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Create why-is-subtracting-these-two-times-in-1927-giving-a-strange-result.md

这是我翻译的why-is-subtracting-these-two-times-in-1927-giving-a-strange-result这篇问答的中文版。

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	`1`	`+##为什么这两个时间(1927年)相减会得到一个奇怪的结果?`
	`2`	`+`
	`3`	`+###问题描述`
	`4`	`+如果我运行如下的程序,将两个相距一秒的日期解析成字符串并比较他们。`
	`5`	+```
	`6`	`+public static void main(String[] args) throws ParseException {`
	`7`	`+ SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");`
	`8`	`+ String str3 = "1927年12月31日 23:54:07";`
	`9`	`+ String str4 = "1927年12月31日 23:54:08";`
	`10`	`+ Date sDt3 = sf.parse(str3);`
	`11`	`+ Date sDt4 = sf.parse(str4);`
	`12`	`+ long ld3 = sDt3.getTime() /1000;`
	`13`	`+ long ld4 = sDt4.getTime() /1000;`
	`14`	`+ System.out.println(ld4-ld3);`
	`15`	`+}`
	`16`	+```
	`17`	`+`
	`18`	`+输出结果为:`
	`19`	+```
	`20`	`+353`
	`21`	+```
	`22`	`+`
	`23`	+为什么`ld4-ld3`不是`1`(正如我所期望的那样),而是`353`?
	`24`	`+`
	`25`	`+如果我把时间改变为之后的一秒:`
	`26`	+```
	`27`	`+String str3 = "1927年12月31日 23:54:08";`
	`28`	`+String str4 = "1927年12月31日 23:54:09";`
	`29`	+```
	`30`	`+`
	`31`	+这时,`ld4-ld3`的结果为`1`.
	`32`	`+`
	`33`	`+java版本:`
	`34`	+```
	`35`	`+java version "1.6.0_22"`
	`36`	`+Java(TM) SE Runtime Environment (build 1.6.0_22-b04)`
	`37`	`+Dynamic Code Evolution Client VM (build 0.2-b02-internal, 19.0-b04-internal, mixed mode)`
	`38`	+```
	`39`	`+`
	`40`	`+时区:`
	`41`	+```
	`42`	`+sun.util.calendar.ZoneInfo[id="Asia/Shanghai",`
	`43`	`+offset=28800000,dstSavings=0,`
	`44`	`+useDaylight=false,`
	`45`	`+transitions=19,`
	`46`	`+lastRule=null]`
	`47`	`+`
	`48`	`+Locale(Locale.getDefault()): zh_CN`
	`49`	+```
	`50`	`+`
	`51`	`+###问题回答`
	`52`	`+这是因为1927年11月31日上海的时区改变了。`
	`53`	`+观看[此页](http://www.timeanddate.com/time/change/china/shanghai?year=1927)获得更多关于上海1927年的细节。`
	`54`	`+这个问题主要是由于在1927年12月31日的午夜,时钟回调了5分钟零52秒。`
	`55`	`+所以"1927年12月31日 23:54:08"这个时间实际上发生了两次,看上去java将这个时间解析为之后的那个瞬间。`
	`56`	`+因此出现了这种差别。`
	`57`	`+`
	`58`	`+这只是美好但奇怪的世界时区中的一个插曲。`
	`59`	`+`

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