blocks|key|3195594|text|好吧，我认为复制像SimpleDateFormat这样的类中已经存在的代码不是一个好主意。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3195595|另一方面，我个人建议如果可以的话，完全避免使用Calendar和Date，而使用Joda+Time，作为一种设计得更好的日期和时间应用编程接口。例如，您需要知道SimpleDateFormat不是线程安全的，因此您要么需要线程本地变量、同步，要么每次使用它时都需要一个新实例。Joda解析器和格式器是线程安全的。|3195596|entityMap|0|LINK|mutability|MUTABLE|url|http://download.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html|1|http://joda-time.sf.net/^0|9|G|9|G|0|0|N|8|W|4|28|G|14|9|1|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]]|D|@$9|U|A|V|1|W]]|E|$]]|$1|F|3|G|5|6|7|X|8|@$9|Y|A|Z|B|C]|$9|10|A|11|B|C]|$9|12|A|13|B|C]]|D|@$9|14|A|15|1|16]]|E|$]]|$1|H|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]|P|$5|K|L|M|E|$N|Q]]]]

Well, I think it would be a bad idea to replicate the code which is already present in classes like <a href="http://download.oracle.com/javase/6/docs/api/java/text/SimpleDateFormat.html"><code>SimpleDateFormat</code></a>.

On the other hand, personally I'd suggest avoiding <code>Calendar</code> and <code>Date</code> entirely if you can, and using <a href="http://joda-time.sf.net">Joda Time</a> instead, as a far better designed date and time API. For example, you need to be aware that <code>SimpleDateFormat</code> is not thread-safe, so you either need thread-locals, synchronization, or a new instance each time you use it. Joda parsers and formatters are thread-safe.

blocks|key|2982289|text|是的，自己解析它将是一种糟糕的做法。看看SimpleDateFormat，它会将字符串转换为日期，您可以将日期设置为日历实例。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|2982290|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html^0|K|G|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

Yes it would be bad practice to parse it yourself. Take a look at <a href="http://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html" rel="nofollow">SimpleDateFormat</a>, it will turn the String into a Date and you can set the Date into a Calendar instance.

blocks|key|3195637|text|Calendar+cal+=+Calendar.getInstance();
SimpleDateFormat+sdf+=+new+SimpleDateFormat("EEE+MMM+dd+HH:mm:ss+z+yyyy",+Locale.ENGLISH);
cal.setTime(sdf.parse("Mon+Mar+14+16:02:37+GMT+2011"));//+all+done|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|3195638|注:根据您的环境/要求设置Locale|unstyled|offset|length|style|CODE|3195639|3195640|另请参阅|3195641|3195642|Javadoc|unordered-list-item|3195643|3195644|entityMap|0|LINK|mutability|MUTABLE|url|http://download.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html^0|0|D|6|0|0|0|0|0|7|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|11|8|@$G|12|H|13|I|J]]|9|@]|A|$]]|$1|K|3|-4|5|F|7|14|8|@]|9|@]|A|$]]|$1|L|3|M|5|F|7|15|8|@]|9|@]|A|$]]|$1|N|3|-4|5|F|7|16|8|@]|9|@]|A|$]]|$1|O|3|P|5|Q|7|17|8|@]|9|@$G|18|H|19|1|1A]]|A|$]]|$1|R|3|-4|5|F|7|1B|8|@]|9|@]|A|$]]|$1|S|3|-4|5|F|7|1C|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]]]

<pre><code>Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy", Locale.ENGLISH);
cal.setTime(sdf.parse("Mon Mar 14 16:02:37 GMT 2011"));// all done
</code></pre>

note: set <code>Locale</code> according to your environment/requirement

<hr>

See Also

<ul>
<li><a href="http://download.oracle.com/javase/8/docs/api/java/text/SimpleDateFormat.html" rel="noreferrer">Javadoc</a> </li>
</ul>

blocks|key|278048|text|SimpleDateFormat很棒，只需注意HH在处理小时时与hh不同。HH将返回基于24小时的小时，而hh将返回基于12小时的小时。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|278049|例如，以下代码将返回12小时时间：|278050|SimpleDateFormat+sdf+=+new+SimpleDateFormat("hh:mm+aa");|code-block|syntax|javascript|278051|而这将返回24小时时间：|278052|SimpleDateFormat+sdf+=+new+SimpleDateFormat("HH:mm");|278053|entityMap^0|0|G|N|2|W|2|11|2|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|11|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|13|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|15|8|@]|D|@]|E|$]]]|R|$]]

<code>SimpleDateFormat</code> is great, just note that <code>HH</code> is different from <code>hh</code> when working with hours. <code>HH</code> will return 24 hour based hours and hh will return 12 hour based hours.

For example, the following will return 12 hour time:

<pre><code>SimpleDateFormat sdf = new SimpleDateFormat("hh:mm aa");
</code></pre>

While this will return 24 hour time:

<pre><code>SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");
</code></pre>

blocks|key|2982353|text|不需要创建新的日历，SimpleDateFormat已经在下面使用了日历。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2982354|SimpleDateFormat+sdf+=+new+SimpleDateFormat("EEE+MMM+dd+HH:mm:ss+z+yyyy",+Locale.EN_US);
Date+date+=+sdf.parse("Mon+Mar+14+16:02:37+GMT+2011"));//+all+done
Calendar+cal+=+sdf.getCalendar();|code-block|syntax|javascript|2982355|(我还不能评论，这就是为什么我创建了一个新的答案)|2982356|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|$]]

No new Calendar needs to be created, SimpleDateFormat already uses a Calendar underneath.

<pre><code>SimpleDateFormat sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy", Locale.EN_US);
Date date = sdf.parse("Mon Mar 14 16:02:37 GMT 2011"));// all done
Calendar cal = sdf.getCalendar();
</code></pre>

(I can't comment yet, that's why I created a new answer)

blocks|key|280008|text|简单的方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|280009|public+Calendar+stringToCalendar(String+date,+String+pattern)+throws+ParseException+{
++++String+DEFAULT_LOCALE_NAME+=+"pt";
++++String+DEFAULT_COUNTRY+=+"BR";
++++Locale+DEFAULT_LOCALE+=+new+Locale(DEFAULT_LOCALE_NAME,+DEFAULT_COUNTRY);
++++SimpleDateFormat+format+=+new+SimpleDateFormat(pattern,+LocaleUtils.DEFAULT_LOCALE);
++++Date+d+=+format.parse(date);
++++Calendar+c+=+getCalendar();
++++c.setTime(d);
++++return+c;
}|code-block|syntax|javascript|280010|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|$]]

Simple method:

<pre><code>public Calendar stringToCalendar(String date, String pattern) throws ParseException {
 String DEFAULT_LOCALE_NAME = "pt";
 String DEFAULT_COUNTRY = "BR";
 Locale DEFAULT_LOCALE = new Locale(DEFAULT_LOCALE_NAME, DEFAULT_COUNTRY);
 SimpleDateFormat format = new SimpleDateFormat(pattern, LocaleUtils.DEFAULT_LOCALE);
 Date d = format.parse(date);
 Calendar c = getCalendar();
 c.setTime(d);
 return c;
}
</code></pre>

blocks|key|274396|text|tl;dr|type|unstyled|depth|inlineStyleRanges|entityRanges|data|274397|现代方法使用java.time类。|274398|YearMonth.from(
++++ZonedDateTime.parse(+
++++++++"Mon+Mar+14+16:02:37+GMT+2011"+,+
++++++++DateTimeFormatter.ofPattern(+"E+MMM+d+HH:mm:ss+z+uuuu"+)
+++++)
).toString()|code-block|syntax|javascript|274399|274400|+2011-03|blockquote|274401|274402|274403|避免遗留的日期-时间类|274404|现代的方法是使用java.time类。旧的日期-时间类，如Calendar，已被证明设计不佳、令人困惑和麻烦。|offset|length|style|CODE|274405|定义一个自定义格式化程序以匹配您的字符串输入。|274406|String+input+=+"Mon+Mar+14+16:02:37+GMT+2011";
DateTimeFormatter+f+=+DateTimeFormatter.ofPattern(+"E+MMM+d+HH:mm:ss+z+uuuu"+);|274407|解析为ZonedDateTime。|274408|ZonedDateTime+zdt+=+ZonedDateTime.parse(+input+,+f+);|274409|您感兴趣的是年份和月份。为此，java.time类包括YearMonth类。|274410|YearMonth+ym+=+YearMonth.from(+zdt+);|274411|如果需要，您可以询问年份和月份的数字。|274412|int+year+=+ym.getYear();
int+month+=+ym.getMonthValue();|274413|但是toString方法生成标准ISO+8601格式的字符串。|274414|String+output+=+ym.toString();|274415|把这些放在一起。|274416|String+input+=+"Mon+Mar+14+16:02:37+GMT+2011";
DateTimeFormatter+f+=+DateTimeFormatter.ofPattern(+"E+MMM+d+HH:mm:ss+z+uuuu"+);
ZonedDateTime+zdt+=+ZonedDateTime.parse(+input+,+f+);
YearMonth+ym+=+YearMonth.from(+zdt+);
int+year+=+ym.getYear();
int+month+=+ym.getMonthValue();|274417|转储到控制台。|274418|System.out.println(+"input:+"+%2B+input+);
System.out.println(+"zdt:+"+%2B+zdt+);
System.out.println(+"ym:+"+%2B+ym+);|274419|274420|输入:+Mon+Mar+14+16:02:37+GMT+2011+zdt:+2011-03-14T16:02:37ZGMT+ym:+2011-03|274421|274422|274423|实时代码|274424|参见this+code+running+in+IdeOne.com。|274425|转换|274426|如果必须使用Calendar对象，则可以使用添加到旧类中的新方法转换为GregorianCalendar。|274427|GregorianCalendar+gc+=+GregorianCalendar.from(+zdt+);|274428|274429|关于java.time|274430|框架内置于Java8和更高版本中。这些类取代了麻烦的旧legacy日期时间类，如java.util.Date、Calendar和SimpleDateFormat。|274431|要了解更多信息，请参阅。和搜索堆栈溢出，以获得许多示例和解释。规范为JSR+310。|274432|现在在maintenance+mode中的项目建议迁移到java.time类。|274433|您可以直接与数据库交换java.time对象。使用与JDBC+4.2或更高版本兼容的JDBC+driver。不需要字符串，也不需要java.sql.*类。Hibernate+5和JPA2.2支持java.time。|274434|从哪里获取java.time类？|274435|274436|，、、和更高版本-标准Java+API的一部分，具有捆绑的实现。|unordered-list-item|274437|带来了一些次要的特性和fixes.|274438|274439|274440|274441|和.|274442|中的+|274443|大多数java.time功能已向后移植到Java6和7|274444|274445|274446|+|274447|更高版本的Android+(26%2B)捆绑了java.time类的实现。|274448|对于较早的Android+(<26)，的进程带来了最初没有内置到Android中的subset+of+the+功能。|274449|如果去糖化没有提供你需要的东西，项目会让+(上面提到的)适应安卓系统。请参阅.|274450|274451|274452|274453|entityMap|0|LINK|mutability|MUTABLE|url|https://en.wikipedia.org/wiki/ISO_8601|1|http://ideone.com/WJBUzK|2|http://docs.oracle.com/javase/8/docs/api/java/util/GregorianCalendar.html|3|https://en.wikipedia.org/wiki/Legacy_system|4|https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Date.html|5|https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Calendar.html|6|https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/text/SimpleDateFormat.html|7|https://jcp.org/en/jsr/detail?id=310|8|https://en.wikipedia.org/wiki/Maintenance_mode|9|https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/package-summary.html|10|http://openjdk.java.net/jeps/170|11|https://en.wikipedia.org/wiki/JDBC_driver|12|https://developer.android.com/studio/write/java8-support-table^0|0|0|0|0|0|0|0|0|T|8|0|0|0|3|D|0|0|R|9|0|0|0|0|2|8|G|8|0|0|0|0|0|0|0|0|0|0|0|0|2|V|1|0|0|6|8|Z|H|Z|H|2|0|0|0|0|14|E|1J|8|1S|G|R|6|3|14|E|4|1J|8|5|1S|G|6|0|Y|7|7|0|3|G|8|S|9|9|0|1T|A|Q|8|A|16|B|B|0|0|0|1|1|0|0|0|0|0|0|0|0|1|1|15|E|C|2|2|1|0|0^^$0|@$1|2|3|4|5|6|7|44|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|45|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|46|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|47|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|48|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|49|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|4A|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|4B|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|4C|8|@$S|4D|T|4E|U|V]]|9|@]|A|$]]|$1|W|3|X|5|6|7|4F|8|@]|9|@]|A|$]]|$1|Y|3|Z|5|F|7|4G|8|@]|9|@]|A|$G|H]]|$1|10|3|11|5|6|7|4H|8|@$S|4I|T|4J|U|V]]|9|@]|A|$]]|$1|12|3|13|5|F|7|4K|8|@]|9|@]|A|$G|H]]|$1|14|3|15|5|6|7|4L|8|@$S|4M|T|4N|U|V]]|9|@]|A|$]]|$1|16|3|17|5|F|7|4O|8|@]|9|@]|A|$G|H]]|$1|18|3|19|5|6|7|4P|8|@]|9|@]|A|$]]|$1|1A|3|1B|5|F|7|4Q|8|@]|9|@]|A|$G|H]]|$1|1C|3|1D|5|6|7|4R|8|@$S|4S|T|4T|U|V]]|9|@$S|4U|T|4V|1|4W]]|A|$]]|$1|1E|3|1F|5|F|7|4X|8|@]|9|@]|A|$G|H]]|$1|1G|3|1H|5|6|7|4Y|8|@]|9|@]|A|$]]|$1|1I|3|1J|5|F|7|4Z|8|@]|9|@]|A|$G|H]]|$1|1K|3|1L|5|6|7|50|8|@]|9|@]|A|$]]|$1|1M|3|1N|5|F|7|51|8|@]|9|@]|A|$G|H]]|$1|1O|3|-4|5|6|7|52|8|@]|9|@]|A|$]]|$1|1P|3|1Q|5|L|7|53|8|@]|9|@]|A|$]]|$1|1R|3|-4|5|6|7|54|8|@]|9|@]|A|$]]|$1|1S|3|-4|5|6|7|55|8|@]|9|@]|A|$]]|$1|1T|3|1U|5|6|7|56|8|@]|9|@]|A|$]]|$1|1V|3|1W|5|6|7|57|8|@]|9|@$S|58|T|59|1|5A]]|A|$]]|$1|1X|3|1Y|5|6|7|5B|8|@]|9|@]|A|$]]|$1|1Z|3|20|5|6|7|5C|8|@$S|5D|T|5E|U|V]|$S|5F|T|5G|U|V]]|9|@$S|5H|T|5I|1|5J]]|A|$]]|$1|21|3|22|5|F|7|5K|8|@]|9|@]|A|$G|H]]|$1|23|3|-4|5|6|7|5L|8|@]|9|@]|A|$]]|$1|24|3|25|5|6|7|5M|8|@]|9|@]|A|$]]|$1|26|3|27|5|6|7|5N|8|@$S|5O|T|5P|U|V]|$S|5Q|T|5R|U|V]|$S|5S|T|5T|U|V]]|9|@$S|5U|T|5V|1|5W]|$S|5X|T|5Y|1|5Z]|$S|60|T|61|1|62]|$S|63|T|64|1|65]]|A|$]]|$1|28|3|29|5|6|7|66|8|@]|9|@$S|67|T|68|1|69]]|A|$]]|$1|2A|3|2B|5|6|7|6A|8|@]|9|@$S|6B|T|6C|1|6D]|$S|6E|T|6F|1|6G]]|A|$]]|$1|2C|3|2D|5|6|7|6H|8|@$S|6I|T|6J|U|V]]|9|@$S|6K|T|6L|1|6M]|$S|6N|T|6O|1|6P]]|A|$]]|$1|2E|3|2F|5|6|7|6Q|8|@]|9|@]|A|$]]|$1|2G|3|-4|5|6|7|6R|8|@]|9|@]|A|$]]|$1|2H|3|2I|5|2J|7|6S|8|@]|9|@]|A|$]]|$1|2K|3|2L|5|2J|7|6T|8|@]|9|@]|A|$]]|$1|2M|3|-4|5|6|7|6U|8|@]|9|@]|A|$]]|$1|2N|3|-4|5|6|7|6V|8|@]|9|@]|A|$]]|$1|2O|3|-4|5|6|7|6W|8|@]|9|@]|A|$]]|$1|2P|3|2Q|5|2J|7|6X|8|@]|9|@]|A|$]]|$1|2R|3|2S|5|6|7|6Y|8|@]|9|@]|A|$]]|$1|2T|3|2U|5|2J|7|6Z|8|@]|9|@]|A|$]]|$1|2V|3|-4|5|6|7|70|8|@]|9|@]|A|$]]|$1|2W|3|-4|5|6|7|71|8|@]|9|@]|A|$]]|$1|2X|3|2Y|5|2J|7|72|8|@]|9|@]|A|$]]|$1|2Z|3|30|5|2J|7|73|8|@]|9|@]|A|$]]|$1|31|3|32|5|2J|7|74|8|@]|9|@$S|75|T|76|1|77]]|A|$]]|$1|33|3|34|5|2J|7|78|8|@]|9|@]|A|$]]|$1|35|3|-4|5|6|7|79|8|@]|9|@]|A|$]]|$1|36|3|-4|5|6|7|7A|8|@]|9|@]|A|$]]|$1|37|3|-4|5|6|7|7B|8|@]|9|@]|A|$]]|$1|38|3|-4|5|6|7|7C|8|@]|9|@]|A|$]]]|39|$3A|$5|3B|3C|3D|A|$3E|3F]]|3G|$5|3B|3C|3D|A|$3E|3H]]|3I|$5|3B|3C|3D|A|$3E|3J]]|3K|$5|3B|3C|3D|A|$3E|3L]]|3M|$5|3B|3C|3D|A|$3E|3N]]|3O|$5|3B|3C|3D|A|$3E|3P]]|3Q|$5|3B|3C|3D|A|$3E|3R]]|3S|$5|3B|3C|3D|A|$3E|3T]]|3U|$5|3B|3C|3D|A|$3E|3V]]|3W|$5|3B|3C|3D|A|$3E|3X]]|3Y|$5|3B|3C|3D|A|$3E|3Z]]|40|$5|3B|3C|3D|A|$3E|41]]|42|$5|3B|3C|3D|A|$3E|43]]]]

<h1>tl;dr</h1>
The modern approach uses the java.time classes.
<pre><code>YearMonth.from(
 ZonedDateTime.parse( 
 &quot;Mon Mar 14 16:02:37 GMT 2011&quot; , 
 DateTimeFormatter.ofPattern( &quot;E MMM d HH:mm:ss z uuuu&quot; )
 )
).toString()
</code></pre>
<blockquote>
2011-03
</blockquote>
<h1>Avoid legacy date-time classes</h1>
The modern way is with java.time classes. The old date-time classes such as <code>Calendar</code> have proven to be poorly-designed, confusing, and troublesome.
Define a custom formatter to match your string input.
<pre><code>String input = &quot;Mon Mar 14 16:02:37 GMT 2011&quot;;
DateTimeFormatter f = DateTimeFormatter.ofPattern( &quot;E MMM d HH:mm:ss z uuuu&quot; );
</code></pre>
Parse as a <code>ZonedDateTime</code>.
<pre><code>ZonedDateTime zdt = ZonedDateTime.parse( input , f );
</code></pre>
You are interested in the year and month. The java.time classes include <code>YearMonth</code> class for that purpose.
<pre><code>YearMonth ym = YearMonth.from( zdt );
</code></pre>
You can interrogate for the year and month numbers if needed.
<pre><code>int year = ym.getYear();
int month = ym.getMonthValue();
</code></pre>
But the <code>toString</code> method generates a string in standard <a href="https://en.wikipedia.org/wiki/ISO_8601" rel="nofollow noreferrer">ISO 8601</a> format.
<pre><code>String output = ym.toString();
</code></pre>
Put this all together.
<pre><code>String input = &quot;Mon Mar 14 16:02:37 GMT 2011&quot;;
DateTimeFormatter f = DateTimeFormatter.ofPattern( &quot;E MMM d HH:mm:ss z uuuu&quot; );
ZonedDateTime zdt = ZonedDateTime.parse( input , f );
YearMonth ym = YearMonth.from( zdt );
int year = ym.getYear();
int month = ym.getMonthValue();
</code></pre>
Dump to console.
<pre><code>System.out.println( &quot;input: &quot; + input );
System.out.println( &quot;zdt: &quot; + zdt );
System.out.println( &quot;ym: &quot; + ym );
</code></pre>
<blockquote>
input: Mon Mar 14 16:02:37 GMT 2011
</blockquote>
<blockquote>
zdt: 2011-03-14T16:02:37Z[GMT]
</blockquote>
<blockquote>
ym: 2011-03
</blockquote>
<h2>Live code</h2>
See <a href="http://ideone.com/WJBUzK" rel="nofollow noreferrer">this code running in IdeOne.com</a>.
<h2>Conversion</h2>
If you must have a <code>Calendar</code> object, you can convert to a <a href="http://docs.oracle.com/javase/8/docs/api/java/util/GregorianCalendar.html" rel="nofollow noreferrer"><code>GregorianCalendar</code></a> using new methods added to the old classes.
<pre><code>GregorianCalendar gc = GregorianCalendar.from( zdt );
</code></pre>
<hr />
<h1>About java.time</h1>
The <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/package-summary.html" rel="nofollow noreferrer">java.time</a> framework is built into Java 8 and later. These classes supplant the troublesome old <a href="https://en.wikipedia.org/wiki/Legacy_system" rel="nofollow noreferrer">legacy</a> date-time classes such as <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Date.html" rel="nofollow noreferrer"><code>java.util.Date</code></a>, <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/util/Calendar.html" rel="nofollow noreferrer"><code>Calendar</code></a>, &amp; <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/text/SimpleDateFormat.html" rel="nofollow noreferrer"><code>SimpleDateFormat</code></a>.
To learn more, see the <a href="http://docs.oracle.com/javase/tutorial/datetime/TOC.html" rel="nofollow noreferrer">Oracle Tutorial</a>. And search Stack Overflow for many examples and explanations. Specification is <a href="https://jcp.org/en/jsr/detail?id=310" rel="nofollow noreferrer">JSR 310</a>.
The <a href="http://www.joda.org/joda-time/" rel="nofollow noreferrer">Joda-Time</a> project, now in <a href="https://en.wikipedia.org/wiki/Maintenance_mode" rel="nofollow noreferrer">maintenance mode</a>, advises migration to the <a href="https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/time/package-summary.html" rel="nofollow noreferrer">java.time</a> classes.
You may exchange java.time objects directly with your database. Use a <a href="https://en.wikipedia.org/wiki/JDBC_driver" rel="nofollow noreferrer">JDBC driver</a> compliant with <a href="http://openjdk.java.net/jeps/170" rel="nofollow noreferrer">JDBC 4.2</a> or later. No need for strings, no need for <code>java.sql.*</code> classes. Hibernate 5 &amp; JPA 2.2 support java.time.
Where to obtain the java.time classes?
<ul>
<li><a href="https://en.wikipedia.org/wiki/Java_version_history#Java_SE_8" rel="nofollow noreferrer">Java SE 8</a>, <a href="https://en.wikipedia.org/wiki/Java_version_history#Java_SE_9" rel="nofollow noreferrer">Java SE 9</a>, <a href="https://en.wikipedia.org/wiki/Java_version_history#Java_SE_10" rel="nofollow noreferrer">Java SE 10</a>, <a href="https://en.wikipedia.org/wiki/Java_version_history#Java_SE_11" rel="nofollow noreferrer">Java SE 11</a>, and later - Part of the standard Java API with a bundled implementation.
<ul>
<li><a href="https://en.wikipedia.org/wiki/Java_version_history#Java_SE_9" rel="nofollow noreferrer">Java 9</a> brought some minor features and fixes.</li>
</ul>
</li>
<li><a href="https://en.wikipedia.org/wiki/Java_version_history#Java_SE_6" rel="nofollow noreferrer">Java SE 6</a> and <a href="https://en.wikipedia.org/wiki/Java_version_history#Java_SE_7" rel="nofollow noreferrer">Java SE 7</a>
<ul>
<li>Most of the java.time functionality is back-ported to Java 6 &amp; 7 in <a href="http://www.threeten.org/threetenbp/" rel="nofollow noreferrer">ThreeTen-Backport</a>.</li>
</ul>
</li>
<li><a href="https://en.wikipedia.org/wiki/Android_(operating_system)" rel="nofollow noreferrer">Android</a>
<ul>
<li>Later versions of Android (26+) bundle implementations of the java.time classes.</li>
<li>For earlier Android (&lt;26), the process of <a href="https://developer.android.com/studio/write/java8-support#library-desugaring" rel="nofollow noreferrer">API desugaring</a> brings a <a href="https://developer.android.com/studio/write/java8-support-table" rel="nofollow noreferrer">subset of the java.time</a> functionality not originally built into Android.
<ul>
<li>If the desugaring does not offer what you need, the <a href="https://github.com/JakeWharton/ThreeTenABP" rel="nofollow noreferrer">ThreeTenABP</a> project adapts <a href="http://www.threeten.org/threetenbp/" rel="nofollow noreferrer">ThreeTen-Backport</a> (mentioned above) to Android. See <a href="http://stackoverflow.com/q/38922754/642706">How to use ThreeTenABP…</a>.</li>
</ul>
</li>
</ul>
</li>
</ul>

blocks|key|2982426|text|使用timezone分析时间，模式中的Z用于时区|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|2982427|String+aTime+=+"2017-10-25T11:39:00%2B09:00";
SimpleDateFormat+sdf+=+new+SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ",+Locale.getDefault());
try+{
++++Calendar+cal+=+Calendar.getInstance();
++++cal.setTime(sdf.parse(aTime));
++++Log.i(TAG,+"time+=+"+%2B+cal.getTimeInMillis());+
}+catch+(ParseException+e)+{
++++e.printStackTrace();
}|code-block|syntax|javascript|2982428|输出:它将返回UTC时间|2982429|1508899140000|2982430|​|2982431|📷|atomic|2982432|2982433|如果我们不像yyyy-MM-dd'T'HH:mm:ss那样设置时区。SimpleDateFormat将使用在Setting中设置的时区|2982434|entityMap|0|IMAGE|mutability|IMMUTABLE|imageUrl|https://ask.qcloudimg.com/http-save/yehe-900000/a27b1e0a23d6598f68599876cf449b36.png|imageAlt^0|J|1|0|0|0|0|0|0|1|0|0|0|6|L|Y|G|1I|7|0^^$0|@$1|2|3|4|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|18|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|19|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|1A|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|1B|8|@]|D|@]|E|$]]|$1|Q|3|R|5|S|7|1C|8|@]|D|@$9|1D|A|1E|1|1F]]|E|$]]|$1|T|3|P|5|6|7|1G|8|@]|D|@]|E|$]]|$1|U|3|V|5|6|7|1H|8|@$9|1I|A|1J|B|C]|$9|1K|A|1L|B|C]|$9|1M|A|1N|B|C]]|D|@]|E|$]]|$1|W|3|-4|5|6|7|1O|8|@]|D|@]|E|$]]]|X|$Y|$5|Z|10|11|E|$12|13|14|-4]]]]

Parse a time with timezone, <code>Z</code> in pattern is for time zone

<pre><code>String aTime = "2017-10-25T11:39:00+09:00";
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssZ", Locale.getDefault());
try {
 Calendar cal = Calendar.getInstance();
 cal.setTime(sdf.parse(aTime));
 Log.i(TAG, "time = " + cal.getTimeInMillis()); 
} catch (ParseException e) {
 e.printStackTrace();
}
</code></pre>

Output: it will return the UTC time

<pre><code>1508899140000
</code></pre>

<a href="https://i.stack.imgur.com/jjNOi.png" rel="noreferrer"><img src="https://i.stack.imgur.com/jjNOi.png" alt="enter image description here"></a>

If we don't set the time zone in pattern like <code>yyyy-MM-dd'T'HH:mm:ss</code>. <code>SimpleDateFormat</code> will use the time zone which have set in <code>Setting</code>

I am new to Java, usually work with PHP.

I am trying to convert this string:

<blockquote>
 Mon Mar 14 16:02:37 GMT 2011
</blockquote>

Into a Calendar Object so that I can easily pull the Year and Month like this:

<pre><code>String yearAndMonth = cal.get(Calendar.YEAR)+cal.get(Calendar.MONTH);
</code></pre>

Would it be a bad idea to parse it manually? Using a substring method?

Any advice would help thanks!

Convert String to Calendar Object in Java

我是Java新手，通常使用PHP。我正在尝试转换这个字符串： Mon Mar 14 16:02:37 GMT 2011放到一个Calendar对象中，这样我就可以像这样轻松地提取年份和月份：String yearAndMonth = cal.get(Calendar.YEAR)+cal.get(Calendar.MON...

问在Java中将字符串转换为Calendar对象
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