java XML解析之XPath解析

最新推荐文章于 2025-05-28 16:05:02 发布

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最新推荐文章于 2025-05-28 16:05:02 发布

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分类专栏： java学习笔记文章标签： xml XPath 解析

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本文介绍了一种使用Java实现XML文件解析的方法，并通过XPath选取指定节点。具体步骤包括实例化DocumentBuilderFactory与XPath对象，解析XML文件，获取所需节点数据，并将数据存储到自定义Java类中。

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1.实例化DocumentBuilderFactory对象，该对象帮助创建DocumentBuilder对象，用于解析。

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();//实例化DocumentBuilderFactory对象
DocumentBuilder bulider = dbf.newDocumentBuilder();

2.用DocumentBuilder对象进行解析

Document doc= bulider.parse(Thread.currentThread().getContextClassLoader().getResourceAsStream("MyXML/Student.xml"));

3.实例化Xpath对象

PathFactory factory = XPathFactory.newInstance();//实例化XPathFactory对象，帮助创建XPath对象

XPath xpath = factory.newXPath();

4.获取XML文件的节点，进行操作

XPathExpression compile = xpath.compile("//student");//选取student节点

NodeList nodes = (NodeList)compile.evaluate(doc, XPathConstants.NODESET);//获取student节点的所有节点

例子

1.创建XML文件

<?xml version="1.0" encoding="UTF-8"?>
<students>
	<student score="23">
		<name>"张三"</name>
		<sex>女</sex>
		<id>1003</id>
	</student>
	
	<student score="24">
		<name>"李四"</name>
		<sex>男</sex>
		<id>1004</id>
	</student>
	
	<student id="1005">
		<name>"张五"</name>
		<sex>男</sex>
		<score>25</score>	
	</student>

</students>

2.创建Students类，将解析的数据存储来该类的对象

package MyXMl;

public class Students {
	private int id;
	private int socre;
	private String name;
	private String sex;
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public int getSocre() {
		return socre;
	}
	public void setSocre(int socre) {
		this.socre = socre;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getSex() {
		return sex;
	}
	public void setSex(String sex) {
		this.sex = sex;
	}
	@Override
	public String toString() {
		return "Students [id=" + id + ", socre=" + socre + ", name=" + name + ", sex=" + sex + "]";
	}	
}

3.主类进行解析测试：

package MyXMl;

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

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.xpath.XPath;
import javax.xml.xpath.XPathConstants;
import javax.xml.xpath.XPathExpression;
import javax.xml.xpath.XPathFactory;

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

public class XPathParse {
	public static void main(String[] args) throws Exception{
		List <Students>list = new ArrayList<Students>();//解析出来的数据用Stundent对象存储，用集合存储该对象
		
		DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();//实例化DocumentBuilderFactory对象
		DocumentBuilder bulider = dbf.newDocumentBuilder();
		Document doc = bulider.parse(Thread.currentThread().getContextClassLoader().getResourceAsStream("MyXML/Student.xml"));
		
		XPathFactory factory = XPathFactory.newInstance();//实例化XPathFactory对象
		XPath xpath = factory.newXPath();
		
		XPathExpression compile = xpath.compile("//student");//选取student节点
		NodeList nodes = (NodeList)compile.evaluate(doc, XPathConstants.NODESET);//获取student节点的所有节点
		for(int i=0;i<nodes.getLength();i++) {
			Students stu = new Students();
	          NodeList childNodes = nodes.item(i).getChildNodes(); //获取一个student节点所有的子节点，返回集合
	         //遍历所有子节点，获取节点的名称与数据，将其存与Students对象的属性进行匹配并存入到该对象
	          for(int j=0;j<childNodes.getLength();j++) {
	        	 Node node = childNodes.item(j);
	        	 if("name".equals(node.getNodeName())) {
	        		 stu.setName(node.getTextContent());
	        	 }
	        	 if("sex".equals(node.getNodeName())) {
	        		 stu.setSex(node.getTextContent());
	        	 }
	        	 if("id".equals(node.getNodeName())) {
	        		 stu.setId(Integer.parseInt(node.getTextContent()));
	        	 }
	        	 if("score".equals(node.getNodeName())) {
	        		 stu.setSocre(Integer.parseInt(node.getTextContent()));
	        	 }
	          }
	          //获取 student节点的属性，将其存与Students对象的属性进行匹配并存入到该对象
	          NamedNodeMap arr = nodes.item(i).getAttributes();
	          for(int k=0;k<arr.getLength();k++) {
	        	  Node ar = arr.item(k);
	        	  if("name".equals(ar.getNodeName())) {
		        		 stu.setName(ar.getTextContent());
		        	 }
		        	 if("sex".equals(ar.getNodeName())) {
		        		 stu.setSex(ar.getTextContent());
		        	 }
		        	 if("id".equals(ar.getNodeName())) {
		        		 stu.setId(Integer.parseInt(ar.getTextContent()));
		        	 }
		        	 if("score".equals(ar.getNodeName())) {
		        		 stu.setSocre(Integer.parseInt(ar.getTextContent()));
		        	 }
	          }
	          list.add(stu);
		}
		for(Students s:list) {//遍历输出测试
			System.out.println(s);
		}
		
	}
}

运行结果：