如何在Java中获取当周第一天的时间戳？

Question

cal.get（）方法是什么意思？

    public static int getTimesWeekmorning(){

    Calendar cal = Calendar.getInstance(); 
    cal.set(cal.get(Calendar.YEAR),cal.get(Calendar.MONDAY), cal.get(Calendar.DAY_OF_MONTH), 0, 0,0);                              
    cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY); 
    return (int) (cal.getTimeInMillis()/1000); 
    }