//参数1是类名,参数2是方法名
$func = new ReflectionMethod('UnifiedOrder_pub', 'getPrepayId');
//从第几行开始
$start = $func->getStartLine() - 1;
//从第几行结束
$end = $func->getEndLine() - 1;
//获取路径地址
$filename = $func->getFileName();

<?php
function a() {
}
class b {
  public function f() {
  }
}
function function_dump($funcname) {
  try {
    if(is_array($funcname)) {
      $func = new ReflectionMethod($funcname[0], $funcname[1]);
      $funcname = $funcname[1];
    } else {
      //这个应该是当只有一个参数的时候就看做是本类的发放吧,大概,自行百度
      $func = new ReflectionFunction($funcname);
    }
  } catch (ReflectionException $e) {
    echo $e->getMessage();
    return;
  }
  $start = $func->getStartLine() - 1;
  $end = $func->getEndLine() - 1;
  $filename = $func->getFileName();
  echo "function $funcname defined by $filename($start - $end)\n";
}
function_dump('a');
function_dump(array('b', 'f'));
$b = new b();
function_dump(array($b, 'f'));
?>