XML解析方法DOM（Java）

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XML的解析通常有DOM和SAX两种方式，JDK对这两种方式都提供了支持，相关API分布在 java.xml   org.w3c.dom   org.xml.sax包及其子包下面。

DOM方式对XML文件进行解析

 XML ＤＯＭ　和 JavaScript DOM非常相似，主要解析步骤

1 得到document对象

DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
String path = DOMTest.class.getResource("/users.xml").getFile();
Document document = documentBuilder.parse(path);

2 获取要操作的元素

NodeList userNodeList = document.getElementsByTagName("user");
Element userElement = document.getElementById("u001");

3 进一步获得元素的内容（属性 文本内容  子元素）

String name = userElement.getAttribute("name");
String email = emailElement.getTextContent();
NodeList emailNodeList = userElement.getElementsByTagName("email");

实际例子：

XML文件内容

<?xml version="1.0" encoding="UTF-8"?>
<students>
	<student id="s1" name="tom">
		<email>[email protected]</email>
		<phone>12333333333</phone>
	</student>
	<student id="s2" name="lucy">
		<email>[email protected]</email>
		<phone>12333333333</phone>
	</student>
</students>

解析代码：

import java.util.ArrayList;
import java.util.List;

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

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

public class dom_test {

	public static void main(String[] args) throws Exception {
		//得到document对象
		DocumentBuilderFactory documentBuilderFactory=DocumentBuilderFactory.newInstance();
		DocumentBuilder documentBuilder=documentBuilderFactory.newDocumentBuilder();
		String path=dom_test.class.getResource("Students.xml").getFile();
		Document document=documentBuilder.parse(path);
		
		List<Student> list=new ArrayList<Student>();
		//获得想要操作的元素
		NodeList nodeList=document.getElementsByTagName("student");
		
		for (int i = 0; i < nodeList.getLength(); i++) {
			Element stuElement=(Element)nodeList.item(i);
			Student stu=new Student();
			//获取属性值
			String id=stuElement.getAttribute("id");
			String name=stuElement.getAttribute("name");

			stu.setId(id);
			stu.setName(name);
			//获取子元素
			NodeList emailNodeList=stuElement.getElementsByTagName("email");
			for (int j = 0; j < emailNodeList.getLength(); j++) {
				Element emailElement=(Element)emailNodeList.item(j);
				String email=emailElement.getTextContent();
				stu.setEmail(email);
			}
			NodeList phoneNodeList=stuElement.getElementsByTagName("phone");
			for (int j = 0; j < phoneNodeList.getLength(); j++) {
				Element phoneElement=(Element)phoneNodeList.item(j);
				String phone=phoneElement.getTextContent();
				stu.setPhone(phone);
			}

			System.out.println(stu);
		}
		System.out.println(list);
			
	}
}