Java Calendar.WEEK OF YEAR不'；我不能正常工作

Calendar.WEEK OF YEAR无法正常工作。我的目标是每周一都是新的一周。我得到的结果在代码注释中

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我的代码是：

Calendar cal = Calendar.getInstance();
//cal.setMinimalDaysInFirstWeek(7);
//cal.setFirstDayOfWeek(0);
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");

Date d = sdf.parse("27/12/2014"); //SAT
Date d1 = sdf.parse("28/12/2014"); //SUN

cal.setTime(d);
Integer weekNumber1 = cal.get(Calendar.WEEK_OF_YEAR);

cal.setTime(d1);
Integer weekNumber2 = cal.get(Calendar.WEEK_OF_YEAR);

System.out.println( weekNumber1 );// 52 
System.out.println( weekNumber2 );// 1`

第二条：

Calendar cal = Calendar.getInstance();
cal.setMinimalDaysInFirstWeek(7);
//cal.setFirstDayOfWeek(0);
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");

Date d = sdf.parse("27/12/2014"); //SAT
Date d1 = sdf.parse("28/12/2014"); //SUN

cal.setTime(d);
Integer weekNumber1 = cal.get(Calendar.WEEK_OF_YEAR);

cal.setTime(d1);
Integer weekNumber2 = cal.get(Calendar.WEEK_OF_YEAR);

System.out.println( weekNumber1 );// 51 
System.out.println( weekNumber2 );// 52

第三点：

Calendar cal = Calendar.getInstance();
cal.setMinimalDaysInFirstWeek(7);
cal.setFirstDayOfWeek(0);
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");

Date d = sdf.parse("27/12/2014"); //SAT
Date d1 = sdf.parse("28/12/2014"); //SUN
Date d2 = sdf.parse("29/12/2014"); //Mon

cal.setTime(d);
Integer weekNumber1 = cal.get(Calendar.WEEK_OF_YEAR);

cal.setTime(d1);
Integer weekNumber2 = cal.get(Calendar.WEEK_OF_YEAR);

cal.setTime(d2);
Integer weekNumber3 = cal.get(Calendar.WEEK_OF_YEAR);

System.out.println( weekNumber1 );// 52
System.out.println( weekNumber2 );// 52
System.out.println( weekNumber3 );// 52

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您必须将星期一设置为日历的每周第一天

cal.setFirstDayOfWeek(Calendar.MONDAY);

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日期d2=sdf.parse（“2014年12月28日”）//Mon是错的Monday是29/12问题被编辑了，但输出并没有改变29返回52o是的，我想cal.setFirstDayOfWeek（0）；（在我看来，mondey）也是一样。秋明大学