java - 无法使用 JDOM 从 XML 获取子属性

Question

我试图获取示例 XML 文件中每个人的姓名，但得到的是 null 值而不是他们的姓名。

Java代码:

package testjdom;

import java.io.IOException;
import java.util.List;
import org.jdom2.Document;
import org.jdom2.Element;
import org.jdom2.JDOMException;
import org.jdom2.input.SAXBuilder;

public class TestJDOM {

    public static void main(String[] args) throws
            JDOMException,
            IOException {

        SAXBuilder jdomBuilder
                = new SAXBuilder();
        Document jdomDocument
                = jdomBuilder.build("persons.xml");

        Element jdomRoot = jdomDocument.getRootElement();

        List<Element> children = jdomRoot.getChildren();
        for (Element child : children) {
            System.out.println(child.getAttributeValue("name"));
        }
    }
}

XML:

<?xml version="1.0" encoding="UTF-8"?>
<persons>
  <person>
    <id>1</id>
    <name>The Best</name>
    <email><a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="0f7b676a616a777b6d66687b676661684f68626e6663216c6062" rel="noreferrer noopener nofollow">[email protected]</a></email>
    <birthDate>1981-11-23</birthDate>
  </person>
  <person>
    <id>2</id>
    <name>Andy Jr.</name>
    <email><a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="c9bcbaa889aea4a8a0a5e7aaa6a4" rel="noreferrer noopener nofollow">[email protected]</a></email>
    <birthDate>1982-12-01</birthDate>
  </person>
  <person>
    <id>3</id>
    <name>JohnDoe</name>
    <email><a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="d4b3b5b9b1bba2b1a694b3b9b5bdb8fab7bbb9" rel="noreferrer noopener nofollow">[email protected]</a></email>
    <birthDate>1990-01-02</birthDate>
  </person>
  <person>
    <id>4</id>
    <name>SomeOne</name>
    <email><a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="017374626a7260626a41666c60686d2f626e6c" rel="noreferrer noopener nofollow">[email protected]</a></email>
    <birthDate>1988-01-22</birthDate>
  </person>
  <person>
    <id>5</id>
    <name>Mr. Mxyzptlk</name>
    <email><a href="https://stackoverflow.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="36545f515b5758765e59425b575f5a1855595b" rel="noreferrer noopener nofollow">[email protected]</a></email>
    <birthDate>1977-08-12</birthDate>
  </person>
</persons>

如何获取每个名称的真实值？

最终我想从 XML 中获取每个人的四个值。我有一个名为 Person 的类，它具有与 XML 文件中的人员相同的属性、id、名称等。我想从“Person”类创建新对象，并使用XML 中的数据。当我创建一个新对象并使用从 XML 获取的值成功设置其属性时，我想将该对象添加到 ArrayList，然后对其余人员重复相同的过程。

Answer 1

你有两个问题。 name 不是一个属性，它是一个子元素。其次，getChildren() 仅下降一级。

改变

    Element jdomRoot = jdomDocument.getRootElement();

    List<Element> children = jdomRoot.getChildren();
    for (Element child : children) {
        System.out.println(child.getAttributeValue("name"));
    }

至

    Element jdomRoot = jdomDocument.getRootElement();

    List<Element> people = jdomRoot.getDescendants(new ElementFilter("person"));
    for (Element person: people) {
        System.out.println(person.getChild("name").getText());
    }