java计算两数百分比方法

public   static  String percent( double  p1,  double  p2)   
  {
   String str;
   double  p3  =  p1  /  p2;
   NumberFormat nf  = NumberFormat.getPercentInstance();
   nf.setMinimumFractionDigits( 1 );
   str  =  nf.format(p3);
   return  str;
  }