问题

I need to parse a time zone from a file in which zones are specified like this: UTC, SAST, etc.

Problem: While ZoneId.of("UTC") works well, I cannot do the same for SAST.

I get java.time.zone.ZoneRulesException: Unknown time-zone ID: SAST.

Question: How to convert "SAST" string to Java's ZoneId?

I know, I can replace "SAST" by "GMT+2" every time I receive it, but it would be great if there was a more elegant way.

答案1

得分: 6

根据Oracle文档，南非标准时间（SAST）是Africa/Johannesburg。
因此，您应该使用：

ZoneId.of("Africa/Johannesburg")

ZoneId.of("Africa/Johannesburg")

答案2

得分: 0

DisplayZoneAndOffSet.java

package com.mkyong;

import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;

public class DisplayZoneAndOffSet {

    public static final boolean SORT_BY_REGION = false;

    public static void main(String[] argv) {

        Map<String, String> sortedMap = new LinkedHashMap<>();

        Map<String, String> allZoneIdsAndItsOffSet = getAllZoneIdsAndItsOffSet();

        // sort map by key
        if (SORT_BY_REGION) {
            allZoneIdsAndItsOffSet.entrySet().stream()
                    .sorted(Map.Entry.comparingByKey())
                    .forEachOrdered(e -> sortedMap.put(e.getKey(), e.getValue()));
        } else {
            // sort by value, descending order
            allZoneIdsAndItsOffSet.entrySet().stream()
                    .sorted(Map.Entry.<String, String>comparingByValue().reversed())
                    .forEachOrdered(e -> sortedMap.put(e.getKey(), e.getValue()));
        }

        // print map
        sortedMap.forEach((k, v) ->
        {
            String out = String.format("%35s (UTC%s) %n", k, v);
            System.out.printf(out);
        });

        System.out.println("\nTotal Zone IDs " + sortedMap.size());

    }

    private static Map<String, String> getAllZoneIdsAndItsOffSet() {

        Map<String, String> result = new HashMap<>();

        LocalDateTime localDateTime = LocalDateTime.now();

        for (String zoneId : ZoneId.getAvailableZoneIds()) {

            ZoneId id = ZoneId.of(zoneId);

            // LocalDateTime -> ZonedDateTime
            ZonedDateTime zonedDateTime = localDateTime.atZone(id);

            // ZonedDateTime -> ZoneOffset
            ZoneOffset zoneOffset = zonedDateTime.getOffset();

            // replace Z to +00:00
            String offset = zoneOffset.getId().replaceAll("Z", "+00:00");

            result.put(id.toString(), offset);

        }

        return result;

    }

}

DisplayZoneAndOffSet.java
package com.mkyong;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;
import java.time.ZonedDateTime;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
public class DisplayZoneAndOffSet {
public static final boolean SORT_BY_REGION = false;
public static void main(String[] argv) {
Map<String, String> sortedMap = new LinkedHashMap<>();
Map<String, String> allZoneIdsAndItsOffSet = getAllZoneIdsAndItsOffSet();
//sort map by key
if (SORT_BY_REGION) {
allZoneIdsAndItsOffSet.entrySet().stream()
.sorted(Map.Entry.comparingByKey())
.forEachOrdered(e -> sortedMap.put(e.getKey(), e.getValue()));
} else {
// sort by value, descending order
allZoneIdsAndItsOffSet.entrySet().stream()
.sorted(Map.Entry.<String, String>comparingByValue().reversed())
.forEachOrdered(e -> sortedMap.put(e.getKey(), e.getValue()));
}
// print map
sortedMap.forEach((k, v) ->
{
String out = String.format("%35s (UTC%s) %n", k, v);
System.out.printf(out);
});
System.out.println("\nTotal Zone IDs " + sortedMap.size());
}
private static Map<String, String> getAllZoneIdsAndItsOffSet() {
Map<String, String> result = new HashMap<>();
LocalDateTime localDateTime = LocalDateTime.now();
for (String zoneId : ZoneId.getAvailableZoneIds()) {
ZoneId id = ZoneId.of(zoneId);
// LocalDateTime -> ZonedDateTime
ZonedDateTime zonedDateTime = localDateTime.atZone(id);
// ZonedDateTime -> ZoneOffset
ZoneOffset zoneOffset = zonedDateTime.getOffset();
//replace Z to +00:00
String offset = zoneOffset.getId().replaceAll("Z", "+00:00");
result.put(id.toString(), offset);
}
return result;
}