根据第几周获取当周的开始日期与最后日期

//根据第几周获取当周的开始日期与最后日期    

//$year 年   $week一年中的第几周

private function getWeek($year,$week){ 

  $firstdayofyear=mktime(0,0,0,1,1,$year); 

  $firstweekday=date('N',$firstdayofyear); 

  $firstweenum=date('W',$firstdayofyear); 

  if($firstweenum==1){ 

      $day=(1-($firstweekday-1))+7*($weeknum-1); 

      $startdate=date('Y-m-d',mktime(0,0,0,1,$day,$year)); 

      $enddate=date('Y-m-d',mktime(0,0,0,1,$day+6,$year)); 

  }else{ 

      $day=(9-$firstweekday)+7*($weeknum-1); 

      $startdate=date('Y-m-d',mktime(0,0,0,1,$day,$year)); 

      $enddate=date('Y-m-d',mktime(0,0,0,1,$day+6,$year)); 

  } 

  return array($startdate,$enddate);     

}