xml 实例

野性酷女 2022-08-19 13:28 173阅读 0赞

关于节点的**getNodeName()**和**getNodeValue()**方法能得到什么值，可以查看Node类的官方文档：

[http://docs.oracle.com/javase/7/docs/api/org/w3c/dom/Node.html][http_docs.oracle.com_javase_7_docs_api_org_w3c_dom_Node.html]

The values of `nodeName`, `nodeValue`, and `attributes` vary according to the node type as follows:

<table style="border:1px solid silver; border-collapse:collapse; word-break:break-word; color:rgb(0,0,0); font-family:Verdana,Arial,Helvetica,sans-serif; font-size:14px; line-height:25.2000007629395px; width:961px"> 
 <tbody> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> Interface </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> nodeName </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> nodeValue </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> attributes </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>Attr</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> same as&nbsp;<code>Attr.name</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> same as&nbsp;<code>Attr.value</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>CDATASection</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>"#cdata-section"</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> same as&nbsp;<code>CharacterData.data</code>, the content of the CDATA Section </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>Comment</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>"#comment"</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> same as&nbsp;<code>CharacterData.data</code>, the content of the comment </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>Document</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>"#document"</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>DocumentFragment</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>"#document-fragment"</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>DocumentType</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> same as&nbsp;<code>DocumentType.name</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>Element</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> same as&nbsp;<code>Element.tagName</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>NamedNodeMap</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>Entity</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> entity name </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>EntityReference</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> name of entity referenced </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>Notation</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> notation name </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>ProcessingInstruction</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> same as&nbsp;<code>ProcessingInstruction.target</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> same as&nbsp;<code>ProcessingInstruction.data</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 <tr> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>Text</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>"#text"</code> </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> same as&nbsp;<code>CharacterData.data</code>, the content of the text node </td> 
 <td style="font-size:14px; border:1px solid silver; border-collapse:collapse; padding:3px"> <code>null</code> </td> 
 </tr> 
 </tbody> 
</table>

See also the [Document Object Model (DOM) Level 3 Core Specification][Document Object Model _DOM_ Level 3 Core Specification].

## 例子程序 ##

首先是XML文档如下：

![复制代码][copycode.gif]

<?xml version="1.0" encoding="UTF-8"?>
 <学生名册 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="C:\Course30\student.xsd">
 <学生 学号="1">
 <姓名>张三</姓名>
 <性别>男</性别>
 <年龄>20</年龄>
 </学生>
 <学生 学号="2">
 <姓名>李四</姓名>
 <性别>女</性别>
 <年龄>19</年龄>
 </学生>
 <学生 学号="3">
 <姓名>王五</姓名>
 <性别>男</性别>
 <年龄>21</年龄>
 </学生>
 </学生名册>

![复制代码][copycode.gif]

然后是Java程序：

![复制代码][copycode.gif]

package com.learnjava.xml.dom;
 
 import java.io.File;
 
 import javax.xml.parsers.DocumentBuilder;
 import javax.xml.parsers.DocumentBuilderFactory;
 
 import org.w3c.dom.Document;
 import org.w3c.dom.Element;
 import org.w3c.dom.NamedNodeMap;
 import org.w3c.dom.Node;
 import org.w3c.dom.NodeList;
 
 public class DomTest2
 {
 public static void main(String[] args) throws Exception
 {
 DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
 
 DocumentBuilder db = dbf.newDocumentBuilder();
 
 Document doc = db.parse(new File("student.xml"));
 
 // System.out.println(doc.getXmlEncoding());
 // System.out.println(doc.getXmlVersion());
 // System.out.println(doc.getXmlStandalone());
 
 // 得到根节点
 Element root = doc.getDocumentElement();
 System.out.println("rootTagName: " + root.getTagName());
 
 // 得到根节点的子节点，注意此处的空格也被计为子节点
 NodeList list = root.getChildNodes();
 System.out.println("root child Count: " + list.getLength());
 
 for (int i = 0; i < list.getLength(); i++)
 {
 System.out.println("item " + i + ": getNodeName: "
 + list.item(i).getNodeName());
 }
 
 System.out.println("------------NodeType and Value----------------");
 
 for (int i = 0; i < list.getLength(); i++)
 {
 Node n = list.item(i);
 
 // getNodeType返回的是short型的常量值，文档中有定义每个值对应的类型
 System.out.println("getNodeType: " + n.getNodeType()
 + " , getNodeValue: " + n.getNodeValue());
 }
 
 System.out.println("-----------getTextContent----------------");
 
 for (int i = 0; i < list.getLength(); i++)
 {
 Node n = list.item(i);
 
 System.out.println(n.getTextContent());
 }
 
 System.out.println("-------------属性测试----------------");
 
 NodeList nodeList = doc.getElementsByTagName("学生");
 
 for (int i = 0; i < nodeList.getLength(); i++)
 {
 NamedNodeMap nnm = nodeList.item(i).getAttributes();
 
 String attrName = nnm.item(0).getNodeName();
 System.out.print("node " + i + ": " + attrName);
 System.out.print("=");
 
 // 属性的名字和值即为本身的名字和值
 String attrValue = nnm.item(0).getNodeValue();
 System.out.println(attrValue);
 }
 
 }
 }

![复制代码][copycode.gif]

程序输出：

![复制代码][copycode.gif]

rootTagName: 学生名册
    root child Count: 7
    item 0: getNodeName: #text
    item 1: getNodeName: 学生
    item 2: getNodeName: #text
    item 3: getNodeName: 学生
    item 4: getNodeName: #text
    item 5: getNodeName: 学生
    item 6: getNodeName: #text
    ------------NodeType and Value----------------
    getNodeType: 3 , getNodeValue: 
        
    getNodeType: 1 , getNodeValue: null
    getNodeType: 3 , getNodeValue: 
        
    getNodeType: 1 , getNodeValue: null
    getNodeType: 3 , getNodeValue: 
        
    getNodeType: 1 , getNodeValue: null
    getNodeType: 3 , getNodeValue: 
    
    -----------getTextContent----------------
    
        
    
            张三
            男
            20
        
    
        
    
            李四
            女
            19
        
    
        
    
            王五
            男
            21
        
    
    
    -------------属性测试----------------
    node 0: 学号=1
    node 1: 学号=2
    node 2: 学号=3

![复制代码][copycode.gif]

## 参考资料 ##

圣思园张龙老师视频教程。

Java官方文档：[http://docs.oracle.com/javase/7/docs/api/index.html][http_docs.oracle.com_javase_7_docs_api_index.html]

[http_docs.oracle.com_javase_7_docs_api_org_w3c_dom_Node.html]: http://docs.oracle.com/javase/7/docs/api/org/w3c/dom/Node.html
[Document Object Model _DOM_ Level 3 Core Specification]: http://www.w3.org/TR/2004/REC-DOM-Level-3-Core-20040407
[copycode.gif]: /images/20220731/f161d1bb9361400d9be60c3482edc7a4.png
[http_docs.oracle.com_javase_7_docs_api_index.html]: http://docs.oracle.com/javase/7/docs/api/index.html