时区不匹配

Question

我正在使用 Java 的默认 TimeZone 和 Calendar 类来尝试获取不同区域的时间，但是当我尝试使用它时，它没有考虑任何 +0x:00。例如，当我输入“欧洲/英格兰”时，它返回 1:30，而实际上是 2:30，因为现在英格兰使用的是 GMT+1，而不是 GMT。

String timeZone = raw.split(" ")[1];
Calendar calendar = new GregorianCalendar();
TimeZone tz;

try {
    tz = TimeZone.getTimeZone(timeZone);
    calendar.setTimeZone(tz);
} catch (Exception e) {
    event.getChannel().sendMessage("Couldn't find time-zone for: " + timeZone +
        ".\n*Usage: !time <continent/city>*\n*You can find TZ names here: " +
        "https://en.wikipedia.org/wiki/List_of_tz_database_time_zones#List*").queue();
    return;
}

long hours = calendar.get(Calendar.HOUR_OF_DAY);
String minutes = String.valueOf(calendar.get(Calendar.MINUTE));
if (minutes.length() == 1)
    minutes = "0" + minutes;
User author = event.getAuthor();
event.getChannel().sendMessage(author.getAsMention() + " The current time is: **" + hours + ":" + minutes + "** [" + tz.getDisplayName() + "]").queue();

Answer 1

我建议您改用现代的date/time API，而不是使用过时的日期/时间 API。

import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeFormatterBuilder;
import java.time.temporal.ChronoField;

public class Main {
    public static void main(String[] args) {
        ZonedDateTime zdt = ZonedDateTime.now(ZoneId.of("Europe/London"));
        System.out.println(zdt);
        System.out.println(zdt.getHour());
        System.out.println(zdt.getMinute());

        DateTimeFormatter formatter = new DateTimeFormatterBuilder()
                .appendLiteral("Hour: ")
                .appendValue(ChronoField.HOUR_OF_DAY)
                .appendLiteral(", Minute: ")
                .appendValue(ChronoField.MINUTE_OF_HOUR)
                .toFormatter();
        System.out.println(formatter.format(zdt));
    }
}

输出：

2020-06-11T14:54:34.081332+01:00[Europe/London]
14
54
Hour: 14, Minute: 54