blocks|key|3267878|text|java.util.Date没有特定的时区，尽管它的值通常被认为是与协调世界时有关的。是什么让你觉得是当地时间？|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3267879|准确地说：java.util.Date中的值是自Unix纪元以来的毫秒数，该纪元发生在协调世界时1970年1月1日午夜。同样的时期也可以在其他时区描述，但传统的描述是以UTC为单位的。由于距离固定纪元已有几毫秒，因此java.util.Date中的值在世界各地的任何特定时刻都是相同的，而与本地时区无关。|3267880|我怀疑问题在于您正在通过使用本地时区的Calendar实例，或者可能使用也使用本地时区的Date.toString()，或者默认情况下也使用本地时区的SimpleDateFormat实例来显示它。|3267881|如果这不是问题所在，请发布一些示例代码。|3267882|不过，我还是建议您使用Joda-Time，它提供了更清晰的应用程序接口。|3267883|entityMap|0|LINK|mutability|MUTABLE|url|http://www.joda.org/joda-time/^0|0|E|0|5|E|30|E|0|18|F|23|G|0|0|B|9|0|0^^$0|@$1|2|3|4|5|6|7|V|8|@$9|W|A|X|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Y|8|@$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|13|8|@$9|14|A|15|B|C]|$9|16|A|17|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|18|8|@]|D|@]|E|$]]|$1|L|3|M|5|6|7|19|8|@]|D|@$9|1A|A|1B|1|1C]]|E|$]]|$1|N|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]]|O|$P|$5|Q|R|S|E|$T|U]]]]

<code>java.util.Date</code> has no specific time zone, although its value is most commonly thought of in relation to UTC. What makes you think it's in local time?

To be precise: the value within a <code>java.util.Date</code> is the number of milliseconds since the Unix epoch, which occurred at midnight January 1st 1970, UTC. The same epoch could also be described in other time zones, but the traditional description is in terms of UTC. As it's a number of milliseconds since a fixed epoch, the value within <code>java.util.Date</code> is the same around the world at any particular instant, regardless of local time zone.

I suspect the problem is that you're displaying it via an instance of Calendar which uses the local timezone, or possibly using <code>Date.toString()</code> which also uses the local timezone, or a <code>SimpleDateFormat</code> instance, which, by default, also uses local timezone.

If this isn't the problem, please post some sample code.

I would, however, recommend that you use <a href="http://www.joda.org/joda-time/" rel="noreferrer">Joda-Time</a> anyway, which offers a much clearer API.

blocks|key|891626|text|通过以下方式：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|891627|Calendar+cal+=+Calendar.getInstance();|code-block|syntax|javascript|891628|然后cal就有了当前的日期和时间。|offset|length|style|CODE|891629|您还可以使用以下命令获取时区的当前日期和时间：|891630|Calendar+cal2+=+Calendar.getInstance(TimeZone.getTimeZone("GMT-2"));|891631|您可以向cal.get(Calendar.DATE);或其他日历常量询问其他详细信息。|891632|日期和时间戳在Java中已弃用。Calendar类不是。|891633|entityMap^0|0|0|2|3|0|0|0|4|N|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@$I|Z|J|10|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|12|8|@]|9|@]|A|$E|F]]|$1|Q|3|R|5|6|7|13|8|@$I|14|J|15|K|L]]|9|@]|A|$]]|$1|S|3|T|5|6|7|16|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|V|$]]

With:

<pre><code>Calendar cal = Calendar.getInstance();
</code></pre>

Then <code>cal</code> have the current date and time. 
You also could get the current Date and Time for timezone with:

<pre><code>Calendar cal2 = Calendar.getInstance(TimeZone.getTimeZone("GMT-2"));
</code></pre>

You could ask <code>cal.get(Calendar.DATE);</code> or other Calendar constant about others details. 
Date and Timestamp are deprecated in Java. Calendar class it isn't.

blocks|key|46664|text|您可以使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|46665|Calendar+aGMTCalendar+=+Calendar.getInstance(TimeZone.getTimeZone("GMT"));|code-block|syntax|javascript|46666|然后，使用aGMTCalendar对象执行的所有操作都将使用格林尼治标准时间时区完成，并且不会应用夏令时或固定偏移量。我认为前面的帖子是正确的，Date()对象总是返回GMT，直到你对date对象做一些事情，它才会被转换为当地时区。|46667|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

You can use:

<pre><code>Calendar aGMTCalendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
</code></pre>

Then all operations performed using the aGMTCalendar object will be done with the GMT time zone and will not have the daylight savings time or fixed offsets applied. I think the previous poster is correct that the Date() object always returns a GMT it's not until you go to do something with the date object that it gets converted to the local time zone.

blocks|key|3267974|text|++++Calendar+c+=+Calendar.getInstance();
++++System.out.println("current:+"%2Bc.getTime());

++++TimeZone+z+=+c.getTimeZone();
++++int+offset+=+z.getRawOffset();
++++if(z.inDaylightTime(new+Date())){
++++++++offset+=+offset+%2B+z.getDSTSavings();
++++}
++++int+offsetHrs+=+offset+/+1000+/+60+/+60;
++++int+offsetMins+=+offset+/+1000+/+60+%25+60;

++++System.out.println("offset:+"+%2B+offsetHrs);
++++System.out.println("offset:+"+%2B+offsetMins);

++++c.add(Calendar.HOUR_OF_DAY,+(-offsetHrs));
++++c.add(Calendar.MINUTE,+(-offsetMins));

++++System.out.println("GMT+Time:+"%2Bc.getTime());|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3267975|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> Calendar c = Calendar.getInstance();
 System.out.println("current: "+c.getTime());

 TimeZone z = c.getTimeZone();
 int offset = z.getRawOffset();
 if(z.inDaylightTime(new Date())){
 offset = offset + z.getDSTSavings();
 }
 int offsetHrs = offset / 1000 / 60 / 60;
 int offsetMins = offset / 1000 / 60 % 60;

 System.out.println("offset: " + offsetHrs);
 System.out.println("offset: " + offsetMins);

 c.add(Calendar.HOUR_OF_DAY, (-offsetHrs));
 c.add(Calendar.MINUTE, (-offsetMins));

 System.out.println("GMT Time: "+c.getTime());
</code></pre>

blocks|key|3267992|text|SimpleDateFormat+dateFormatGmt+=+new+SimpleDateFormat("yyyy-MMM-dd+HH:mm:ss");
dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));

//Local+time+zone+++
SimpleDateFormat+dateFormatLocal+=+new+SimpleDateFormat("yyyy-MMM-dd+HH:mm:ss");

//Time+in+GMT
return+dateFormatLocal.parse(+dateFormatGmt.format(new+Date())+);|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3267993|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>SimpleDateFormat dateFormatGmt = new SimpleDateFormat("yyyy-MMM-dd HH:mm:ss");
dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));

//Local time zone 
SimpleDateFormat dateFormatLocal = new SimpleDateFormat("yyyy-MMM-dd HH:mm:ss");

//Time in GMT
return dateFormatLocal.parse( dateFormatGmt.format(new Date()) );
</code></pre>

blocks|key|891680|text|aGMTCalendar+=+Calendar.getInstance(TimeZone.getTimeZone("GMT"))；，则使用aGMTCalendar对象执行的所有操作都将使用|type|unstyled|depth|inlineStyleRanges|entityRanges|data|891681|时区完成，并且不会应用夏令时或固定偏移量|blockquote|891682|891683|891684|不对!|891685|Calendar+aGMTCalendar+=+Calendar.getInstance(TimeZone.getTimeZone("GMT"));
aGMTCalendar.getTime();+//or+getTimeInMillis()|code-block|syntax|javascript|891686|和|891687|Calendar+aNotGMTCalendar+=+Calendar.getInstance(TimeZone.getTimeZone("GMT-2"));aNotGMTCalendar.getTime();|891688|会在同一时间返回。标识用于|891689|new+Date();+//it's+not+GMT.|891690|entityMap^0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|X|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|Y|8|@]|9|@]|A|$]]|$1|E|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|10|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|11|8|@]|9|@]|A|$]]|$1|I|3|J|5|K|7|12|8|@]|9|@]|A|$L|M]]|$1|N|3|O|5|6|7|13|8|@]|9|@]|A|$]]|$1|P|3|Q|5|K|7|14|8|@]|9|@]|A|$L|M]]|$1|R|3|S|5|6|7|15|8|@]|9|@]|A|$]]|$1|T|3|U|5|K|7|16|8|@]|9|@]|A|$L|M]]|$1|V|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|W|$]]

<blockquote>
 Calendar aGMTCalendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
 Then all operations performed using the aGMTCalendar object will be done with the GMT time zone and will not have the daylight savings time or fixed offsets applied
</blockquote>

Wrong!

<pre><code>Calendar aGMTCalendar = Calendar.getInstance(TimeZone.getTimeZone("GMT"));
aGMTCalendar.getTime(); //or getTimeInMillis()
</code></pre>

and 

<pre><code>Calendar aNotGMTCalendar = Calendar.getInstance(TimeZone.getTimeZone("GMT-2"));aNotGMTCalendar.getTime();
</code></pre>

will return the same time. Idem for 

<pre><code>new Date(); //it's not GMT.
</code></pre>

blocks|key|891719|text|实际上不是时间，但它的表示可以改变。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|891720|SimpleDateFormat+f+=+new+SimpleDateFormat("yyyy-MMM-dd+HH:mm:ss");
f.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println(f.format(new+Date()));|code-block|syntax|javascript|891721|时间在地球上的任何一点都是一样的，但我们对时间的感知可能会因地点而异。|891722|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Actually not time, but it's representation could be changed.

<pre><code>SimpleDateFormat f = new SimpleDateFormat("yyyy-MMM-dd HH:mm:ss");
f.setTimeZone(TimeZone.getTimeZone("UTC"));
System.out.println(f.format(new Date()));
</code></pre>

Time is the same in any point of the Earth, but our perception of time could be different depending on location.

blocks|key|886534|text|SimpleDateFormat+dateFormatGmt+=+new+SimpleDateFormat("yyyy-MM-dd");
dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));
System.out.println(dateFormatGmt.format(date));|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|886535|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>SimpleDateFormat dateFormatGmt = new SimpleDateFormat("yyyy-MM-dd");
dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));
System.out.println(dateFormatGmt.format(date));
</code></pre>

blocks|key|46839|text|这肯定会返回UTC+time:作为String和Date对象！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|46840|static+final+String+DATE_FORMAT+=+"yyyy-MM-dd+HH:mm:ss";

public+static+Date+getUTCdatetimeAsDate()+{
++++//+note:+doesn't+check+for+null
++++return+stringDateToDate(getUTCdatetimeAsString());
}

public+static+String+getUTCdatetimeAsString()+{
++++final+SimpleDateFormat+sdf+=+new+SimpleDateFormat(DATE_FORMAT);
++++sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
++++final+String+utcTime+=+sdf.format(new+Date());

++++return+utcTime;
}

public+static+Date+stringDateToDate(String+StrDate)+{
++++Date+dateToReturn+=+null;
++++SimpleDateFormat+dateFormat+=+new+SimpleDateFormat(DATEFORMAT);

++++try+{
++++++++dateToReturn+=+(Date)dateFormat.parse(StrDate);
++++}
++++catch+(ParseException+e)+{
++++++++e.printStackTrace();
++++}

++++return+dateToReturn;
}|code-block|syntax|javascript|46841|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This definitely returns UTC time: as String and Date objects !

<pre><code>static final String DATE_FORMAT = "yyyy-MM-dd HH:mm:ss";

public static Date getUTCdatetimeAsDate() {
 // note: doesn't check for null
 return stringDateToDate(getUTCdatetimeAsString());
}

public static String getUTCdatetimeAsString() {
 final SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT);
 sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
 final String utcTime = sdf.format(new Date());

 return utcTime;
}

public static Date stringDateToDate(String StrDate) {
 Date dateToReturn = null;
 SimpleDateFormat dateFormat = new SimpleDateFormat(DATEFORMAT);

 try {
 dateToReturn = (Date)dateFormat.parse(StrDate);
 }
 catch (ParseException e) {
 e.printStackTrace();
 }

 return dateToReturn;
}
</code></pre>

blocks|key|3268137|text|以特定时区和特定格式呈现系统时间的示例代码。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3268138|import+java.text.SimpleDateFormat;
import+java.util.Calendar;
import+java.util.Date;
import+java.util.TimeZone;

public+class+TimZoneTest+{
++++public+static+void+main+(String[]+args){
++++++++//<GMT><%2B/-><hour>:<minutes>
++++++++//+Any+screw+up+in+this+format,+timezone+defaults+to+GMT+QUIETLY.+So+test+your+format+a+few+times.

++++++++System.out.println(my_time_in("GMT-5:00",+"MM/dd/yyyy+HH:mm:ss")+);
++++++++System.out.println(my_time_in("GMT%2B5:30",+"'at'+HH:mm+a+z+'on'+MM/dd/yyyy"));

++++++++System.out.println("---------------------------------------------");
++++++++//+Alternate+format+
++++++++System.out.println(my_time_in("America/Los_Angeles",+"'at'+HH:mm+a+z+'on'+MM/dd/yyyy")+);
++++++++System.out.println(my_time_in("America/Buenos_Aires",+"'at'+HH:mm+a+z+'on'+MM/dd/yyyy")+);


++++}

++++public+static+String+my_time_in(String+target_time_zone,+String+format){
++++++++TimeZone+tz+=+TimeZone.getTimeZone(target_time_zone);
++++++++Date+date+=+Calendar.getInstance().getTime();
++++++++SimpleDateFormat+date_format_gmt+=+new+SimpleDateFormat(format);
++++++++date_format_gmt.setTimeZone(tz);
++++++++return+date_format_gmt.format(date);
++++}

}|code-block|syntax|javascript|3268139|输出|3268140|10/08/2011+21:07:21
at+07:37+AM+GMT%2B05:30+on+10/09/2011
at+19:07+PM+PDT+on+10/08/2011
at+23:07+PM+ART+on+10/08/2011|3268141|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Sample code to render system time in a specific time zone and a specific format.

<pre><code>import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

public class TimZoneTest {
 public static void main (String[] args){
 //&lt;GMT&gt;&lt;+/-&gt;&lt;hour&gt;:&lt;minutes&gt;
 // Any screw up in this format, timezone defaults to GMT QUIETLY. So test your format a few times.

 System.out.println(my_time_in("GMT-5:00", "MM/dd/yyyy HH:mm:ss") );
 System.out.println(my_time_in("GMT+5:30", "'at' HH:mm a z 'on' MM/dd/yyyy"));

 System.out.println("---------------------------------------------");
 // Alternate format 
 System.out.println(my_time_in("America/Los_Angeles", "'at' HH:mm a z 'on' MM/dd/yyyy") );
 System.out.println(my_time_in("America/Buenos_Aires", "'at' HH:mm a z 'on' MM/dd/yyyy") );


 }

 public static String my_time_in(String target_time_zone, String format){
 TimeZone tz = TimeZone.getTimeZone(target_time_zone);
 Date date = Calendar.getInstance().getTime();
 SimpleDateFormat date_format_gmt = new SimpleDateFormat(format);
 date_format_gmt.setTimeZone(tz);
 return date_format_gmt.format(date);
 }

}
</code></pre>

Output

<pre><code>10/08/2011 21:07:21
at 07:37 AM GMT+05:30 on 10/09/2011
at 19:07 PM PDT on 10/08/2011
at 23:07 PM ART on 10/08/2011
</code></pre>

blocks|key|4113629|text|你可以直接使用这个|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4113630|SimpleDateFormat+dateFormatGmt+=+new+SimpleDateFormat("dd:MM:yyyy+HH:mm:ss");
dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));
System.out.println(dateFormatGmt.format(new+Date())%2B"");|code-block|syntax|javascript|4113631|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You can directly use this

<pre><code>SimpleDateFormat dateFormatGmt = new SimpleDateFormat("dd:MM:yyyy HH:mm:ss");
dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));
System.out.println(dateFormatGmt.format(new Date())+"");
</code></pre>

blocks|key|46928|text|如果您希望日期对象的字段针对协调世界时进行了调整，则可以使用Joda+Time执行以下操作|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|46929|import+org.joda.time.DateTimeZone;
import+java.util.Date;

...

Date+local+=+new+Date();
System.out.println("Local:+"+%2B+local);
DateTimeZone+zone+=+DateTimeZone.getDefault();
long+utc+=+zone.convertLocalToUTC(local.getTime(),+false);
System.out.println("UTC:+"+%2B+new+Date(utc));|code-block|syntax|javascript|46930|entityMap|0|LINK|mutability|MUTABLE|url|http://joda-time.sourceforge.net/^0|U|9|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

If you want a Date object with fields adjusted for UTC you can do it like this with <a href="http://joda-time.sourceforge.net/">Joda Time</a>:

<pre><code>import org.joda.time.DateTimeZone;
import java.util.Date;

...

Date local = new Date();
System.out.println("Local: " + local);
DateTimeZone zone = DateTimeZone.getDefault();
long utc = zone.convertLocalToUTC(local.getTime(), false);
System.out.println("UTC: " + new Date(utc));
</code></pre>

blocks|key|4113667|text|下面是获取GMT时间戳对象的另一个建议：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4113668|import+java.sql.Timestamp;
import+java.util.Calendar;

...

private+static+Timestamp+getGMT()+{
+++Calendar+cal+=+Calendar.getInstance();
+++return+new+Timestamp(cal.getTimeInMillis()
+++++++++++++++++++++++-cal.get(Calendar.ZONE_OFFSET)
+++++++++++++++++++++++-cal.get(Calendar.DST_OFFSET));
}|code-block|syntax|javascript|4113669|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here an other suggestion to get a GMT Timestamp object:

<pre><code>import java.sql.Timestamp;
import java.util.Calendar;

...

private static Timestamp getGMT() {
 Calendar cal = Calendar.getInstance();
 return new Timestamp(cal.getTimeInMillis()
 -cal.get(Calendar.ZONE_OFFSET)
 -cal.get(Calendar.DST_OFFSET));
}
</code></pre>

blocks|key|46993|text|为了简单起见，您可以使用Calendar在UTC中创建一个Date：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|46994|Calendar.getInstance(TimeZone.getTimeZone("UTC"));|code-block|syntax|javascript|46995|它将使用"UTC“TimeZone为Calendar构造一个新实例。|46996|如果需要日历中Date对象，只需使用getTime()即可。|46997|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Calendar.html^0|C|8|L|3|T|4|C|8|0|0|0|9|8|I|8|0|7|4|I|9|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]|$9|11|A|12|B|C]]|D|@$9|13|A|14|1|15]]|E|$]]|$1|F|3|G|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|17|8|@$9|18|A|19|B|C]|$9|1A|A|1B|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|1C|8|@$9|1D|A|1E|B|C]|$9|1F|A|1G|B|C]]|D|@]|E|$]]|$1|O|3|-4|5|6|7|1H|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

Just to make this simpler, to create a <code>Date</code> in <code>UTC</code> you can use <a href="http://docs.oracle.com/javase/1.5.0/docs/api/java/util/Calendar.html" rel="nofollow"><code>Calendar</code></a> :

<pre><code>Calendar.getInstance(TimeZone.getTimeZone("UTC"));
</code></pre>

Which will construct a new instance for <code>Calendar</code> using the "UTC" <code>TimeZone</code>.

If you need a <code>Date</code> object from that calendar you could just use <code>getTime()</code>.

blocks|key|886664|text|以下是在Jon+Skeet's+answer中似乎不正确的内容。他说：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|886665|886666|+java.util.Date始终使用协调世界时。是什么让你觉得是当地时间？我怀疑问题是您正在通过使用本地时区的Calendar实例显示它，或者可能使用也使用本地时区的Date.toString()。|blockquote|style|CODE|886667|886668|886669|但是，代码：|886670|System.out.println(new+java.util.Date().getHours()+%2B+"+hours");|code-block|syntax|javascript|886671|给出本地时间，而不是格林尼治标准时间(协调世界时)，不使用Calendar和根本不使用SimpleDateFormat。|886672|这就是为什么有些东西看起来是不正确的。|886673|将响应和代码放在一起：|886674|System.out.println(Calendar.getInstance(TimeZone.getTimeZone("GMT"))
+++++++++++++++++++++++++++.get(Calendar.HOUR_OF_DAY)+%2B+"+Hours");|886675|显示格林尼治标准时间小时数而不是本地小时数--请注意，缺少getTime.getHours()是因为这将创建一个Date()对象，该对象理论上以格林尼治标准时间存储日期，但返回本地时区的小时数。|886676|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/308689/366904^0|4|I|0|0|0|1|E|2C|F|0|0|0|0|0|T|8|17|G|0|0|0|0|T|I|1K|6|0^^$0|@$1|2|3|4|5|6|7|1A|8|@]|9|@$A|1B|B|1C|1|1D]]|C|$]]|$1|D|3|-4|5|6|7|1E|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|1F|8|@$A|1G|B|1H|H|I]|$A|1I|B|1J|H|I]]|9|@]|C|$]]|$1|J|3|-4|5|6|7|1K|8|@]|9|@]|C|$]]|$1|K|3|-4|5|6|7|1L|8|@]|9|@]|C|$]]|$1|L|3|M|5|6|7|1M|8|@]|9|@]|C|$]]|$1|N|3|O|5|P|7|1N|8|@]|9|@]|C|$Q|R]]|$1|S|3|T|5|6|7|1O|8|@$A|1P|B|1Q|H|I]|$A|1R|B|1S|H|I]]|9|@]|C|$]]|$1|U|3|V|5|6|7|1T|8|@]|9|@]|C|$]]|$1|W|3|X|5|6|7|1U|8|@]|9|@]|C|$]]|$1|Y|3|Z|5|P|7|1V|8|@]|9|@]|C|$Q|R]]|$1|10|3|11|5|6|7|1W|8|@$A|1X|B|1Y|H|I]|$A|1Z|B|20|H|I]]|9|@]|C|$]]|$1|12|3|-4|5|6|7|21|8|@]|9|@]|C|$]]]|13|$14|$5|15|16|17|C|$18|19]]]]

Here is what seems to be incorrect in <a href="https://stackoverflow.com/a/308689/366904">Jon Skeet's answer</a>. He said:

<blockquote>
 <code>java.util.Date</code> is always in UTC. What makes you think it's in local
 time? I suspect the problem is that you're displaying it via an
 instance of Calendar which uses the local timezone, or possibly using
 <code>Date.toString()</code> which also uses the local timezone.
</blockquote>

However, the code:

<pre><code>System.out.println(new java.util.Date().getHours() + " hours");
</code></pre>

gives the local hours, not GMT (UTC hours), using no <code>Calendar</code> and no <code>SimpleDateFormat</code> at all.

That is why is seems something is incorrect.

Putting together the responses, the code: 

<pre><code>System.out.println(Calendar.getInstance(TimeZone.getTimeZone("GMT"))
 .get(Calendar.HOUR_OF_DAY) + " Hours");
</code></pre>

shows the GMT hours instead of the local hours -- note that <code>getTime.getHours()</code> is missing because that would create a <code>Date()</code> object, which theoretically stores the date in GMT, but gives back the hours in the local time zone.

blocks|key|4113761|text|以下是以字符串格式获取GMT时间的另一种方法|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4113762|String+DATE_FORMAT+=+"EEE,+dd+MMM+yyyy+HH:mm:ss+z"+;
final+SimpleDateFormat+sdf+=+new+SimpleDateFormat(DATE_FORMAT);
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
String+dateTimeString+=++sdf.format(new+Date());|code-block|syntax|javascript|4113763|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Here is another way to get GMT time in String format

<pre><code>String DATE_FORMAT = "EEE, dd MMM yyyy HH:mm:ss z" ;
final SimpleDateFormat sdf = new SimpleDateFormat(DATE_FORMAT);
sdf.setTimeZone(TimeZone.getTimeZone("GMT"));
String dateTimeString = sdf.format(new Date());
</code></pre>

blocks|key|891832|text|简单地说。calendar对象存储有关时区的信息，但是当您执行cal.getTime()时，时区信息将会丢失。所以对于时区转换，我会建议使用DateFormat类…|type|unstyled|depth|inlineStyleRanges|entityRanges|data|891833|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

To put it simple. A calendar object stores information about time zone but when you perform cal.getTime() then the timezone information will be lost. So for Timezone conversions I will advice to use DateFormat classes...

blocks|key|47112|text|这对我很有效，以GMT返回时间戳！|type|unstyled|depth|inlineStyleRanges|entityRanges|data|47113|++++Date+currDate;
++++SimpleDateFormat+dateFormatGmt+=+new+SimpleDateFormat("yyyy-MMM-dd+HH:mm:ss");
++++dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));
++++SimpleDateFormat+dateFormatLocal+=+new+SimpleDateFormat("yyyy-MMM-dd+HH:mm:ss");

++++long+currTime+=+0;
++++try+{

++++++++currDate+=+dateFormatLocal.parse(+dateFormatGmt.format(new+Date())+);
++++++++currTime+=+currDate.getTime();
++++}+catch+(ParseException+e)+{
++++++++//+TODO+Auto-generated+catch+block
++++++++e.printStackTrace();
++++}|code-block|syntax|javascript|47114|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This worked for me, returns the timestamp in GMT!

<pre><code> Date currDate;
 SimpleDateFormat dateFormatGmt = new SimpleDateFormat("yyyy-MMM-dd HH:mm:ss");
 dateFormatGmt.setTimeZone(TimeZone.getTimeZone("GMT"));
 SimpleDateFormat dateFormatLocal = new SimpleDateFormat("yyyy-MMM-dd HH:mm:ss");

 long currTime = 0;
 try {

 currDate = dateFormatLocal.parse( dateFormatGmt.format(new Date()) );
 currTime = currDate.getTime();
 } catch (ParseException e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }
</code></pre>

blocks|key|891883|text|这适用于在Android中获取UTC毫秒。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|891884|Calendar+c+=+Calendar.getInstance();
int+utcOffset+=+c.get(Calendar.ZONE_OFFSET)+%2B+c.get(Calendar.DST_OFFSET);++
Long+utcMilliseconds+=+c.getTimeInMillis()+%2B+utcOffset;|code-block|syntax|javascript|891885|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This works for getting UTC milliseconds in Android.

<pre><code>Calendar c = Calendar.getInstance();
int utcOffset = c.get(Calendar.ZONE_OFFSET) + c.get(Calendar.DST_OFFSET); 
Long utcMilliseconds = c.getTimeInMillis() + utcOffset;
</code></pre>

blocks|key|4113919|text|这段代码打印当前的UTC时间。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4113920|import+java.text.ParseException;
import+java.text.SimpleDateFormat;
import+java.util.Date;
import+java.util.TimeZone;


public+class+Test
{
++++public+static+void+main(final+String[]+args)+throws+ParseException
++++{
++++++++final+SimpleDateFormat+f+=+new+SimpleDateFormat("yyyy-MM-dd+HH:mm:ss+z");
++++++++f.setTimeZone(TimeZone.getTimeZone("UTC"));
++++++++System.out.println(f.format(new+Date()));
++++}
}|code-block|syntax|javascript|4113921|结果|4113922|2013-10-26+14:37:48+UTC|4113923|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

This code prints the current time UTC.

<pre><code>import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;


public class Test
{
 public static void main(final String[] args) throws ParseException
 {
 final SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z");
 f.setTimeZone(TimeZone.getTimeZone("UTC"));
 System.out.println(f.format(new Date()));
 }
}
</code></pre>

Result

<pre><code>2013-10-26 14:37:48 UTC
</code></pre>

blocks|key|4113969|text|使用此类可从联机NTP服务器获取正确的UTC时间：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4113970|import+java.net.DatagramPacket;
import+java.net.DatagramSocket;
import+java.net.InetAddress;


class+NTP_UTC_Time
{
private+static+final+String+TAG+=+"SntpClient";

private+static+final+int+RECEIVE_TIME_OFFSET+=+32;
private+static+final+int+TRANSMIT_TIME_OFFSET+=+40;
private+static+final+int+NTP_PACKET_SIZE+=+48;

private+static+final+int+NTP_PORT+=+123;
private+static+final+int+NTP_MODE_CLIENT+=+3;
private+static+final+int+NTP_VERSION+=+3;

//+Number+of+seconds+between+Jan+1,+1900+and+Jan+1,+1970
//+70+years+plus+17+leap+days
private+static+final+long+OFFSET_1900_TO_1970+=+((365L+*+70L)+%2B+17L)+*+24L+*+60L+*+60L;

private+long+mNtpTime;

public+boolean+requestTime(String+host,+int+timeout)+{
++++try+{
++++++++DatagramSocket+socket+=+new+DatagramSocket();
++++++++socket.setSoTimeout(timeout);
++++++++InetAddress+address+=+InetAddress.getByName(host);
++++++++byte[]+buffer+=+new+byte[NTP_PACKET_SIZE];
++++++++DatagramPacket+request+=+new+DatagramPacket(buffer,+buffer.length,+address,+NTP_PORT);

++++++++buffer[0]+=+NTP_MODE_CLIENT+%7C+(NTP_VERSION+<<+3);

++++++++writeTimeStamp(buffer,+TRANSMIT_TIME_OFFSET);

++++++++socket.send(request);

++++++++//+read+the+response
++++++++DatagramPacket+response+=+new+DatagramPacket(buffer,+buffer.length);
++++++++socket.receive(response);++++++++++
++++++++socket.close();

++++++++mNtpTime+=+readTimeStamp(buffer,+RECEIVE_TIME_OFFSET);++++++++++++
++++}+catch+(Exception+e)+{
++++++//++if+(Config.LOGD)+Log.d(TAG,+"request+time+failed:+"+%2B+e);
++++++++return+false;
++++}

++++return+true;
}


public+long+getNtpTime()+{
++++return+mNtpTime;
}


/**
+*+Reads+an+unsigned+32+bit+big+endian+number+from+the+given+offset+in+the+buffer.
+*/
private+long+read32(byte[]+buffer,+int+offset)+{
++++byte+b0+=+buffer[offset];
++++byte+b1+=+buffer[offset%2B1];
++++byte+b2+=+buffer[offset%2B2];
++++byte+b3+=+buffer[offset%2B3];

++++//+convert+signed+bytes+to+unsigned+values
++++int+i0+=+((b0+&+0x80)+==+0x80+?+(b0+&+0x7F)+%2B+0x80+:+b0);
++++int+i1+=+((b1+&+0x80)+==+0x80+?+(b1+&+0x7F)+%2B+0x80+:+b1);
++++int+i2+=+((b2+&+0x80)+==+0x80+?+(b2+&+0x7F)+%2B+0x80+:+b2);
++++int+i3+=+((b3+&+0x80)+==+0x80+?+(b3+&+0x7F)+%2B+0x80+:+b3);

++++return+((long)i0+<<+24)+%2B+((long)i1+<<+16)+%2B+((long)i2+<<+8)+%2B+(long)i3;
}

/**
+*+Reads+the+NTP+time+stamp+at+the+given+offset+in+the+buffer+and+returns+
+*+it+as+a+system+time+(milliseconds+since+January+1,+1970).
+*/++++
private+long+readTimeStamp(byte[]+buffer,+int+offset)+{
++++long+seconds+=+read32(buffer,+offset);
++++long+fraction+=+read32(buffer,+offset+%2B+4);
++++return+((seconds+-+OFFSET_1900_TO_1970)+*+1000)+%2B+((fraction+*+1000L)+/+0x100000000L);++++++++
}

/**
+*+Writes+0+as+NTP+starttime+stamp+in+the+buffer.+-->+Then+NTP+returns+Time+OFFSET+since+1900
+*/++++
private+void+writeTimeStamp(byte[]+buffer,+int+offset)+{++++++++
++++int+ofs+=++offset%2B%2B;

++++for+(int+i=ofs;i<(ofs%2B8);i%2B%2B)
++++++buffer[i]+=+(byte)(0);+++++++++++++
}

}|code-block|syntax|javascript|4113971|并通过以下方式使用它：|4113972|++++++++long+now+=+0;

++++++++NTP_UTC_Time+client+=+new+NTP_UTC_Time();

++++++++if+(client.requestTime("pool.ntp.org",+2000))+{++++++++++++++
++++++++++now+=+client.getNtpTime();
++++++++}|4113973|如果您需要UTC时间"now“作为DateTimeString使用函数：|4113974|private+String+get_UTC_Datetime_from_timestamp(long+timeStamp){

++++try{

++++++++Calendar+cal+=+Calendar.getInstance();
++++++++TimeZone+tz+=+cal.getTimeZone();

++++++++int+tzt+=+tz.getOffset(System.currentTimeMillis());

++++++++timeStamp+-=+tzt;

++++++++//+DateFormat+sdf+=+new+SimpleDateFormat("yyyy-MM-dd+HH:mm:ss",Locale.getDefault());
++++++++DateFormat+sdf+=+new+SimpleDateFormat();
++++++++Date+netDate+=+(new+Date(timeStamp));
++++++++return+sdf.format(netDate);
++++}
++++catch(Exception+ex){
++++++++return+"";
+++++}
++++}+|4113975|4113976|String+UTC_DateTime+=+get_UTC_Datetime_from_timestamp(now);|4113977|entityMap^0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|U|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|V|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|W|8|@]|9|@]|A|$E|F]]|$1|K|3|L|5|6|7|X|8|@]|9|@]|A|$]]|$1|M|3|N|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|O|3|H|5|6|7|Z|8|@]|9|@]|A|$]]|$1|P|3|Q|5|D|7|10|8|@]|9|@]|A|$E|F]]|$1|R|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|S|$]]

Use this Class to get ever the right UTC Time from a Online NTP Server: 

<pre><code>import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;


class NTP_UTC_Time
{
private static final String TAG = "SntpClient";

private static final int RECEIVE_TIME_OFFSET = 32;
private static final int TRANSMIT_TIME_OFFSET = 40;
private static final int NTP_PACKET_SIZE = 48;

private static final int NTP_PORT = 123;
private static final int NTP_MODE_CLIENT = 3;
private static final int NTP_VERSION = 3;

// Number of seconds between Jan 1, 1900 and Jan 1, 1970
// 70 years plus 17 leap days
private static final long OFFSET_1900_TO_1970 = ((365L * 70L) + 17L) * 24L * 60L * 60L;

private long mNtpTime;

public boolean requestTime(String host, int timeout) {
 try {
 DatagramSocket socket = new DatagramSocket();
 socket.setSoTimeout(timeout);
 InetAddress address = InetAddress.getByName(host);
 byte[] buffer = new byte[NTP_PACKET_SIZE];
 DatagramPacket request = new DatagramPacket(buffer, buffer.length, address, NTP_PORT);

 buffer[0] = NTP_MODE_CLIENT | (NTP_VERSION &lt;&lt; 3);

 writeTimeStamp(buffer, TRANSMIT_TIME_OFFSET);

 socket.send(request);

 // read the response
 DatagramPacket response = new DatagramPacket(buffer, buffer.length);
 socket.receive(response); 
 socket.close();

 mNtpTime = readTimeStamp(buffer, RECEIVE_TIME_OFFSET); 
 } catch (Exception e) {
 // if (Config.LOGD) Log.d(TAG, "request time failed: " + e);
 return false;
 }

 return true;
}


public long getNtpTime() {
 return mNtpTime;
}


/**
 * Reads an unsigned 32 bit big endian number from the given offset in the buffer.
 */
private long read32(byte[] buffer, int offset) {
 byte b0 = buffer[offset];
 byte b1 = buffer[offset+1];
 byte b2 = buffer[offset+2];
 byte b3 = buffer[offset+3];

 // convert signed bytes to unsigned values
 int i0 = ((b0 &amp; 0x80) == 0x80 ? (b0 &amp; 0x7F) + 0x80 : b0);
 int i1 = ((b1 &amp; 0x80) == 0x80 ? (b1 &amp; 0x7F) + 0x80 : b1);
 int i2 = ((b2 &amp; 0x80) == 0x80 ? (b2 &amp; 0x7F) + 0x80 : b2);
 int i3 = ((b3 &amp; 0x80) == 0x80 ? (b3 &amp; 0x7F) + 0x80 : b3);

 return ((long)i0 &lt;&lt; 24) + ((long)i1 &lt;&lt; 16) + ((long)i2 &lt;&lt; 8) + (long)i3;
}

/**
 * Reads the NTP time stamp at the given offset in the buffer and returns 
 * it as a system time (milliseconds since January 1, 1970).
 */ 
private long readTimeStamp(byte[] buffer, int offset) {
 long seconds = read32(buffer, offset);
 long fraction = read32(buffer, offset + 4);
 return ((seconds - OFFSET_1900_TO_1970) * 1000) + ((fraction * 1000L) / 0x100000000L); 
}

/**
 * Writes 0 as NTP starttime stamp in the buffer. --&gt; Then NTP returns Time OFFSET since 1900
 */ 
private void writeTimeStamp(byte[] buffer, int offset) { 
 int ofs = offset++;

 for (int i=ofs;i&lt;(ofs+8);i++)
 buffer[i] = (byte)(0); 
}

}
</code></pre>

And use it with:

<pre><code> long now = 0;

 NTP_UTC_Time client = new NTP_UTC_Time();

 if (client.requestTime("pool.ntp.org", 2000)) { 
 now = client.getNtpTime();
 }
</code></pre>

If you need UTC Time "now" as DateTimeString use function:

<pre><code>private String get_UTC_Datetime_from_timestamp(long timeStamp){

 try{

 Calendar cal = Calendar.getInstance();
 TimeZone tz = cal.getTimeZone();

 int tzt = tz.getOffset(System.currentTimeMillis());

 timeStamp -= tzt;

 // DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",Locale.getDefault());
 DateFormat sdf = new SimpleDateFormat();
 Date netDate = (new Date(timeStamp));
 return sdf.format(netDate);
 }
 catch(Exception ex){
 return "";
 }
 } 
</code></pre>

and use it with:

<pre><code>String UTC_DateTime = get_UTC_Datetime_from_timestamp(now);
</code></pre>

blocks|key|3268536|text|使用UTC转换当前DateTime：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3268537|DateTimeFormatter+formatter+=+DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");

DateTimeZone+dateTimeZone+=+DateTimeZone.getDefault();+//Default+Time+Zone

DateTime+currDateTime+=+new+DateTime();+//Current+DateTime

long+utcTime+=+dateTimeZone.convertLocalToUTC(currDateTime+.getMillis(),+false);

String+currTime+=+formatter.print(utcTime);+//UTC+time+converted+to+string+from+long+in+format+of+formatter

currDateTime+=+formatter.parseDateTime(currTime);+//Converted+to+DateTime+in+UTC|code-block|syntax|javascript|3268538|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Converting Current DateTime in UTC:

<pre><code>DateTimeFormatter formatter = DateTimeFormat.forPattern("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");

DateTimeZone dateTimeZone = DateTimeZone.getDefault(); //Default Time Zone

DateTime currDateTime = new DateTime(); //Current DateTime

long utcTime = dateTimeZone.convertLocalToUTC(currDateTime .getMillis(), false);

String currTime = formatter.print(utcTime); //UTC time converted to string from long in format of formatter

currDateTime = formatter.parseDateTime(currTime); //Converted to DateTime in UTC
</code></pre>

blocks|key|891934|text|这是我的实现：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|891935|public+static+String+GetCurrentTimeStamp()
{
++++Calendar+cal=Calendar.getInstance();
++++long+offset+=+cal.getTimeZone().getOffset(System.currentTimeMillis());//if+you+want+in+UTC+else+remove+it+.
++++return+new+java.sql.Timestamp(System.currentTimeMillis()%2Boffset).toString();++++
}|code-block|syntax|javascript|891936|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

this is my implementation:

<pre><code>public static String GetCurrentTimeStamp()
{
 Calendar cal=Calendar.getInstance();
 long offset = cal.getTimeZone().getOffset(System.currentTimeMillis());//if you want in UTC else remove it .
 return new java.sql.Timestamp(System.currentTimeMillis()+offset).toString(); 
}
</code></pre>

blocks|key|3268578|text|如果您使用的是joda时间，并且希望当前时间以毫秒为单位而不是本地偏移量，则可以使用以下命令：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3268579|long+instant+=+DateTimeZone.UTC.getMillisKeepLocal(DateTimeZone.getDefault(),+System.currentTimeMillis());|code-block|syntax|javascript|3268580|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you're using joda time and want the current time in milliseconds without your local offset you can use this:

<pre><code>long instant = DateTimeZone.UTC.getMillisKeepLocal(DateTimeZone.getDefault(), System.currentTimeMillis());
</code></pre>

blocks|key|3268645|text|如果你想避免解析日期而只想要一个GMT的时间戳，你可以使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3268646|final+Date+gmt+=+new+Timestamp(System.currentTimeMillis()
++++++++++++-+Calendar.getInstance().getTimeZone()
++++++++++++++++++++.getOffset(System.currentTimeMillis()));|code-block|syntax|javascript|3268647|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

If you want to avoid parsing the date and just want a timestamp in GMT, you could use:

<pre><code>final Date gmt = new Timestamp(System.currentTimeMillis()
 - Calendar.getInstance().getTimeZone()
 .getOffset(System.currentTimeMillis()));
</code></pre>

blocks|key|886840|text|下面是我的toUTC实现：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|886841|++++public+static+Date+toUTC(Date+date){
++++long+datems+=+date.getTime();
++++long+timezoneoffset+=+TimeZone.getDefault().getOffset(datems);
++++datems+-=+timezoneoffset;
++++return+new+Date(datems);
}|code-block|syntax|javascript|886842|可能有几种方法可以改进它，但它对我来说是有效的。|886843|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Here is my implementation of toUTC:

<pre><code> public static Date toUTC(Date date){
 long datems = date.getTime();
 long timezoneoffset = TimeZone.getDefault().getOffset(datems);
 datems -= timezoneoffset;
 return new Date(datems);
}
</code></pre>

There's probably several ways to improve it, but it works for me.

blocks|key|886845|text|public+static+void+main(String+args[]){
++++LocalDate+date=LocalDate.now();++
++++System.out.println("Current+date+=+"%2Bdate);
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|886846|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>public static void main(String args[]){
 LocalDate date=LocalDate.now(); 
 System.out.println("Current date = "+date);
}
</code></pre>

blocks|key|4114139|text|public+class+CurrentUtcDate+
{
++++public+static+void+main(String[]+args)+{
++++++++Date+date+=+new+Date();
++++++++SimpleDateFormat+dateFormat+=+new+SimpleDateFormat("dd-MM-yyyy+HH:mm:ss");
++++++++dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
++++++++System.out.println("UTC+Time+is:+"+%2B+dateFormat.format(date));
++++}
}|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|4114140|输出：|unstyled|4114141|UTC+Time+is:+22-01-2018+13:14:35|4114142|您可以根据需要更改日期格式。|4114143|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|N|8|@]|9|@]|A|$]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$B|C]]|$1|I|3|J|5|F|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|F|7|Q|8|@]|9|@]|A|$]]]|L|$]]

<pre><code>public class CurrentUtcDate 
{
 public static void main(String[] args) {
 Date date = new Date();
 SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
 dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
 System.out.println("UTC Time is: " + dateFormat.format(date));
 }
}
</code></pre>

Output:

<pre><code>UTC Time is: 22-01-2018 13:14:35
</code></pre>

You can change the date format as needed.

blocks|key|892004|text|使用java.time包并包含以下代码-|type|unstyled|depth|inlineStyleRanges|entityRanges|data|892005|ZonedDateTime+now+=+ZonedDateTime.now(+ZoneOffset.UTC+);|offset|length|style|CODE|892006|或|892007|LocalDateTime+now2+=+LocalDateTime.now(+ZoneOffset.UTC+);|892008|这取决于您的应用程序需求。|892009|entityMap^0|0|0|1K|0|0|0|1L|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@$D|R|E|S|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|T|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|U|8|@$D|V|E|W|F|G]]|9|@]|A|$]]|$1|L|3|M|5|6|7|X|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|O|$]]

Use java.time package and include below code-

<code>ZonedDateTime now = ZonedDateTime.now( ZoneOffset.UTC );</code>

or

<code>LocalDateTime now2 = LocalDateTime.now( ZoneOffset.UTC );</code>

depending on your application need.

blocks|key|3268748|text|UTC中的当前日期|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3268749|Instant.now().toString().replaceAll("T.*",+"");|code-block|syntax|javascript|3268750|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Current date in the UTC

<pre><code>Instant.now().toString().replaceAll("T.*", "");
</code></pre>

blocks|key|892041|text|当我需要输出一个日期对象时，我就是这样做的，当你需要在SQL数据库中保存一个日期，并且我希望它是UTC格式时，通常就是这种情况。我只需要减去当地时区的偏移时间。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|892042|++++ZonedDateTime+now+=+ZonedDateTime.now();
++++Date+nowUTC+=+new+Date(1000+*+(now.toEpochSecond()+-+now.getOffset().getTotalSeconds()));|code-block|syntax|javascript|892043|-更新Basil的建议，以更干净的方式获得相同的结果|892044|++++Date+nowUTC+=+Date.from(ZonedDateTime.now().toInstant());|892045|但在非UTC+java系统环境中进行测试后，我发现结果并不相同。使用Basil的代码，日期仍然在本地区域|892046|entityMap^0|4|8|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|V|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|Y|8|@]|D|@]|E|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|R|$]]

This is the way I do it when I need to output a Date object, which is usually the case when you need to save a Date in an SQL database and I want it to be in UTC. I just subtract the offset time of the local time zone.
<pre><code> ZonedDateTime now = ZonedDateTime.now();
 Date nowUTC = new Date(1000 * (now.toEpochSecond() - now.getOffset().getTotalSeconds()));
</code></pre>
--UPDATE
Basil's suggestion for a cleaner way to have the same result would be
<pre><code> Date nowUTC = Date.from(ZonedDateTime.now().toInstant());
</code></pre>
BUT after testing this in a non-UTC java system env, I saw that the results are not the same. With Basil's code, the Date is still on local zone

When I create a new <code>Date</code> object, it is initialized to the current time but in the local timezone. How can I get the current date and time in GMT?

How can I get the current date and time in UTC or GMT in Java?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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当我创建一个新的Date对象时，它被初始化为当前时间，但使用的是本地时区。如何在GMT中获取当前日期和时间？

问如何在Java中获取UTC或GMT格式的当前日期和时间？
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问如何在Java中获取UTC或GMT格式的当前日期和时间？EN