怎么计算去年星期相同，日期相近的方法！

Question

Lyweekday s = new Lyweekday("2001-01-15");public int Lyweekday(String Tyweekday)
{
int FD=Integer.parseInt(Tyweekday.substring(0,4))*10000+Integer.parseInt(Tyweekday.substring(5,Tyweekday.lastIndexOf("-")))*100+Integer.parseInt(Tyweekday.substring(Tyweekday.lastIndexOf("-")+1,Tyweekday.length()));
int LFD=FD-10000;
Calendar cal = Calendar.getInstance();

cal.set(Integer.valueOf(Tyweekday.substring(0,4)).intValue(),Integer.valueOf(Tyweekday.substring(5,7)).intValue()-1,Integer.valueOf(Tyweekday.substring(8,10)).intValue());
     int tWek= cal.get(cal.DAY_OF_WEEK);
     int day_29 = 0;
if(Integer.valueOf(Tyweekday.substring(5,7)).intValue()==2&&Integer.valueOf(Tyweekday.substring(8,10)).intValue()==29)
{
day_29=28;
}else
{
day_29=Integer.valueOf(Tyweekday.substring(8,10)).intValue();
}
cal.set(LFD/10000,Integer.valueOf(Tyweekday.substring(5,7)).intValue()-1,day_29);
     cal.add(cal.DATE,1);
     if(cal.get(cal.DAY_OF_WEEK)!=tWek) {cal.add(cal.DATE,1);}
     LFD=cal.get(cal.YEAR)*10000+cal.get(cal.MONTH)*100+cal.get(cal.DATE)+100;

return LFD;
}