为什么我在Java中的XPath表达式会返回太多孩子？

I have the following xml file:

我有以下xml文件:

<?xml version="1.0" encoding="UTF-8" standalone="no" ?>
<config>
 <a>
  <b>
   <param>p1</param> 
   <param>p2</param> 
  </b>
 </a>
</config>
<