例如,我有日期:“23/2/2010”(2010年2月23日)。我想把它传递给一个返回星期几的函数。我该怎么做呢?

在这个例子中,函数应该返回String "Tue"。

此外,如果只需要日期顺序,如何检索?


当前回答

添加了另一种完全符合OP要求的方法,而不使用最新的内置方法:

public static String getDay(String inputDate) {
    String dayOfWeek = null;
    String[] days = new String[]{"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};

    try {
        SimpleDateFormat format1 = new SimpleDateFormat("dd/MM/yyyy");
        Date dt1 = format1.parse(inputDate);
        dayOfWeek = days[dt1.getDay() - 1];
    } catch(Exception e) {
        System.out.println(e);
    }

    return dayOfWeek;
}

其他回答

  String inputDate = "01/08/2012";
  SimpleDateFormat format1 = new SimpleDateFormat("dd/MM/yyyy");
  Date dt1 = format1.parse(input_date);
  DateFormat format2 = new SimpleDateFormat("EEEE"); 
  String finalDay = format2.format(dt1);

使用此代码从输入日期中查找日期名称。简单且经过良好测试。

对于Java 8或更高版本,Localdate更可取

import java.time.LocalDate;

public static String findDay(int month, int day, int year) {

    LocalDate localDate = LocalDate.of(year, month, day);

    java.time.DayOfWeek dayOfWeek = localDate.getDayOfWeek();
    System.out.println(dayOfWeek);

    return dayOfWeek.toString();
}

注意:如果输入是字符串/用户定义的,那么你应该把它解析成int。

日历类有内置的displayName功能:

Calendar.getInstance().getDisplayName(Calendar.DAY_OF_WEEK, Calendar.SHORT, Locale.getDefault()); // Thu   

Calendar.SHORT -> Thu
Calendar.LONG_FORMAT -> Thursday

Java 1.6以来可用。参见Oracle文档

private String getDay(Date date){

    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("EEEE");
    //System.out.println("DAY "+simpleDateFormat.format(date).toUpperCase());                       
    return simpleDateFormat.format(date).toUpperCase();
}

private String getDay(String dateStr){
    //dateStr must be in DD-MM-YYYY Formate
    Date date = null;
    String day=null;

    try {
        date = new SimpleDateFormat("DD-MM-YYYY").parse(dateStr);

        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("EEEE");
        //System.out.println("DAY "+simpleDateFormat.format(date).toUpperCase());
        day = simpleDateFormat.format(date).toUpperCase();


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


    return day;
}

是的。根据具体情况:

You can use java.util.Calendar: Calendar c = Calendar.getInstance(); c.setTime(yourDate); int dayOfWeek = c.get(Calendar.DAY_OF_WEEK); if you need the output to be Tue rather than 3 (Days of week are indexed starting at 1 for Sunday, see Calendar.SUNDAY), instead of going through a calendar, just reformat the string: new SimpleDateFormat("EE").format(date) (EE meaning "day of week, short version") if you have your input as string, rather than Date, you should use SimpleDateFormat to parse it: new SimpleDateFormat("dd/M/yyyy").parse(dateString) you can use joda-time's DateTime and call dateTime.dayOfWeek() and/or DateTimeFormat. edit: since Java 8 you can now use java.time package instead of joda-time