java日期小工具工具

1. 日期的转换

• 得到某天最大时间 2017-10-15 23:59:59

public static Date getEndOfDay(Date date) {
    
    
        LocalDateTime localDateTime = LocalDateTime.ofInstant(Instant.ofEpochMilli(date.getTime()), ZoneId.systemDefault());;
        LocalDateTime endOfDay = localDateTime.with(LocalTime.MAX);
        return Date.from(endOfDay.atZone(ZoneId.systemDefault()).toInstant());
    }

• 得到某天最小时间 2017-10-15 00:00:00

public static Date getStartOfDay(Date date) {
    
    
        LocalDateTime localDateTime = LocalDateTime.ofInstant(Instant.ofEpochMilli(date.getTime()), ZoneId.systemDefault());
        LocalDateTime startOfDay = localDateTime.with(LocalTime.MIN);
        return Date.from(startOfDay.atZone(ZoneId.systemDefault()).toInstant());
    }

• 根据日期获取对应星期几

public static String getWeekByDate(Date date){
    
    
        String[] weekDays = {
    
     "星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六" };
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        int w = cal.get(Calendar.DAY_OF_WEEK) - 1;
        if (w < 0)
            w = 0;
        return weekDays[w];
}