java - TimeZone.getDefault() 方法的输出

Question

当我运行以下行时，

    System.out.println(java.util.TimeZone.getDefault());

我得到了以下输出。

  sun.util.calendar.ZoneInfo[id="Asia/Calcutta",
  offset=19800000,
  dstSavings=0,
  useDaylight=false,
  transitions=6,
  lastRule=null]

和

System.out.println(Locale.getDefault()); 给出

`en_US` 

我的疑问是

Locale 怎么会是 en_US，而我的 Zone id 是 Asia/Calcutta？

在第一个输出中，我还没有理解什么是 offset、dstSavings、useDaylight、transitions 和 rules？

任何人都可以帮助理解这些。

提前致谢...

Answer 1

Locale 与 TimeZone 无关，如果您愿意，您可以在澳大利亚将您的计算机设置为法语...您不需要法国时区。

要了解有关 TimeZone 的更多信息，您应该阅读以下文章:

• > TimeZone
• > What is a TimeZone
• 实际为您提供 toString() 的类:ZoneInfo

使用夏令时

public abstract boolean useDaylightTime()

Queries if this time zone uses daylight savings time.

什么是 Daylight Saving Time .

getDSTSavings

public int getDSTSavings()

Returns the amount of time to be added to local standard time to get local wall clock time.

这就是 UTC + TimeZone + (DSTSavings - 0 或 1 小时) 之间的差异。如果您当前处于 DST 节省模式，将返回 1 小时。

规则

规则表示 DST 激活的日期和它不再存在的日期。更多信息 SimpleTimeZone .

过渡

This array describes transitions of GMT offsets of this time zone, including both raw offset changes and daylight saving time changes. A long integer consists of four bit fields.

The most significant 52-bit field represents transition time in milliseconds from Gregorian January 1 1970, 00:00:00 GMT. The next 4-bit field is reserved and must be 0. The next 4-bit field is an index value to offsets[] for the amount of daylight saving at the transition. If this value is zero, it means that no daylight saving, not the index value zero. The least significant 4-bit field is an index value to offsets[] for total GMT offset at the transition.

If this time zone doesn't observe daylight saving time and has never changed any GMT offsets in the past, this value is null.