如何在 Java 中使用 TimeZone 获取当前时间戳

Question

我想通过在Android中考虑Java中的TimeZone来获得timeStamp ，我尝试了很多方法，但仍然找不到解决方案。

Answer 1

tl;dr

Use the ZoneId & ZonedDateTime classes found in the java.time package.

ZonedDateTime.now()  // Implicitly applies the JVM’s current default time zone.

Better to specify your desired/expected time zone explicitly.

ZonedDateTime.now(
    ZoneId.of( "Africa/Tunis" ) 
)

java.time

The modern approach uses the java.time classes that years ago supplanted the terrible legacy classes such as Timestamp , Calendar , Date , TimeZone , and SimpleDateFormat .

Specify a proper time zone name in the format of Continent/Region , such as America/Montreal , Africa/Casablanca , or Pacific/Auckland . Never use the 2-4 letter abbreviation such as EST or IST as they are not true time zones, not standardized, and not even unique(!).

ZoneId z = ZoneId.of( "America/Montreal" ) ;  

Capture the current moment as seen through the wall-clock time used by the people of a particular region, that time zone named above.

ZonedDateTime zdt = ZonedDateTime.now( z ) ;

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About java.time

The java.time framework is built into Java 8 and later. These classes supplant the troublesome old legacy date-time classes such as java.util.Date , Calendar , & SimpleDateFormat .

To learn more, see the Oracle Tutorial . And search Stack Overflow for many examples and explanations. Specification is JSR 310 .

The Joda-Time project, now in maintenance mode , advises migration to the java.time classes.

You may exchange java.time objects directly with your database. Use a JDBC driver compliant with JDBC 4.2 or later. No need for strings, no need for java.sql.* classes.

Where to obtain the java.time classes?

• Java SE 8 , Java SE 9 , Java SE 10 , Java SE 11 , and later - Part of the standard Java API with a bundled implementation.
  • Java 9 adds some minor features and fixes.
• Java SE 6 and Java SE 7
  • Most of the java.time functionality is back-ported to Java 6 & 7 in ThreeTen-Backport .
• Android
  • Later versions of Android bundle implementations of the java.time classes.
  • For earlier Android (<26), the ThreeTenABP project adapts ThreeTen-Backport (mentioned above). See How to use ThreeTenABP… .

Answer 2

You can get the timestamp with time zone with this method :

public static long getTimestampWithGMT() {
    long timestamp = System.currentTimeMillis() / 1000;
    int offset = (TimeZone.getDefault().getRawOffset() + TimeZone.getDefault().getDSTSavings()) / 1000;

    return timestamp + offset;
}

Answer 3

You can use Calendar class to get current timestamp. Then you can format this timestamp to display Date, Day, Month, Year, Time etc.

Calendar c = Calendar.getInstance(); 

Check out this link: Calendar class in java with examples (GeeksForGeeks)

Answer 4

You can use Calendar.getInstance().getTimeInMillis()? It default to device timezone, or if you want to change timeZone you can do something like the following

Calendar calendar = Calendar.getInstance();
calendar.setTimeZone(TimeZone.getTimeZone("America/Los_Angeles"));
calendar.getTimeInMillis();