Java-优化java获取当前系统时间属于第几周(时间段)?

Question

代码如下：

public static void getDayOfWeek() {
        String conMonth = "1" ; //当前的月份
        
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Calendar c = Calendar.getInstance();
        int year = c.get(Calendar.YEAR);
        long l = c.getTime().getTime();

        int currentWeekOfYear = c.get(Calendar.WEEK_OF_YEAR);
        if (currentWeekOfYear == 1 && c.get(Calendar.MONTH) == 11) {
            currentWeekOfYear = 53;
        }

        int j = 12;
        for (int i=0; i < currentWeekOfYear; i++) {
            int dayOfWeek = c.get(Calendar.DAY_OF_WEEK) - 2;
            c.add(Calendar.DATE, - dayOfWeek); //得到本周的第一天
            String month = (c.get(Calendar.MONTH) + 1) + "";  //得到月份
            
            String date = sdf.format(c.getTime());
            c.add(Calendar.DATE, 6);  //得到本周的最后一天
            
            long ll = c.getTime().getTime();
            String date2 = sdf.format(c.getTime());
            c.add(Calendar.DATE, -j); //减去增加的日期
            if(month.equals(conMonth)) {
               if (l > ll) {
                    String s = year + "年的第" + (currentWeekOfYear - i) + "周" + "(" + date + "至" + date2 + ")"; 
                    System.out.println(s);
               }
            }
        }
}

Answer 1

算星期几,没有这么麻烦吧...只是long值运算而已.找一个你已经知道的日期,作为时间参照点.比如今天0点0分0秒是星期几.然后把两个时间点的时间戳做差值,再求7天的余数.最后简单加减不就知道是星期几了吗?