为什么我将额外的文本节点作为根节点的子节点？ [英] Why am I getting extra text nodes as child nodes of root node?

问题描述

我想打印根节点的子元素。这是我的XML文件。

I want to print the child elements of the root node. This is my XML file.

<?xml version="1.0"?>
<!-- Hi -->
<company>
   <staff id="1001">
       <firstname>yong</firstname>
       <lastname>mook kim</lastname>
       <nickname>mkyong</nickname>
       < salary>100000</salary>
   </staff>
   <staff id="2001">
       <firstname>low</firstname>
       <lastname>yin fong</lastname>
       <nickname>fong fong</nickname>
       <salary>200000</salary>
   </staff>
</company>

根据我的理解，Root节点是'company'，其子节点必须是'staff'和'员工'（因为有'员工'节点2次）。但是当我试图让他们通过我的java代码时，我得到了5个子节点。 3个额外的文本节点将从哪里来？

According to my understanding, Root node is 'company' and its child nodes must be 'staff' and 'staff' (as there are 'staff' nodes 2 times). But when I am trying to get them through my java code I am getting 5 child nodes. From where are the 3 extra text nodes are coming ?

Java代码：

package com.training.xml;

import java.io.File;


import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;


public class ReadingXML {


public static void main(String[] args) {
    try {

        File file=new File("D:\\TestFile.xml");
        DocumentBuilderFactory     dbFactory=DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder=dbFactory.newDocumentBuilder();
        Document document=dBuilder.parse(file);
        document.getDocumentElement().normalize();
        System.out.println("root element: "+document.getDocumentElement().getNodeName());
        Node rootNode=document.getDocumentElement(); //saving root node in a variable.
        System.out.println("root: "+rootNode.getNodeName());
        NodeList nList=rootNode.getChildNodes(); //to store the child nodes as node list.
        for(int i=0;i<nList.getLength();i++)
        {
            System.out.println("node name: "+nList.item(i).getNodeName() );
        }


    }
    catch(Exception e)
    {
        e.printStackTrace();
    }

}

}

输出：

root element: company
root: company
node name: #text
node name: staff
node name: #text
node name: staff
node name: #text

为什么这三个文本节点都来了？

Why the three text nodes are coming over here ?

推荐答案

为什么这三个文本节点都来到这里？

Why the three text nodes are coming over here ?

它们之间是空格child 元素。如果你只想要子元素，你应该忽略其他类型的节点：

They're the whitespace between the child elements. If you only want the child elements, you should just ignore nodes of other types:

for (int i = 0;i < nList.getLength(); i++) {
    Node node = nList.item(i);
    if (node.getNodeType() == Node.ELEMENT_NODE) {
        System.out.println("node name: " + node.getNodeName());
    }
}

或者您可以将文档更改为没有该空格。

Or you could change your document to not have that whitespace.

或者您可以使用不同的XML API，它可以让您轻松地询问元素。 （DOM API在各方面都很痛苦。）

Or you could use a different XML API which allows you to easily ask for just elements. (The DOM API is a pain in various ways.)

如果你只想忽略元素内容空格，你可以使用 Text.isElementContentWhitespace 。

If you only want to ignore element content whitespace, you can use Text.isElementContentWhitespace.

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