java - LocalDate - 解析区分大小写

Question

public class Solution {

    public static void main(String[] args) {
        System.out.println(isDateOdd("MAY 1 2013"));
    }

    public static boolean isDateOdd(String date) {

        DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM dd yyyy");
        formatter = formatter.withLocale(Locale.ENGLISH); 
        LocalDate outputDate = LocalDate.parse(date, formatter);
        return ((outputDate.getDayOfYear()%2!=0)?true:false);
    }
}

我想知道从年初到某个日期的天数是否为奇数。我尝试使用 LocalDate 从我的字符串 (MAY 1 2013) 中解析日期，但出现错误:

Exception in thread "main" java.time.format.DateTimeParseException: Text 'MAY 1 2013' could not be parsed at index 0 at java.time.format.DateTimeFormatter.parseResolved0(DateTimeFormatter.java:1949) at java.time.format.DateTimeFormatter.parse(DateTimeFormatter.java:1851) at java.time.LocalDate.parse(LocalDate.java:400) at com.javarush.task.task08.task0827.Solution.isDateOdd(Solution.java:23) at com.javarush.task.task08.task0827.Solution.main(Solution.java:16)

哪里出了问题？

Answer 1

如果你想使用所有大写字母的月份输入，例如 MAY，你必须使用不区分大小写的 DateTimeFormatter:

public static boolean isDateOdd(String date) {
    DateTimeFormatter formatter = new DateTimeFormatterBuilder()
            .parseCaseInsensitive()
            .appendPattern("MMM d yyyy")
            .toFormatter(Locale.ENGLISH);
    LocalDate outputDate = LocalDate.parse(date, formatter);
    return (outputDate.getDayOfYear() % 2 != 0);
}

作为documentation parseCaseSensitive() 方法说:

Since the default is case sensitive, this method should only be used after a previous call to #parseCaseInsensitive.