 45);

System.out.println(zoneId1.getId()); // -06:00
System.out.println(zoneId2.getId()); // +06:05:20
System.out.println(zoneId3.getId()); // +09:45

// Show format of Zoned Date Time:
ZonedDateTime zonedDateTime = ZonedDateTime.of(2021, 6, 22, 0, 0, 0, 0, zoneId2);
System.out.println("zonedDateTime: " + zonedDateTime); // 2021-06-22T00:00+06:05:20

ZoneId zoneId = ZoneOffset.of("+07:05:30");

System.out.println(zoneId.getId()); // +07:05:30

ZoneRules zoneRules = zoneId.getRules();
ZoneOffset zoneOffset = zoneRules.getOffset(Instant.now());
System.out.println("zoneOffset: " + zoneOffset.getId()); // +07:05:30

public static ZoneId ofOffset(String prefix, ZoneOffset offset)

public static ZoneId of(String zoneId)

ZoneId z31 = ZoneId.ofOffset("UTC", ZoneOffset.of("+06"));
ZoneId z32 = ZoneId.ofOffset("GMT", ZoneOffset.of("-06:05:20"));
ZoneId z33 = ZoneId.ofOffset("UT", ZoneOffset.of("+05:20"));

System.out.println(z31.getId()); // UTC+06:00
System.out.println(z32.getId()); // GMT-06:05:20
System.out.println(z33.getId()); // UT+05:20   

// Parser:
ZoneId z31b = ZoneId.of("UTC+06:00");
ZoneId z32b = ZoneId.of("GMT-06:05:20");
ZoneId z33b = ZoneId.of("UT+05:20");

System.out.println(z31b.getId()); // UTC+06:00
System.out.println(z32b.getId()); // GMT-06:05:20
System.out.println(z33b.getId()); // UT+05:20

ZoneId zoneId = ZoneId.ofOffset("GMT", ZoneOffset.of("+09"));
System.out.println(zoneId); // GMT+09:00

ZoneRules zoneRules = zoneId.getRules();
System.out.println("isFixedOffset? " + zoneRules.isFixedOffset()); // true

ZoneOffset zoneOffset = zoneRules.getOffset(Instant.now());
System.out.println("zoneOffset: " + zoneOffset); // +09:00

// Show format of Zoned Date Time.
ZonedDateTime zonedDateTime = ZonedDateTime.of(2021, 6, 22, 0, 0, 0, 0, zoneId);
System.out.println("zonedDateTime: " + zonedDateTime); // 2021-06-22T00:00+09:00[GMT+09:00]

public static ZoneId systemDefault()    
public static ZoneId from(TemporalAccessor temporal)  
public static ZoneId of(String zoneId, Map<String, String> aliasMap)  
public static ZoneId of(String zoneId)  
public static ZoneId ofOffset(String prefix, ZoneOffset offset)

public static Set<String> getAvailableZoneIds()  
public abstract String getId()  
public String getDisplayName(TextStyle style, Locale locale)  
public abstract ZoneRules getRules();
public ZoneId normalized()

public static ZoneId systemDefault()

ZoneId zoneId = ZoneId.systemDefault();

System.out.println(zoneId);

public static ZoneId of(String zoneId)

// ZoneId from region ID
ZoneId zoneId1 = ZoneId.of("Europe/Paris");
System.out.println("zoneId1: " + zoneId1); // Europe/Paris

ZoneId zoneId2 = ZoneId.of("America/Chicago");
System.out.println("zoneId2: " + zoneId2); // America/Chicago

ZoneId zoneId = ZoneId.of("Z"); // return ZoneOffset.UTC
System.out.println("ZoneId.of('Z'): " + zoneId); // Z
System.out.println("ZoneOffset.UTC: " + ZoneOffset.UTC); // Z

boolean same = zoneId == ZoneOffset.UTC;  
System.out.println("ZoneId.of('Z') == ZoneOffset.UTC? " + same); // true

ZoneId zoneId = ZoneId.of("+09:30");
ZoneOffset zoneOffset1 = (ZoneOffset) zoneId;

// Same as:
ZoneOffset zoneOffset2 = ZoneOffset.of("+09:30");

System.out.println("zoneId: " + zoneId); // +09:30
System.out.println("zoneOffset: " + zoneOffset2); // +09:30
System.out.println("zoneOffset1.equals(zoneOffset2)? " + zoneOffset1.equals(zoneOffset2)); // true

ZoneId zoneId = ZoneOffset.UTC;

ZoneId zoneId1 = ZoneId.of("UTC");
ZoneId zoneId2 = ZoneId.of("GMT");
ZoneId zoneId3 = ZoneId.of("UT");

// Print out Zone-ID
System.out.println(zoneId.getId());  // Z
System.out.println(zoneId1.getId()); // UTC
System.out.println(zoneId2.getId()); // GMT
System.out.println(zoneId3.getId()); // UT

ZoneRules rules = zoneId.getRules();
ZoneRules rules1 = zoneId1.getRules();
ZoneRules rules2 = zoneId2.getRules();
ZoneRules rules3 = zoneId3.getRules();

System.out.println(rules);  // ZoneRules[currentStandardOffset=Z]
System.out.println(rules1); // ZoneRules[currentStandardOffset=Z]
System.out.println(rules2); // ZoneRules[currentStandardOffset=Z]
System.out.println(rules3); // ZoneRules[currentStandardOffset=Z]

System.out.println("rules1.equals(rules): " + rules1.equals(rules)); // true
System.out.println("rules2.equals(rules): " + rules2.equals(rules)); // true
System.out.println("rules3.equals(rules): " + rules3.equals(rules)); // true

// UTC
ZoneId zoneId1a = ZoneId.of("UTC+09:30");
ZoneId zoneId1b = ZoneId.ofOffset("UTC", ZoneOffset.of("+09:30"));
ZoneId zoneId1c = ZoneId.ofOffset("UTC", ZoneOffset.ofHoursMinutes(9, 30));
System.out.println(zoneId1a); // UTC+09:30
System.out.println(zoneId1b); // UTC+09:30
System.out.println(zoneId1c); // UTC+09:30

// GMT
ZoneId zoneId2a = ZoneId.of("GMT+05:30:20");
ZoneId zoneId2b = ZoneId.ofOffset("GMT", ZoneOffset.of("+05:30:20"));
ZoneId zoneId2c = ZoneId.ofOffset("GMT", ZoneOffset.ofHoursMinutesSeconds(5, 30, 20));
System.out.println(zoneId2a); // GMT+05:30:20
System.out.println(zoneId2b); // GMT+05:30:20
System.out.println(zoneId2c); // GMT+05:30:20

// UT
ZoneId zoneId3a = ZoneId.of("UT-07");
ZoneId zoneId3b = ZoneId.ofOffset("UT", ZoneOffset.of("-07"));
ZoneId zoneId3c = ZoneId.ofOffset("UT", ZoneOffset.ofHours(-7));
System.out.println(zoneId3a); // UT-07:00
System.out.println(zoneId3b); // UT-07:00
System.out.println(zoneId3c); // UT-07:00

public static ZoneId of(String zoneId, Map<String, String> aliasMap)

package org.o7planning.zoneid.fm;

import java.time.ZoneId;
import java.util.HashMap;
import java.util.Map;

public class ZoneId_of_aliasMap_ex1 {

    public static void main(String[] args) {
        // Alias IDs:
        Map<String, String> aliasMap = new HashMap<>();
        aliasMap.put("hcm", "Asia/Ho_Chi_Minh");
        aliasMap.put("usc", "US/Central");
        aliasMap.put("prs", "Europe/Paris");

        ZoneId frZoneId = ZoneId.of("prs", aliasMap);
        ZoneId vnZoneId = ZoneId.of("hcm", aliasMap);
        ZoneId usZoneId = ZoneId.of("US/Central", aliasMap);
        ZoneId jpZoneId = ZoneId.of("Asia/Tokyo", aliasMap);
        ZoneId os9ZoneId = ZoneId.of("+09", aliasMap);

        System.out.println(frZoneId); // Europe/Paris
        System.out.println(vnZoneId); // Asia/Ho_Chi_Minh
        System.out.println(usZoneId); // US/Central
        System.out.println(jpZoneId); // Asia/Tokyo
        System.out.println(os9ZoneId); // +09:00

        System.out.println(" ------ ");

        // throws ZoneRulesException - Unknown time-zone ID: xx
        ZoneId xxZoneId = ZoneId.of("xx", aliasMap); // throws ZoneRulesException

        System.out.println(xxZoneId);
    }
}

package org.o7planning.zoneid.fm;

import java.time.ZoneId;
import java.util.Map;

public class ZoneId_of_aliasMap_ex2 {

    public static void main(String[] args) {
        // Alias IDs:
        Map<String, String> aliasMap = ZoneId.SHORT_IDS;

        aliasMap.forEach((k, v) -> System.out.println(k + " --> " + v));

        System.out.println(" ------ ");

        ZoneId zoneId1 = ZoneId.of("JST", aliasMap);
        ZoneId zoneId2 = ZoneId.of("VST", aliasMap);  

        System.out.println(zoneId1); // Asia/Tokyo
        System.out.println(zoneId2); // Asia/Ho_Chi_Minh
    }
}

public static ZoneId ofOffset(String prefix, ZoneOffset offset)

ZoneId zoneId1 = ZoneId.ofOffset("UTC", ZoneOffset.ofHours(9));
ZoneId zoneId2 = ZoneId.ofOffset("GMT", ZoneOffset.ofHoursMinutes(9, 30));
ZoneId zoneId3 = ZoneId.ofOffset("UT", ZoneOffset.ofHours(-7));

ZoneId zoneId4 = ZoneId.ofOffset("", ZoneOffset.ofHours(-5)); // Can cast to ZoneOffset

System.out.println(zoneId1); // UTC+09:00
System.out.println(zoneId2); // GMT+09:30
System.out.println(zoneId3); // UT-07:00
System.out.println(zoneId4); // -05:00

public static ZoneId from(TemporalAccessor temporal)

package org.o7planning.zoneid.fm;

import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.temporal.TemporalAccessor;

public class ZoneId_from_ex1 {

    public static void main(String[] args) {
        // Obtains the current date-time from the system clock in the default time-zone.
        TemporalAccessor temporalAccessor = ZonedDateTime.now();
        System.out.println("ZonedDateTime: " + temporalAccessor);

        ZoneId zoneId = ZoneId.from(temporalAccessor);
        System.out.println("zoneId: " + zoneId);
    }
}

public static Set<String> getAvailableZoneIds()

package org.o7planning.zoneid.ex;

import java.time.ZoneId;
import java.util.Set;

public class ZoneId_getAvailableZoneIds_ex1 {

    public static void main(String[] args) {
        Set<String> zoneIds = ZoneId.getAvailableZoneIds();

        for (String zoneId : zoneIds) {
           System.out.println(zoneId);
        }
    }
}

public abstract ZoneRules getRules()

package org.o7planning.zoneid.ex;

import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.zone.ZoneRules;

public class ZoneId_getRules_ex1 {

    public static void main(String[] args) {
        ZoneId zoneId = ZoneId.of("Asia/Ho_Chi_Minh");
        ZoneRules zoneRules = zoneId.getRules();
        
        ZoneOffset zoneOffset1 = zoneRules.getOffset(LocalDateTime.of(1975, 6, 12, 0, 0, 0));
        ZoneOffset zoneOffset2 = zoneRules.getOffset(LocalDateTime.of(1975, 6, 13, 0, 0, 0));
        
        System.out.println("zoneOffset1: " + zoneOffset1); // +08:00
        System.out.println("zoneOffset2: " + zoneOffset2); // +07:00
    }
}

public ZoneId normalized()

package org.o7planning.zoneid.ex;

import java.time.ZoneId;

public class ZoneId_normalized_ex1 {

    public static void main(String[] args) {
        ZoneId zoneId1 = ZoneId.of("US/Central");
        System.out.println("zoneId1: " + zoneId1); // US/Central
        System.out.println("zoneId1.normalized(): " + zoneId1.normalized()); // US/Central

        ZoneId zoneId2 = ZoneId.of("Asia/Tokyo");
        System.out.println("\nzoneId2: " + zoneId2); // Asia/Tokyo
        System.out.println("zoneId2.normalized(): " + zoneId2.normalized()); // Asia/Tokyo

        ZoneId zoneId3 = ZoneId.of("UTC-09:30");
        System.out.println("\nzoneId3: " + zoneId3); // UTC-09:30
        System.out.println("zoneId3.normalized(): " + zoneId3.normalized()); // -09:30
    }
}