java - 如何通过日历获得正确的一年中的周数？

Question

伙计们，我对调用以下方法感到困惑:Calendar.getInstance().get(Calendar.WEEK_OF_YEAR)，从该方法得到的结果不正确。这是我的代码:

    Locale.setDefault(Locale.CHINA);
    Calendar calendar = Calendar.getInstance();
    //we think Monday is the first day of a week in China,but not Sunday.
    calendar.setFirstDayOfWeek(Calendar.MONDAY);
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    String dateString = "2010-01-01";
    calendar.setTime(sdf.parse(dateString));
    System.out.println("DateString: " + dateString + ", week: " + calendar.get(Calendar.WEEK_OF_YEAR));
    dateString = "2010-12-27";
    calendar.setTime(sdf.parse(dateString));
    System.out.println("DateString: " + dateString + ", week: " + calendar.get(Calendar.WEEK_OF_YEAR));

结果是

DateString: 2010-01-01, week: 1//This may be wrong?
DateString: 2010-12-27, week: 1//This result is definitely wrong.

所以问题是，如何使用 Calendar 实例获取正确的一年中的周数？

Answer 1

区域设置仅影响格式(即将日期解析并格式化为中文)。您需要将时区设置为中国。修复 Calendar#getInstance() 行，如下所示:

Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("CST")); // China Standard Time