我正在尝试通过 Joda 中的 DateTimeZone 更改 Timestamp 的值：
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DateTime dt = new DateTime(rs.getTimestamp("anytimestampcolumn"),
DateTimeZone.forID("anytimezone"));
Timestamp ts = new Timestamp(dt.getMillis());
对于 DateTime ，值为： 2013-04-13T22:56:27.000+03:00
对于 TimeStamp ，值为： 2013-04-13 22:56:27.0
Timestamp 没有时区差异。
如何使用 TimeZone 获得正确的时间戳？ 例如我想得到“2013-05-13 01:56:27.0”。
编辑： 使用 MySQL ，列类型是 TIMESTAMP 当然， rs 是 ResultSet 。
原文由 oko 发布，翻译遵循 CC BY-SA 4.0 许可协议
一个普遍的误解是世界各地的时间（可测量的第 4 维）是不同的。时间戳作为一个时刻是独一无二的。然而，日期会影响我们“看”时间的方式，但实际上它是“一天中的时间”。
举个例子： 两个人同时看表。时间戳是一样的，对吧？但其中一个在伦敦，看到中午 12:00（格林威治标准时间，时区偏移量为 0），另一个在贝尔格莱德，看到 14:00（CET，中欧，现在夏令时，偏移量为 +2）。
他们的看法不同，但时刻是一样的。
您可以在 此答案 中找到更多详细信息。
好的，这不是 这个问题 的重复，但它毫无意义，因为您混淆了术语“时间戳 = 时刻（客观）”和“日期 [时间] = 时间（主观）”。
让我们看看您的原始问题代码分解如下：
java // Get the "original" value from database.
Timestamp momentFromDB = rs.getTimestamp("anytimestampcolumn");
// Turn it into a Joda DateTime with time zone.
DateTime dt = new DateTime(momentFromDB, DateTimeZone.forID("anytimezone"));
// And then turn it back into a timestamp but "with time zone".
Timestamp ts = new Timestamp(dt.getMillis());
我没有运行这段代码，但我确定它会打印 true 并且每次都打印相同的毫秒数：
System.out.println("momentFromDB == dt : " + (momentFromDB.getTime() == dt.getTimeInMillis());
System.out.println("momentFromDB == ts : " + (momentFromDB.getTime() == ts.getTime()));
System.out.println("dt == ts : " + (dt.getTimeInMillis() == ts.getTime()));
System.out.println("momentFromDB [ms] : " + momentFromDB.getTime());
System.out.println("ts [ms] : " + ts.getTime());
System.out.println("dt [ms] : " + dt.getTimeInMillis());
但是正如您自己所说，将它们作为字符串打印出来会导致“不同”时间，因为 DateTime 应用时区。这就是为什么“时间”被存储和传输为 Timestamp 对象（它基本上包装了一个 long ）并显示或输入为 Date[Time] .
在您自己的回答中，您人为地添加了一个偏移量并创建了一个“错误”的时间。如果您使用该时间戳创建另一个 DateTime 并将其打印出来，它将被偏移两次。
// Turn it back into a Joda DateTime with time zone.
DateTime dt = new DateTime(ts, DateTimeZone.forID("anytimezone"));
PS 如果您有时间，请浏览非常复杂的 Joda Time 源代码，看看它如何保存时间（毫秒）以及如何打印它。
import static org.junit.Assert.*;
import static org.hamcrest.CoreMatchers.*;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;
import org.junit.Before;
import org.junit.Test;
public class WorldTimeTest {
private static final int MILLIS_IN_HOUR = 1000 * 60 * 60;
private static final String ISO_FORMAT_NO_TZ = "yyyy-MM-dd'T'HH:mm:ss.SSS";
private static final String ISO_FORMAT_WITH_TZ = "yyyy-MM-dd'T'HH:mm:ss.SSSXXX";
private TimeZone londonTimeZone;
private TimeZone newYorkTimeZone;
private TimeZone sydneyTimeZone;
private long nowInMillis;
private Date now;
public static SimpleDateFormat createDateFormat(String pattern, TimeZone timeZone) throws Exception {
SimpleDateFormat result = new SimpleDateFormat(pattern);
// Must explicitly set the time zone with "setCalendar()".
result.setCalendar(Calendar.getInstance(timeZone));
return result;
}
public static SimpleDateFormat createDateFormat(String pattern) throws Exception {
return createDateFormat(pattern, TimeZone.getDefault());
}
public static SimpleDateFormat createDateFormat() throws Exception {
return createDateFormat(ISO_FORMAT_WITH_TZ, TimeZone.getDefault());
}
public void printSystemInfo() throws Exception {
final String[] propertyNames = {
"java.runtime.name", "java.runtime.version", "java.vm.name", "java.vm.version",
"os.name", "os.version", "os.arch",
"user.language", "user.country", "user.script", "user.variant",
"user.language.format", "user.country.format", "user.script.format",
"user.timezone" };
System.out.println();
System.out.println("System Information:");
for (String name : propertyNames) {
if (name == null || name.length() == 0) {
continue;
}
String value = System.getProperty(name);
if (value != null && value.length() > 0) {
System.out.println(" " + name + " = " + value);
}
}
final TimeZone defaultTZ = TimeZone.getDefault();
final int defaultOffset = defaultTZ.getOffset(nowInMillis) / MILLIS_IN_HOUR;
final int userOffset = TimeZone.getTimeZone(System
.getProperty("user.timezone")).getOffset(nowInMillis) / MILLIS_IN_HOUR;
final Locale defaultLocale = Locale.getDefault();
System.out.println(" default.timezone-offset (hours) = " + userOffset);
System.out.println(" default.timezone = " + defaultTZ.getDisplayName());
System.out.println(" default.timezone.id = " + defaultTZ.getID());
System.out.println(" default.timezone-offset (hours) = " + defaultOffset);
System.out.println(" default.locale = "
+ defaultLocale.getLanguage() + "_" + defaultLocale.getCountry()
+ " (" + defaultLocale.getDisplayLanguage()
+ "," + defaultLocale.getDisplayCountry() + ")");
System.out.println(" now = " + nowInMillis + " [ms] or "
+ createDateFormat().format(now));
System.out.println();
}
@Before
public void setUp() throws Exception {
// Remember this moment.
now = new Date();
nowInMillis = now.getTime(); // == System.currentTimeMillis();
// Print out some system information.
printSystemInfo();
// "Europe/London" time zone is DST aware, we'll use fixed offset.
londonTimeZone = TimeZone.getTimeZone("GMT");
// The same applies to "America/New York" time zone ...
newYorkTimeZone = TimeZone.getTimeZone("GMT-5");
// ... and for the "Australia/Sydney" time zone.
sydneyTimeZone = TimeZone.getTimeZone("GMT+10");
}
@Test
public void testDateFormatting() throws Exception {
int londonOffset = londonTimeZone.getOffset(nowInMillis) / MILLIS_IN_HOUR; // in hours
Calendar londonCalendar = Calendar.getInstance(londonTimeZone);
londonCalendar.setTime(now);
int newYorkOffset = newYorkTimeZone.getOffset(nowInMillis) / MILLIS_IN_HOUR;
Calendar newYorkCalendar = Calendar.getInstance(newYorkTimeZone);
newYorkCalendar.setTime(now);
int sydneyOffset = sydneyTimeZone.getOffset(nowInMillis) / MILLIS_IN_HOUR;
Calendar sydneyCalendar = Calendar.getInstance(sydneyTimeZone);
sydneyCalendar.setTime(now);
// Check each time zone offset.
assertThat(londonOffset, equalTo(0));
assertThat(newYorkOffset, equalTo(-5));
assertThat(sydneyOffset, equalTo(10));
// Check that calendars are not equals (due to time zone difference).
assertThat(londonCalendar, not(equalTo(newYorkCalendar)));
assertThat(londonCalendar, not(equalTo(sydneyCalendar)));
// Check if they all point to the same moment in time, in milliseconds.
assertThat(londonCalendar.getTimeInMillis(), equalTo(nowInMillis));
assertThat(newYorkCalendar.getTimeInMillis(), equalTo(nowInMillis));
assertThat(sydneyCalendar.getTimeInMillis(), equalTo(nowInMillis));
// Check if they all point to the same moment in time, as Date.
assertThat(londonCalendar.getTime(), equalTo(now));
assertThat(newYorkCalendar.getTime(), equalTo(now));
assertThat(sydneyCalendar.getTime(), equalTo(now));
// Check if hours are all different (skip local time because
// this test could be executed in those exact time zones).
assertThat(newYorkCalendar.get(Calendar.HOUR_OF_DAY),
not(equalTo(londonCalendar.get(Calendar.HOUR_OF_DAY))));
assertThat(sydneyCalendar.get(Calendar.HOUR_OF_DAY),
not(equalTo(londonCalendar.get(Calendar.HOUR_OF_DAY))));
// Display London time in multiple forms.
SimpleDateFormat dfLondonNoTZ = createDateFormat(ISO_FORMAT_NO_TZ, londonTimeZone);
SimpleDateFormat dfLondonWithTZ = createDateFormat(ISO_FORMAT_WITH_TZ, londonTimeZone);
System.out.println("London (" + londonTimeZone.getDisplayName(false, TimeZone.SHORT)
+ ", " + londonOffset + "):");
System.out.println(" time (ISO format w/o TZ) = "
+ dfLondonNoTZ.format(londonCalendar.getTime()));
System.out.println(" time (ISO format w/ TZ) = "
+ dfLondonWithTZ.format(londonCalendar.getTime()));
System.out.println(" time (default format) = "
+ londonCalendar.getTime() + " / " + londonCalendar.toString());
// Using system default time zone.
System.out.println(" time (default TZ) = "
+ createDateFormat(ISO_FORMAT_NO_TZ).format(londonCalendar.getTime())
+ " / " + createDateFormat().format(londonCalendar.getTime()));
// Display New York time in multiple forms.
SimpleDateFormat dfNewYorkNoTZ = createDateFormat(ISO_FORMAT_NO_TZ, newYorkTimeZone);
SimpleDateFormat dfNewYorkWithTZ = createDateFormat(ISO_FORMAT_WITH_TZ, newYorkTimeZone);
System.out.println("New York (" + newYorkTimeZone.getDisplayName(false, TimeZone.SHORT)
+ ", " + newYorkOffset + "):");
System.out.println(" time (ISO format w/o TZ) = "
+ dfNewYorkNoTZ.format(newYorkCalendar.getTime()));
System.out.println(" time (ISO format w/ TZ) = "
+ dfNewYorkWithTZ.format(newYorkCalendar.getTime()));
System.out.println(" time (default format) = "
+ newYorkCalendar.getTime() + " / " + newYorkCalendar.toString());
// Using system default time zone.
System.out.println(" time (default TZ) = "
+ createDateFormat(ISO_FORMAT_NO_TZ).format(newYorkCalendar.getTime())
+ " / " + createDateFormat().format(newYorkCalendar.getTime()));
// Display Sydney time in multiple forms.
SimpleDateFormat dfSydneyNoTZ = createDateFormat(ISO_FORMAT_NO_TZ, sydneyTimeZone);
SimpleDateFormat dfSydneyWithTZ = createDateFormat(ISO_FORMAT_WITH_TZ, sydneyTimeZone);
System.out.println("Sydney (" + sydneyTimeZone.getDisplayName(false, TimeZone.SHORT)
+ ", " + sydneyOffset + "):");
System.out.println(" time (ISO format w/o TZ) = "
+ dfSydneyNoTZ.format(sydneyCalendar.getTime()));
System.out.println(" time (ISO format w/ TZ) = "
+ dfSydneyWithTZ.format(sydneyCalendar.getTime()));
System.out.println(" time (default format) = "
+ sydneyCalendar.getTime() + " / " + sydneyCalendar.toString());
// Using system default time zone.
System.out.println(" time (default TZ) = "
+ createDateFormat(ISO_FORMAT_NO_TZ).format(sydneyCalendar.getTime())
+ " / " + createDateFormat().format(sydneyCalendar.getTime()));
}
@Test
public void testDateParsing() throws Exception {
// Create date parsers that look for time zone information in a date-time string.
final SimpleDateFormat londonFormatTZ = createDateFormat(ISO_FORMAT_WITH_TZ, londonTimeZone);
final SimpleDateFormat newYorkFormatTZ = createDateFormat(ISO_FORMAT_WITH_TZ, newYorkTimeZone);
final SimpleDateFormat sydneyFormatTZ = createDateFormat(ISO_FORMAT_WITH_TZ, sydneyTimeZone);
// Create date parsers that ignore time zone information in a date-time string.
final SimpleDateFormat londonFormatLocal = createDateFormat(ISO_FORMAT_NO_TZ, londonTimeZone);
final SimpleDateFormat newYorkFormatLocal = createDateFormat(ISO_FORMAT_NO_TZ, newYorkTimeZone);
final SimpleDateFormat sydneyFormatLocal = createDateFormat(ISO_FORMAT_NO_TZ, sydneyTimeZone);
// We are looking for the moment this millenium started, the famous Y2K,
// when at midnight everyone welcomed the New Year 2000, i.e. 2000-01-01 00:00:00.
// Which of these is the right one?
// a) "2000-01-01T00:00:00.000-00:00"
// b) "2000-01-01T00:00:00.000-05:00"
// c) "2000-01-01T00:00:00.000+10:00"
// None of them? All of them?
// For those who guessed it - yes, it is a trick question because we didn't specify
// the "where" part, or what kind of time (local/global) we are looking for.
// The first (a) is the local Y2K moment in London, which is at the same time global.
// The second (b) is the local Y2K moment in New York, but London is already celebrating for 5 hours.
// The third (c) is the local Y2K moment in Sydney, and they started celebrating 15 hours before New York did.
// The point here is that each answer is correct because everyone thinks of that moment in terms of "celebration at midnight".
// The key word here is "midnight"! That moment is actually a "time of day" moment illustrating our perception of time based on the movement of our Sun.
// These are global Y2K moments, i.e. the same moment all over the world, UTC/GMT midnight.
final String MIDNIGHT_GLOBAL = "2000-01-01T00:00:00.000-00:00";
final Date milleniumInLondon = londonFormatTZ.parse(MIDNIGHT_GLOBAL);
final Date milleniumInNewYork = newYorkFormatTZ.parse(MIDNIGHT_GLOBAL);
final Date milleniumInSydney = sydneyFormatTZ.parse(MIDNIGHT_GLOBAL);
// Check if they all point to the same moment in time.
// And that parser ignores its own configured time zone and uses the information from the date-time string.
assertThat(milleniumInNewYork, equalTo(milleniumInLondon));
assertThat(milleniumInSydney, equalTo(milleniumInLondon));
// These are all local Y2K moments, a.k.a. midnight at each location on Earth, with time zone information.
final String MIDNIGHT_LONDON = "2000-01-01T00:00:00.000-00:00";
final String MIDNIGHT_NEW_YORK = "2000-01-01T00:00:00.000-05:00";
final String MIDNIGHT_SYDNEY = "2000-01-01T00:00:00.000+10:00";
final Date midnightInLondonTZ = londonFormatLocal.parse(MIDNIGHT_LONDON);
final Date midnightInNewYorkTZ = newYorkFormatLocal.parse(MIDNIGHT_NEW_YORK);
final Date midnightInSydneyTZ = sydneyFormatLocal.parse(MIDNIGHT_SYDNEY);
// Check if they all point to the same moment in time.
assertThat(midnightInNewYorkTZ, not(equalTo(midnightInLondonTZ)));
assertThat(midnightInSydneyTZ, not(equalTo(midnightInLondonTZ)));
// Check if the time zone offset is correct.
assertThat(midnightInLondonTZ.getTime() - midnightInNewYorkTZ.getTime(),
equalTo((long) newYorkTimeZone.getOffset(milleniumInLondon.getTime())));
assertThat(midnightInLondonTZ.getTime() - midnightInSydneyTZ.getTime(),
equalTo((long) sydneyTimeZone.getOffset(milleniumInLondon.getTime())));
// These are also local Y2K moments, just withouth the time zone information.
final String MIDNIGHT_ANYWHERE = "2000-01-01T00:00:00.000";
final Date midnightInLondon = londonFormatLocal.parse(MIDNIGHT_ANYWHERE);
final Date midnightInNewYork = newYorkFormatLocal.parse(MIDNIGHT_ANYWHERE);
final Date midnightInSydney = sydneyFormatLocal.parse(MIDNIGHT_ANYWHERE);
// Check if these are the same as the local moments with time zone information.
assertThat(midnightInLondon, equalTo(midnightInLondonTZ));
assertThat(midnightInNewYork, equalTo(midnightInNewYorkTZ));
assertThat(midnightInSydney, equalTo(midnightInSydneyTZ));
// Check if they all point to the same moment in time.
assertThat(midnightInNewYork, not(equalTo(midnightInLondon)));
assertThat(midnightInSydney, not(equalTo(midnightInLondon)));
// Check if the time zone offset is correct.
assertThat(midnightInLondon.getTime() - midnightInNewYork.getTime(),
equalTo((long) newYorkTimeZone.getOffset(milleniumInLondon.getTime())));
assertThat(midnightInLondon.getTime() - midnightInSydney.getTime(),
equalTo((long) sydneyTimeZone.getOffset(milleniumInLondon.getTime())));
// Final check - if Y2K moment is in London ..
final String Y2K_LONDON = "2000-01-01T00:00:00.000Z";
// .. New York local time would be still 5 hours in 1999 ..
final String Y2K_NEW_YORK = "1999-12-31T19:00:00.000-05:00";
// .. and Sydney local time would be 10 hours in 2000.
final String Y2K_SYDNEY = "2000-01-01T10:00:00.000+10:00";
final String londonTime = londonFormatTZ.format(milleniumInLondon);
final String newYorkTime = newYorkFormatTZ.format(milleniumInLondon);
final String sydneyTime = sydneyFormatTZ.format(milleniumInLondon);
// WHat do you think, will the test pass?
assertThat(londonTime, equalTo(Y2K_LONDON));
assertThat(newYorkTime, equalTo(Y2K_NEW_YORK));
assertThat(sydneyTime, equalTo(Y2K_SYDNEY));
}
}
原文由 Cebence 发布，翻译遵循 CC BY-SA 3.0 许可协议
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实际上这不是一个重复的问题。这就是我多次解决问题的方法：
这是从所需时区偏移的方法。
让我们回到我们的代码，我们从查询的结果集中获取时间戳，并将它与时区一起使用来创建我们的日期时间。
现在我们将我们的偏移量添加到日期时间，并从中获取时间戳。
可能这不是获得它的实际方法，但它解决了我的问题。我希望它能帮助任何被困在这里的人。