dom4j解析简单的xml文件 解析元素并封装到对象

 package cn.itcast.xml;

 import cn.itcast.domain.Book;
 import org.dom4j.Document;
 import org.dom4j.DocumentException;
 import org.dom4j.Element;
 import org.dom4j.Node;
 import org.dom4j.io.SAXReader;
 import org.junit.Before;
 import org.junit.Test;

 import java.io.FileNotFoundException;
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.List;

 public class Dom4jDemo {

     private Document document;

     @Before
     public void init() throws DocumentException {
         SAXReader reader = new SAXReader();
         InputStream is = Dom4jDemo.class.getClassLoader().getResourceAsStream("book.xml");

         document = reader.read(is);
     }

     @Test
     public void parseMethod2() throws DocumentException {
         //获取文档根元素，books
         Element root = document.getRootElement();

         //获取所有book元素
         List<Element> bookElements = root.elements();

         //解析所有book元素，并添加到books集合中
         List<Book> books = new ArrayList<>();

         for (Element bookElement : bookElements) {
             //获取author属性值
             String author = bookElement.attributeValue("author");
             //获取子元素name的文本
             String name = bookElement.element("name").getText();
             //获取子元素price的文本
             String priceStr = bookElement.element("price").getText();
             double price = Double.parseDouble(priceStr);
             //创建对应的book对象，并添加到books集合中
             books.add(new Book(author, name, price));
         }

         //打印
         books.forEach(System.out::println);

     }

     @Test
     public void parseMethod1() throws FileNotFoundException, DocumentException {
         //获取根元素
         Element root = document.getRootElement();
         System.out.println(root.getName());

         List<Book> books = new ArrayList<>();

         //获取所有book元素，解析并保存到books集合中。
         List<Node> bookNodes = document.selectNodes("/books/book");
         for (Node bookNode : bookNodes) {
             //获取作者
             String author = bookNode.valueOf("@author");
 //            System.out.println(author);

             /*
                 斜杠开头表示文档，中间的斜杠则表示直接子节点
                 错误代码：
                     String name = bookNode.valueOf("/name");
                     表示选区文档下的name元素，而文档下只有books元素。
              */
             //获取书名
             List<Node> nameNodes = bookNode.selectNodes("name");
             String bookName = nameNodes.get(0).getText();
 //            System.out.println(bookName);

             //获取价格
             List<Node> priceNodes = bookNode.selectNodes("price");
             double price = (double) Double.parseDouble(priceNodes.get(0).getText());

             books.add(new Book(author, bookName, price));
         }

         //打印结果
         books.forEach(System.out::println);
     }
 }

Dom4jDemo.java

 package cn.itcast.domain;

 public class Book {
     private String author;
     private String name;
     private Double price;

     public Book(){}

     public Book(String author, String name, Double price) {
         this.author = author;
         this.name = name;
         this.price = price;
     }

     public String getAuthor() {
         return author;
     }

     public void setAuthor(String author) {
         this.author = author;
     }

     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public Double getPrice() {
         return price;
     }

     public void setPrice(Double price) {
         this.price = price;
     }

     @Override
     public String toString() {
         return "Book{" +
                 "author='" + author + '\'' +
                 ", name='" + name + '\'' +
                 ", price=" + price +
                 '}';
     }
 }

Book.java

 <?xml version="1.0" encoding="UTF-8"?>
 <books>
     <book author="天蚕土豆">
         <name>斗破苍穹</name>
         <price>86</price>
     </book>
     <book author="萧潜">
         <name>缥缈之旅</name>
         <price>92</price>
     </book>
     <book author="萧鼎">
         <name>诛仙</name>
         <price>98</price>
     </book>
     <book author="天下霸唱">
         <name>鬼吹灯</name>
         <price>124</price>
     </book>
     <book author="辰东">
         <name>神墓</name>
         <price>128</price>
     </book>
 </books>

book.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <project xmlns="http://maven.apache.org/POM/4.0.0"
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>

     <groupId>cn.itcast.xml-parser</groupId>
     <artifactId>xml-parser-demo1</artifactId>
     <version>1.0-SNAPSHOT</version>

     <dependencies>
         <!-- https://mvnrepository.com/artifact/org.dom4j/dom4j -->
         <dependency>
             <groupId>org.dom4j</groupId>
             <artifactId>dom4j</artifactId>
             <version>2.1.1</version>
         </dependency>

         <!-- https://mvnrepository.com/artifact/jaxen/jaxen -->
         <dependency>
             <groupId>jaxen</groupId>
             <artifactId>jaxen</artifactId>
             <version>1.1.6</version>
         </dependency>

         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.12</version>
         </dependency>
     </dependencies>

 </project>

pom.xml

 package cn.itcast.xml;

 import org.dom4j.Document;
 import org.dom4j.Element;
 import org.dom4j.io.SAXReader;
 import org.junit.Test;

 import java.util.List;
 /*
 作者：北冥有鱼_很好吃
 链接：https://www.jianshu.com/p/806bb1bdc06f
  */
 public class Dom4j_02{

     @Test
     public void parse() throws Exception {
         // 1. 创建一个 saxReader 对象
         SAXReader saxReader = new SAXReader();
         // 2. 将数据读取到 document 对象中
         Document document = saxReader.read(Dom4j_02.class.getClassLoader().getResourceAsStream("servlet.xml"));
         // 3. 使用 document 对象调用 getRootElement 方法获取根标签, 返回 Element 接口实现类对象
         Element rootElement = document.getRootElement();
         // 4. 使用 rootElement 根标签对象调用 elements 方法, 传入 servlet, 获取servlet标签对象
         List<Element> servletElements = rootElement.elements("servlet");
         // 5. 遍历, 并获取该标签下的子标签数据内容, 使用父标签对象调用elementText方法, 传入子标签名称获取数据
         for (Element servlet : servletElements) {
             String name = servlet.elementText("servlet-name");
             String cls = servlet.elementText("servlet-class");
             System.out.println(name + " : " + cls);
         }
         // 使用 rootElement 根标签对象调用 elements 方法, 传入 servlet-mapping, 获取servlet-mapping标签对象
         List<Element> mappingElements = rootElement.elements("servlet-mapping");
         for (Element mapping : mappingElements) {
             String name = mapping.elementText("servlet-name");
             String url = mapping.elementText("url-pattern");
             System.out.println(name + " = " + url);
         }
     }
 }

Dom4j_02.java 解析servlet.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <!--
 作者：北冥有鱼_很好吃
 链接：https://www.jianshu.com/p/806bb1bdc06f
 -->
 <servlets>
     <servlet>
         <servlet-name>servlet1</servlet-name>
         <servlet-class>MyServlet1</servlet-class>
     </servlet>
     <servlet>
         <servlet-name>servlet2</servlet-name>
         <servlet-class>MyServlet2</servlet-class>
     </servlet>
     <servlet-mapping>
         <servlet-name>servlet1</servlet-name>
         <url-pattern>/s1</url-pattern>
     </servlet-mapping>
     <servlet-mapping>
         <servlet-name>servlet2</servlet-name>
         <url-pattern>/s2</url-pattern>
     </servlet-mapping>
 </servlets>

servlet.xml