日期时间（二）

 

　　 // Calendar.class
    // 如果直接设置月份或者星期时请注意±1，使用SimpleDateFormat则无此问题。
    /*
     * #DAY_OF_WEEK 
     * public final static int SUNDAY = 1; 
     * public final static int MONDAY = 2; 
     * public final static int TUESDAY = 3; 
     * public final static int WEDNESDAY = 4; 
     * public final static int THURSDAY = 5; 
     * public final static int FRIDAY = 6; 
     * public final static int SATURDAY = 7;
     * 
     * #MONTH public
     * final static int JANUARY = 0; 
     * public final static int FEBRUARY = 1;
     * public final static int MARCH = 2; 
     * public final static int APRIL = 3;
     * public final static int MAY = 4; 
     * public final static int JUNE = 5; 
     * public final static int JULY = 6; 
     * public final static int AUGUST = 7; 
     * public final static int SEPTEMBER = 8; 
     * public final static int OCTOBER = 9;
     * public final static int NOVEMBER = 10; 
     * public final static int DECEMBER = 11; 
     * public final static int UNDECIMBER = 12;
     */

 Map<String, Integer> java.util.Calendar.getDisplayNames(int field, int style, Locale locale)

field 可以显示的有：几月，星期几

style 可能的样式：缩写，全拼，全部

localse 所有可能的时区

public static void main(String[] args) {
        Calendar c = Calendar.getInstance();
        System.out.println(c.getDisplayNames(Calendar.DAY_OF_WEEK, Calendar.LONG, Locale.UK));
        System.out.println(c.getDisplayNames(Calendar.DAY_OF_WEEK, Calendar.SHORT, Locale.UK));
        System.out.println(c.getDisplayNames(Calendar.DAY_OF_WEEK, Calendar.ALL_STYLES, Locale.UK));

        System.out.println(c.getDisplayName(Calendar.DAY_OF_WEEK, Calendar.LONG, Locale.UK));

        System.out.println(c.getDisplayNames(Calendar.MONTH, Calendar.LONG, Locale.UK));
        System.out.println(c.getDisplayName(Calendar.MONTH, Calendar.LONG, Locale.UK));
    }

结果：

{Saturday=7, Thursday=5, Monday=2, Tuesday=3, Wednesday=4, Friday=6, Sunday=1}
{Thu=5, Wed=4, Sun=1, Sat=7, Fri=6, Tue=3, Mon=2}
{Thu=5, Thursday=5, Saturday=7, Monday=2, Wed=4, Sun=1, Tuesday=3, Sat=7, Wednesday=4, Fri=6, Tue=3, Mon=2, Friday=6, Sunday=1}
Wednesday
{October=9, January=0, April=3, February=1, August=7, June=5, November=10, July=6, May=4, December=11, March=2, September=8}
June

 

常见操作

1) 获取上一个5分整时间段

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm");
        String format = sdf.format(new Date());
        Date now = sdf.parse(format);
        Integer curMin = Integer.valueOf(format.split(":")[1]);
        Date stime = null;
        Date etime = null;
        if(curMin%5 == 0) {
            stime = new Date(now.getTime() - 5 * 60 * 1000);
            etime = now;
        }else {
            int i=0;
            for(;curMin%5 != 0;curMin--) {
                i++;
            }
            stime = new Date(now.getTime() - (i+5) * 60 * 1000);
            etime = new Date(now.getTime() - (i+0) * 60 * 1000);
        }
        SimpleDateFormat sdf2 = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        System.out.println(sdf2.format(stime));
        System.out.println(sdf2.format(etime));

 

 

    public static Date[] getThisWeek(boolean tillToday) {
        int len = 7;
        if (tillToday) {
            len = Calendar.getInstance().get(Calendar.DAY_OF_WEEK) - 1;
        }
        Date[] result = new Date[len];
        for (int i = 0; i < len; i++) {
            Calendar c = Calendar.getInstance();
            c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
            c.add(Calendar.DATE, i);
            result[i] = c.getTime();
        }
        return result;
    }
    
    public static Date[] getLastWeek() {
        Date[] result = new Date[7];
        for (int i = 0; i < 7; i++) {
            Calendar c = Calendar.getInstance();
            c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
            c.add(Calendar.DATE, i-7);
            result[i] = c.getTime();
        }
        return result;
    }
    
    public static Date[] getThisMonth(boolean tillToday) {
        Calendar now = Calendar.getInstance();
        int len = now.getActualMaximum(Calendar.DAY_OF_MONTH);
        if (tillToday) {
            len = now.get(Calendar.DAY_OF_MONTH);
        }
        Date[] result = new Date[len];
        for (int i = 0; i < len; i++) {
            Calendar c = Calendar.getInstance();
            c.set(Calendar.DAY_OF_MONTH, 1);
            c.add(Calendar.DATE, i);
            result[i] = c.getTime();
        }
        return result;
    }
    
    public static Date[] getLastMonth() {
        Calendar now = Calendar.getInstance();
        now.set(Calendar.MONTH, now.get(Calendar.MONTH) - 1);
        int len = now.getActualMaximum(Calendar.DAY_OF_MONTH);
        Date[] result = new Date[len];
        for (int i = 0; i < len; i++) {
            Calendar c = Calendar.getInstance();
            c.set(Calendar.MONTH, c.get(Calendar.MONTH) - 1);
            c.set(Calendar.DAY_OF_MONTH, 1);
            c.add(Calendar.DATE, i);
            result[i] = c.getTime();
        }
        return result;
    }

Tips:

// 当前天所在周，周六
c.set(Calendar.DAY_OF_WEEK, c.getActualMaximum(Calendar.DAY_OF_WEEK));
// 当前天所在周，周一
c.set(Calendar.DAY_OF_WEEK,Calendar.MONDAY);
// 当前天所在周，周日
c.set(Calendar.DAY_OF_WEEK,Calendar.MONDAY);
c.add(Calendar.DATE, 6);

// 当前天所在月，第一天
c.set(Calendar.DAY_OF_MONTH,1);
// 当前天所在月，月末
c.set(Calendar.DAY_OF_MONTH,c.getActualMaximum(Calendar.DAY_OF_MONTH));

// 当前天所在年，第一天
c.set(Calendar.DAY_OF_YEAR,1);
// 当前天所在年，年末
c.set(Calendar.DAY_OF_YEAR,c.getActualMaximum(Calendar.DAY_OF_YEAR));

// 当前天，前一天
c.add(Calendar.DATE, -1);

// 当前天，后一天
c.add(Calendar.DATE, 1);

// 当前天所在月，上一月
c.set(Calendar.MONTH, c.get(Calendar.MONTH) - 1);