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);
    }
}

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 +
                '}';
    }
}

<?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>

<?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>

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);
        }
    }
}

<?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>