拉尔森函数，用于根据日期计算星期几

现在的函数输入字符串的格式是：yyyy-MM-dd

例如：2011-01-22

输出是字符串：星期六

?

/**
??? ?* James larsson method.Caculate week from date.
??? ?* @param date fromat:yyyy-MM-dd
??? ?* @return
??? ?*/
??? private String CaculateWeekDay(String date)
??? {
??? ???
??? ??? String dateYear = date.substring(0, 4);
??? ??? String dateMonth = date.substring(5, 7);
??? ??? String dateDay = date.substring(8, 10);
??? ??? int y = Integer.parseInt(dateYear);
??? ??? int m = Integer.parseInt(dateMonth);
??? ??? int d = Integer.parseInt(dateDay);
??? ???
??? ??? if(m==1||m==2) {
??? ??????? m+=12;
??? ??????? y--;
??? ??? }
??? ??? int iWeek=(d+2*m+3*(m+1)/5+y+y/4-y/100+y/400)%7;
??? ??? switch(iWeek)
??? ??? {
??? ??? case 0:
??? ??????? return this.getString(“周一”);
??? ??? case 1:
??? ??????? return this.getString(“周二”);
??? ??? case 2:
??? ??????? return this.getString(“周三”);
??? ??? case 3:
??? ??????? return this.getString(“周四”);
??? ??? case 4:
??? ??????? return this.getString(“周五”);
??? ??? case 5:
??? ??????? return this.getString(“周六”);
??? ??? case 6:
??? ??????? return this.getString(“周日”);
??? ??? }
??? ??? return "";
??? }