SimpleDateFormat 行为

Question

我有以下几行：

final SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd");
Date d = simpleDateFormat.parse("2004-52-05");

我预计第 2 行会抛出异常，因为 '52' 不是有效月份，但代码运行并且 d 对象中存储的日期是

Sat Apr 05 00:00:00 EEST 2008

有人可以解释一下为什么吗？

Answer 1

If you want to create a date object that strictly matches your pattern, then set lenient to false.

来自 Javadoc

Calendar has two modes for interpreting the calendar fields, lenient and non-lenient. When a Calendar is in lenient mode, it accepts a wider range of calendar field values than it produces. When a Calendar recomputes calendar field values for return by get(), all of the calendar fields are normalized. For example, a lenient GregorianCalendar interprets MONTH == JANUARY, DAY_OF_MONTH == 32 as February 1.

请参阅此以获取更多信息lenitent

所以添加这个..

simpleDateFormat.setLenient(false);

这将像您期望的那样抛出 Exception..

java.text.ParseException: Unparseable date: "2004-52-05"

SimpleDateFormat 行为

SimpleDateFormat behaviour

java

simpledateformat