Question

我使用简单的日期格式将字符串转换为日期，但是日期的月份总是返回JANUARY，这是我的代码：

  public static void main(String args[]){

    String date = "2017-12-29";
    SimpleDateFormat formatter = new SimpleDateFormat("yyyy-mm-dd");
    SimpleDateFormat dateFormatter = new SimpleDateFormat("MMMM dd, YYYY");
    try {
        Date startEntryDate = formatter.parse(date);
        System.out.println(dateFormatter.format(startEntryDate));

    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

Answer 1

如上所述，您必须使用MM代替mm，但是？
为什么不使用java.time库：

String month = LocalDate.parse("2017-12-29").getMonth().name();

Answer 2

尝试使用

new SimpleDateFormat("yyyy-MM-dd");

mm表示分钟。 MM - 几个月。

Letter   Date or Time Component   Presentation       Examples
G        Era designator             Text                AD
y        Year                       Year                1996;    96
M        Month in year              Month               July; Jul; 07
w        Week in year               Number               27
W        Week in month              Number               2
D        Day in year                Number               189
d        Day in month               Number               10
F        Day of week in month       Number               2
E        Day in week                Text               Tuesday; Tue
a        Am/pm marker               Text               PM
H        Hour in day (0-23)         Number               0
k        Hour in day (1-24)         Number               24
K        Hour in am/pm (0-11)       Number               0
h        Hour in am/pm (1-12)       Number               12
m        Minute in hour             Number               30
s        Second in minute           Number               55
S        Millisecond                Number               978
z        Time zone                  General time zone   Pacific Standard Time; PST; GMT-08:00
Z        Time zone                  RFC 822 time zone   -0800

Answer 3

试试这个：

SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
SimpleDateFormat dateFormatter = new SimpleDateFormat("MMMM dd, yyyy");

Answer 4

   Try this:

        new SimpleDateFormat("MM/dd/yyyy")
        MM is "month" (not mm)
        dd is "day" (not DD)
        It's all in the javadoc for SimpleDateFormat


        FYI, the reason your format is still a valid date format is that:

        mm is "minutes"
        DD is "day in year"
        Also, you don't need the cast to Date... it already is a Date (or it 
        explodes):

            public static void main(String[] args) throws ParseException {
         System.out.println(new 
            SimpleDateFormat("MM/dd/yyyy").parse("08/16/2011"));
            }
        Output:

8月16日星期二00:00:00 EST 2011

Answer 5

试试这个：

    String date = "2017-8-28";
    SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd");
    SimpleDateFormat dateFormatter = new SimpleDateFormat("MMMM dd, YYYY");
    try {
        Date startEntryDate = formatter.parse(date);
        System.out.println(dateFormatter.format(startEntryDate));

    } catch (ParseException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

简单日期格式化程序中的月份始终返回JANUARY

5 个答案: