读取两个具有相同名称Java的XML标记

Question

我有一个用Java读取的XML文件,如下所示:

<Author AffiliationIDS="Aff1" PresentAffiliationID="Aff2">
    <AuthorName DisplayOrder="Western">
        <GivenName>Kun-Jing</GivenName>
        <FamilyName>Lee</FamilyName>
    </AuthorName>
</Author>
<Author AffiliationIDS="Aff1" PresentAffiliationID="Aff2">
    <AuthorName DisplayOrder="Western">
        <GivenName>John</GivenName>
        <FamilyName>Smith</FamilyName>
    </AuthorName>
</Author>

一开始一切都很好,然后出现这样的事情

<Author AffiliationIDS="Aff1">
    <AuthorName DisplayOrder="Western">
       <GivenName>Z.</GivenName>
       <GivenName>C.</GivenName>
       <FamilyName>Huang</FamilyName>
    </AuthorName>
</Author>
<Author AffiliationIDS="Aff1" PresentAffiliationID="Aff3">
    <AuthorName DisplayOrder="Western">
       <GivenName>J.</GivenName>
       <GivenName>C.</GivenName>
       <FamilyName>Chen</FamilyName>
   </AuthorName>
</Author>

如您所见,<GivenName>标记在同一个块中被提及两次,因此,当我从中调用该值时<GivenName>,仅显示第一个.

这是读取XML文件的Java代码:

package com.mkyong.seo;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.w3c.dom.Node;
import org.w3c.dom.Element;
import java.io.File;

public class ReadXMLFile {

  public static void main(String argv[]) {

        try {

        File fXmlFile = new File("/fileaddress/test-1.xml");
        DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder dBuilder = dbFactory.newDocumentBuilder();
        Document doc = dBuilder.parse(fXmlFile);


        doc.getDocumentElement().normalize();

        System.out.println("Root element :" + doc.getDocumentElement().getNodeName());

        NodeList nList = doc.getElementsByTagName("AuthorName");

        System.out.println("----------------------------");

        for (int temp = 0; temp < nList.getLength(); temp++) {

            Node nNode = nList.item(temp);

            System.out.println("\nCurrent Element :" + nNode.getNodeName());

            if (nNode.getNodeType() == Node.ELEMENT_NODE) {

                Element eElement = (Element) nNode;

                System.out.println("Given Name : " + eElement.getElementsByTagName("GivenName").item(0).getTextContent());
                System.out.println("Family Name : " + eElement.getElementsByTagName("FamilyName").item(0).getTextContent());

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

}

这就是结果:

Root element :AuthorGroup
----------------------------

Current Element :AuthorName
Given Name : Kun-Jing
Family Name : Lee

Current Element :AuthorName
Given Name : John
Family Name : Smith

Current Element :AuthorName
Given Name : Z.
Family Name : Huang

Current Element :AuthorName
Given Name : J.
Family Name : Chen

正如你所看到的,第二个GivenName没有出现,当我尝试向这个添加一个类似的行时,System.out.println("Given Name : " + eElement.getElementsByTagName("GivenName").item(0).getTextContent());它给了我一个NullPointer Exception没有两个给定名称的行.

我该如何阅读这两个<GivenName>标签？

Answer 1

在getElementsByTagName()对方法Element会给你NodeList所提供的标签名称包含匹配的子元素.该文档NodeList位于:http://docs.oracle.com/javase/7/docs/api/org/w3c/dom/NodeList.html.

有关如何迭代GivenName元素的示例:

NodeList giveNames = eElement.getElementsByTagName("GivenName");
for (int i = 0; i < givenNames.getLength(); i++) {
    System.out.println("Given Name : " + givenNames.item(i).getTextContent());
}