Java:getTimeZone而不返回默认值 [英] Java: getTimeZone without returning a default value

问题描述

我有以下说明:

TimeZone zone = TimeZone.getTimeZone("Asia/Toyo");

很显然，它应该返回null，但是它将返回默认的timeZone，这不是我的情况所希望的行为.从Java Doc:

Obviously, it should return null, but it will return the default timeZone, which is not the desired behaviour for my case. From Java Doc:

返回指定的 TimeZone ，如果无法理解给定的ID，则返回GMT区域.

Returns the specified TimeZone, or the GMT zone if the given ID cannot be understood.

如果String不能表示有效的TimeZone，是否可以获取相应的TimeZone和null值?

Is there a way to get corresponding TimeZone and null value if the String does not indicate a valid TimeZone?

我找不到一个好的解决方案来获取所有TimeZones并对其进行迭代.

I don't find a good solution to get all TimeZones and iterate over them.

推荐答案

java.time.ZoneId

现在，旧的日期时间类已被遗留，由java.time类取代.

java.time.ZoneId

The old date-time classes are now legacy, supplanted by the java.time classes.

您应该使用正确的时区名称，请调用

Instead of java.util.TimeZone, you should be using ZoneId. For parsing a proper time zone name, call ZoneId.of.

ZoneId.of ( "Africa/Casablanca" ) 

诱捕 ZoneRulesException

如果无法识别您传入的名称，则该方法将引发 ZoneRulesException .

因此，请拼写错误的 亚洲/东京 作为 Asia/Toyo ，捕获 ZoneRulesException .

So, to catch a misspelling of Asia/Tokyo as Asia/Toyo, trap for the ZoneRulesException.

ZoneId z;
try {
    z = ZoneId.of ( "Asia/Toyo" );  // Misspell "Asia/Tokyo" as "Asia/Toyo".
} catch ( ZoneRulesException e ) {
    System.out.println ( "Oops! Failed to recognize your time zone name. ZoneRulesException message: " + e.getMessage () );
    return;
}
ZonedDateTime zdt = ZonedDateTime.now ( z );

请参见此在IdeOne.com上实时运行的代码.

java.time 框架已内置在Java 8及更高版本中.这些类取代了麻烦的旧版日期时间类，例如 Calendar ，& SimpleDateFormat

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.

Joda-Time 项目，现在位于

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

要了解更多信息，请参见 Oracle教程.并在Stack Overflow中搜索许多示例和说明.规范为 JSR 310 .

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

在哪里获取java.time类?

Where to obtain the java.time classes?

• Java SE 8 和 SE 9 及更高版本
  • 内置.
  • 具有捆绑的实现的标准Java API的一部分.
  • Java 9添加了一些次要功能和修复.
  • 许多java.time功能都向后移植到Java 6&中.7在> ThreeTen-Backport 中./li>
  • > ThreeTenABP 项目适应了<专门用于Android的em> ThreeTen-Backport (上面提到).
  • 请参阅 如何使用ThreeTenABP… .
  • The ThreeTenABP project adapts ThreeTen-Backport (mentioned above) for Android specifically.
  • See How to use ThreeTenABP….

  ThreeTen-Extra 项目使用其他类扩展了java.time.该项目为将来可能在java.time中添加内容提供了一个试验场.您可能会在这里找到一些有用的类，例如 间隔 ， 年周" ， YearQuarter 和更多

  The ThreeTen-Extra project extends java.time with additional classes. This project is a proving ground for possible future additions to java.time. You may find some useful classes here such as Interval, YearWeek, YearQuarter, and more.

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