问题描述
我正在使用 DateFormat 函数将日期转换为这种格式:yyyy-mm-dd.这是日期的原始格式:dd-mm-yyyy.下面是一段代码:
I am using the DateFormat function to convert dates to this format: yyyy-mm-dd. This is the original format of the date: dd-mm-yyyy. Below is a snippet of the code:
<cfset newdate = #DateFormat(Trim(mydate), "yyyy-mm-dd")# />
问题是我在不同的日期得到不同的结果.例如:
The problem is that I get different results for different dates. For example:
- 如果我的原始日期是:
15-05-2013(dd-mm-yyyy) - 结果是:
2013-05-15(yyyy-mm-dd)
- If my original date is:
15-05-2013(dd-mm-yyyy) - The result is:
2013-05-15(yyyy-mm-dd)
但是，如果我更改输入并且:
However, if I change the input and:
- 原日期为:
01-05-2013(dd-mm-yyyy) - 结果是:
2013-01-05(yyyy-dd-mm)
- The original date is:
01-05-2013(dd-mm-yyyy) - The result is:
2013-01-05(yyyy-dd-mm)
我们非常感谢任何有关问题的帮助或指导.
Any help or guidance as to what is wrong would be highly appreciated.
推荐答案
我不同意另一个答案.问题的真正原因是 DateFormat 并非旨在处理非美国日期字符串.
I disagree with the other answer. The real cause of the problem is that DateFormat is not designed to handle non-US date strings.
标准 CF 日期函数总是使用美国日期解析规则.这意味着当您传入一个模棱两可的日期字符串时，例如 01-05-2013，它会根据 美国英文日期约定.在这种情况下，首先是月份，即mm-dd-yyyy".所以结果永远是 1 月 5 日，而不是 5 月 1 日.
The standard CF date functions always use U.S. date parsing rules. That means when you pass in an ambiguous date string, like 01-05-2013, it is parsed according to U.S. English date conventions. In this case, month first ie "mm-dd-yyyy". So the result will always be January 5th, not May 1st.
在某些情况下，您会很幸运.对于字符串 15-05-2013，显然没有第 15 个月，所以 CF/java 必须自动交换月份和日期，而不是抛出错误.这就是为什么 似乎 可以正确处理一些 dd-mm-yyyy 日期字符串，但不能正确处理其他日期字符串.
In some cases you get lucky. With the string 15-05-2013, there is obviously no 15th month, so CF/java must swap the month and day automatically, rather than throwing an error. That is why it seems to handle some dd-mm-yyyy date strings correctly, but not others.
如果要解析非美国日期字符串，则应改用 LS(Locale Sensitive)日期函数.但是，根据文档，破折号即 "-" 在大多数非美国语言环境中不是标准的日期分隔符:只有荷兰语和葡萄牙语(标准).因此，您要么需要更改分隔符，要么在解析日期时使用这两种语言环境之一:
If you want to parse non-US date strings, you should use the LS (Locale Sensitive) date functions instead. However, according to the docs dashes ie "-" are not a standard date separator in most non-US locales: only Dutch and Portuguese (Standard). So you would either need to change the separator OR use one of those two locales when parsing the date:
lsDateFormat( myDate, "yyyy-mm-dd", "pt_PT")
旁注:
顺便说一句，DateFormat 确实需要一个日期对象.然而，像 CF 中的大多数函数一样，它也足够灵活，可以接受日期 string.这使您可以将其用作从日期 string => 日期 object => 然后再次转换回(格式化)日期字符串的惰性快捷方式.最好使用日期对象(你真的应该验证日期字符串)，但这完全是另一个对话......
As an aside, DateFormat does expect a date object. However, like most functions in CF it is flexible enough to accept a date string as well. That allows you to use it as a lazy shortcut to convert from date string => date object => then back to (formatted) date string again. Using date objects is preferable (and you really should validate date strings as well) but that is another conversation altogether ...
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