XML解析

我就是我 2024-03-16 21:02 50阅读 0赞

**目录**

一.DOM

2.XPath方式

3.dom4j

1.引入依赖

2.application.xml

3.BeanDefine.java

--------------------

## 一.DOM ##

studentx.xml

<?xml version="1.0"?> 
    <students> 
      <student> 
        <name>John</name> 
        <grade>B</grade> 
        <age>12</age> 
      </student> 
      <student> 
        <name>Mary</name> 
        <grade>A</grade> 
        <age>11</age> 
      </student> 
      <student> 
        <name>Simon</name> 
        <grade>A</grade> 
        <age>18</age> 
      </student> 
    </students>

XMLParser.java

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.Node;  
    import org.w3c.dom.NodeList;  
       
    public class XMLParser {
    	public void getAllUserNames(String fileName) {  
    	    try {
    			//1.获得一个文档解析器工厂：定义工厂API,使应用程序能够从XML文档获取生成DOM对象树的解析器
    			DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();  
    			//2.获得一个文档解析器：定义从XML文档获取DOM文档实例的API。 使用这个类，应用程序员可以从XML获得一个Document 。
    			DocumentBuilder db = dbf.newDocumentBuilder();  
    			 
    			File file = new File(fileName);  
    			if (file.exists()) {  
    				//3.解析器解析xmL文件，获得一个DOM文档
    				Document doc = db.parse(file);  
    				
    				//4.通过DOM文档获取根结点元素，并打印
    				Element docEle = doc.getDocumentElement();  
    				System.out.println("Root element of the document: "+ docEle.getNodeName());  
    				   
    				//5.通过DOM文档根据标签名获取所有其对应的结点，并将其存储在NodeList抽象集合中
    				NodeList studentList = docEle.getElementsByTagName("student");  
    				System.out.println("Total students: " + studentList.getLength());  
    				 
    				//6.打印"student"结点下所有的结点信息
    				if(studentList != null && studentList.getLength() > 0) {  
    					for(int i = 0; i < studentList.getLength(); i++) {  
    						//7.遍历一个"student"结点
    						Node node = studentList.item(i);  
    						//8.node.getNodeType() == Node.ELEMENT_NODE，表示node结点是一个Element(一组)
    						if(node.getNodeType() == Node.ELEMENT_NODE) {  
    							System.out.println("=====================");  
    							  
    							Element e = (Element) node;  
    							NodeList nodeList = e.getElementsByTagName("name");  
    							System.out.println("Name: "+ nodeList.item(0).getChildNodes().item(0).getNodeValue());  
    							   
    							nodeList = e.getElementsByTagName("grade");
    							System.out.println("Grade: "+nodeList.item(0).getChildNodes().item(0)  .getNodeValue());  
    							  
    							nodeList = e.getElementsByTagName("age");  
    							System.out.println("Age: "+ nodeList.item(0).getChildNodes().item(0).getNodeValue());  
    						}
    					}  
    				}
    			}
    		} catch (Exception e) {  
    			System.out.println(e);  
    		}  
    	}  
      
    	public static void main(String[] args) {  
    		XMLParser parser = new XMLParser();  
    		parser.getAllUserNames("./src/students.xml");  
    	}  
    }

![a8447a750fd84c6a88eb4f5abca975de.png][]

## 2.[XPath][]方式 ##

users.xml

<?xml version="1.0"?> 
    <users>
    	<user id="1">
    		<name>张三</name>
    		<createTime>2018-10-15</createTime>
    		<password>123</password>
    		<phone>10086</phone>
    		<nickName>阿毛</nickName>
    	</user>
    	<user id="2">
    		<name>李四</name>
    		<createTime>2018-10-15</createTime>
    		<password>234</password>
    		<phone>12306</phone>
    		<nickName>二狗子</nickName>
    	</user>
    </users>

import java.text.DateFormat;
    import java.text.ParseException;
    import java.text.SimpleDateFormat;
    import java.util.Date;
     
    public class UserEntity {
    	private Long id;
    	private String name;
    	private Date createTime;
    	private String password;
    	private String phone;
    	private String nickName;
     
    	static UserEntity buildUserEntity(String id, String name, String createTime, String password, String phone,
    			String nickName) throws ParseException {
    		UserEntity user=new UserEntity();
    		user.id=Long.valueOf(id);
    		user.name=name;
    		user.createTime=new SimpleDateFormat("yyyy-MM-dd").parse(createTime);
    		user.password=password;
    		user.nickName=nickName;
    		return user;
    	}
    	
    	@Override
    	public String toString() {
    		// TODO Auto-generated method stub
    		return id+"-"+name+"-"+createTime+"-"+password+"-"+nickName;
    	}
    }

import java.io.File;
    import java.io.FileReader;
    import java.util.ArrayList;
    import java.util.Date;
    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.XPathFactory;
     
    import org.w3c.dom.Document;  
    import org.w3c.dom.Element;  
    import org.w3c.dom.Node;  
    import org.w3c.dom.NodeList;  
       
    public class XMLParser {  
       
      public void getAllUserNames(String fileName) {  
        try {
          //1.获得一个文档解析器工厂：定义工厂API,使应用程序能够从XML文档获取生成DOM对象树的解析器
          DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();  
          //2.获得一个文档解析器：定义从XML文档获取DOM文档实例的API。 使用这个类，应用程序员可以从XML获得一个Document 。
          DocumentBuilder builder = dbf.newDocumentBuilder();  
          File file=new File(fileName);
          //3.通过解析器解析xml文件，获得一个文档对象
          Document document=builder.parse(file);
          
          //4.获取新的XPathFactory实例
          XPathFactory xpathFactory=XPathFactory.newInstance();
          //5.一个XPathFactory实例可以用来创建XPath对象
          XPath xpath=xpathFactory.newXPath();
          //6.xpath根据根结点"users"标签解析document文档
          NodeList nodeList=(NodeList) xpath.evaluate("/users/*", document,XPathConstants.NODESET);
          
          //7.获取一个ArrayList实例用来存储UserEntity对象
          List<UserEntity> userList=new ArrayList<UserEntity>();
         
          //8.获取所有的user结点
          for(int i=1;i<nodeList.getLength()+1;i++) {
        	String path="/users/user["+i+"]";
        	String id=(String) xpath.evaluate(path+"/@id", document,XPathConstants.STRING);
        	String name=(String) xpath.evaluate(path+"/name", document,XPathConstants.STRING);
        	String createTime=(String) xpath.evaluate(path+"/createTime", document,XPathConstants.STRING);
        	String password=(String) xpath.evaluate(path+"/password", document,XPathConstants.STRING);
        	String phone=(String) xpath.evaluate(path+"/phone", document,XPathConstants.STRING);
        	String nickName=(String) xpath.evaluate(path+"/nickName", document,XPathConstants.STRING);
        	
        	//调用buildUserEntity()方法构建UserEntity对象
        	UserEntity userEntity=UserEntity.buildUserEntity(id,name,createTime,password,phone,nickName);
        	userList.add(userEntity);
        	
          }
          
          for(UserEntity user:userList) {
        	  System.out.println(user);
          }
          
        }catch(Exception e){
        	e.getMessage();
        }
          
      }  
     
    	public static void main(String[] args) {  
    	    XMLParser parser = new XMLParser();  
    	    parser.getAllUserNames("./src/users.xml");  
    	}  
    }

![a78694e645ac47e9b07f7045191f6c9c.png][]

## 3.dom4j ##

### **1.引入依赖** ###

<dependency>
    	    <groupId>dom4j</groupId>
    	    <artifactId>dom4j</artifactId>
    	    <version>1.6.1</version>
    	</dependency>

### **2.application.xml** ###

<?xml version="1.0" encoding="UTF-8"?>
    <beans>
        <bean id="userDao" class="cn.yiguang.testProject.annotation.UserDaoImpl"></bean>
        <bean id="user1Dao" class="cn.yiguang.testProject.annotation.User1DaoImpl"></bean>
        <bean id="user2Dao" class="cn.yiguang.testProject.annotation.User2DaoImpl"></bean>
        <bean id="userService" class="cn.yiguang.testProject.annotation.UserServiceImpl"></bean>
    </beans>

### **3.BeanDefine.java** ###

public class BeanDefine {
    	private String id;
    	private String className;
    	
    	public BeanDefine(String id, String className) {
    		this.id = id;
    		this.className = className;
    	}
     
    	public String getId() {
    		return id;
    	}
     
    	public void setId(String id) {
    		this.id = id;
    	}
     
    	public String getClassName() {
    		return className;
    	}
     
    	public void setClassName(String className) {
    		this.className = className;
    	}
    	
    	@Override
    	public String toString() {
    		return "id:"+id+",className:"+className;
    	}
    	
    	
    }

**4.测试**

import java.util.Iterator;
     
    import org.dom4j.Document;
    import org.dom4j.DocumentException;
    import org.dom4j.Element;
    import org.dom4j.io.SAXReader;
     
    public class Test {
    	public static void main(String[] args) {
    		
    		// 读取xml文件,转换成Document结点
    		Document document = null;
    		// 创建一个SAXReader解析器
    		SAXReader saxReader = new SAXReader();
    		try {
    			ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
    			document = saxReader.read(classLoader.getResourceAsStream("configAnnotation.xml"));
    			Element beans = document.getRootElement();
    			for (Iterator<Element> beansList = beans.elementIterator();beansList.hasNext();) {
    				Element element = beansList.next();
    				BeanDefine bean = new BeanDefine(element.attributeValue("id"), element.attributeValue("class"));
    				System.out.println(bean.toString());
    				
    			}
    		}catch (DocumentException e){
    			System.out.println("解析配置文件出错......");
    		}
    	}
    }

[a8447a750fd84c6a88eb4f5abca975de.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/5c8eba577b274159a4ff5207d66f1cec.png
[XPath]: https://so.csdn.net/so/search?q=XPath&spm=1001.2101.3001.7020
[a78694e645ac47e9b07f7045191f6c9c.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/03/15/eedd7318dbd646f9bbe8074582e989fd.png