blocks|key|1094368|text|getTime()返回“自1970年1月1日00:00:00GMT以来的毫秒数”，不多也不少(显然，您必须正确创建它)。你可以随心所欲地格式化它，比如从GregorianCalendar(TimeZone)构造函数开始。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1094369|entityMap^0|0|9|24|R|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

<code>getTime()</code> returns "the number of milliseconds since January 1, 1970, 00:00:00 GMT", nothing more, nothing less (obviously, you have to create it correctly). You can format it however you want, starting with e.g. the <code>GregorianCalendar(TimeZone)</code> constructor.

blocks|key|1309604|text|DateFormat类有a+method+for+setting+your+preferred+time+zone，还有一个时区类有a+setting+for+UTC+time。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1309605|举个例子，|1309606|SimpleDateFormat+sdf+=+new+SimpleDateFormat();
sdf.setTimeZone(new+SimpleTimeZone(SimpleTimeZone.UTC_TIME,+"UTC"));
Date+yourUtcDate+=+sdf.parse(yourOriginalDate);|code-block|syntax|javascript|1309607|entityMap|0|LINK|mutability|MUTABLE|url|http://java.sun.com/javase/6/docs/api/java/text/DateFormat.html#setTimeZone%2528java.util.TimeZone%2529|1|http://java.sun.com/javase/6/docs/api/java/util/SimpleTimeZone.html#UTC_TIME^0|0|A|C|19|0|1U|M|1|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@$9|Z|A|10|1|11]|$9|12|A|13|1|14]]|E|$]]|$1|F|3|G|5|6|7|15|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|16|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]|U|$5|P|Q|R|E|$S|V]]]]

The <code>DateFormat</code> class has <a href="http://java.sun.com/javase/6/docs/api/java/text/DateFormat.html#setTimeZone%28java.util.TimeZone%29" rel="noreferrer">a method for setting your preferred time zone</a>, and there's a time zone class that has <a href="http://java.sun.com/javase/6/docs/api/java/util/SimpleTimeZone.html#UTC_TIME" rel="noreferrer">a setting for UTC time</a>.

So, for example,

<pre><code>SimpleDateFormat sdf = new SimpleDateFormat();
sdf.setTimeZone(new SimpleTimeZone(SimpleTimeZone.UTC_TIME, "UTC"));
Date yourUtcDate = sdf.parse(yourOriginalDate);
</code></pre>

blocks|key|1094454|text|java.util.Date没有时区的概念。它只保存相对于纪元的时间，即Jan+1+1970+00:00:00+UTC。Date是一个模型，独立于视图。显示日期时，将应用时区的概念。date的toString()以默认时区显示人类可读的日期。您可以使用DateFormat显示不同时区的日期，也可以更改其缺省时区。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1094455|entityMap^0|0|E|3I|A|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

<code>java.util.Date</code> has no concept of timezone. It simply holds time relative to epoch, which is Jan 1 1970 00:00:00 UTC. Date is a model, separate from the view. When you display the date, the concept of timezone then is applied. Date's toString() displays a human readable date in the default timezone. You can either use a <code>DateFormat</code> to display a Date in a different timezone (such as UTC), or change the JVM's default timezone.

blocks|key|1094457|text|++++LocalDateTime+now+=+LocalDateTime.now(Clock.systemUTC());
++++Instant+instant+=+now.atZone(ZoneId.systemDefault()).toInstant();
++++Date+formattedDate+=+Date.from(instant);

++++return+formattedDate;|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1094458|unstyled|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|G|8|@]|9|@]|A|$B|C]]|$1|D|3|-4|5|E|7|H|8|@]|9|@]|A|$]]]|F|$]]

<pre><code> LocalDateTime now = LocalDateTime.now(Clock.systemUTC());
 Instant instant = now.atZone(ZoneId.systemDefault()).toInstant();
 Date formattedDate = Date.from(instant);

 return formattedDate;
</code></pre>

blocks|key|1094518|text|大多数Date类函数已被弃用，因为它们现在在Calendar类中进行了移位。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1094519|下面是从Calendar获取UTC时间的代码。|1094520|Date+date+=+new+Date(timeStamp);
Calendar+calendar+=+Calendar.getInstance();
calendar.setTimeZone(TimeZone.getTimeZone("UTC"));
calendar.setTime(date);|code-block|syntax|javascript|1094521|下面是获取年、月等信息的示例代码。|1094522|System.out.println(calendar.get(Calendar.YEAR));
System.out.println(calendar.get(Calendar.MONTH));|1094523|Calendar还支持许多其他有用的信息，如，TIME，DAY_OF_MONTH等。这里的documentation列出了所有这些信息请注意，月份是从0开始的。一月是第0个月。|offset|length|1094524|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.oracle.com/javase/1.5.0/docs/api/java/util/Calendar.html^0|0|0|0|0|0|19|D|0|0^^$0|@$1|2|3|4|5|6|7|Y|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Z|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|11|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|13|8|@]|9|@$O|14|P|15|1|16]]|A|$]]|$1|Q|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|R|$S|$5|T|U|V|A|$W|X]]]]

Most of the Date class functions are deprecated as they are now shifted in Calendar class.

Here is code to get UTC time from Calendar.

<pre><code>Date date = new Date(timeStamp);
Calendar calendar = Calendar.getInstance();
calendar.setTimeZone(TimeZone.getTimeZone("UTC"));
calendar.setTime(date);
</code></pre>

Here is the sample code to get the year, month, etc.

<pre><code>System.out.println(calendar.get(Calendar.YEAR));
System.out.println(calendar.get(Calendar.MONTH));
</code></pre>

Calendar also has support for many other useful information like, TIME, DAY_OF_MONTH, etc. Here the <a href="https://docs.oracle.com/javase/1.5.0/docs/api/java/util/Calendar.html" rel="nofollow noreferrer">documentation</a> listing all of them Please note that the month are 0 based. January is 0th month.

I have a Date object which represents a UTC time. When I use the method getTime() to get the long value of this object, the value returned corresponds to our local time (central US). What is the correct way to get the value back which corresponds to the original UTC time?

Thanks

How to make date.getTime() returns UTC time?

我有一个表示UTC时间的Date对象。当我使用getTime()方法来获取这个对象的长值时，返回的值对应于我们的本地时间(美国中部)。获取与原始UTC时间对应的值的正确方法是什么？谢谢

问如何使date.getTime()返回协调世界时时间？
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