xml解析无法使用Java读取xml文档

10 月，3 周 Questions & Answers 199

我试图解析一个XML文件：一个web上的站点地图。我试过很多组合，但都没有成功。我确信我很接近，但我没有发现任何有效的东西

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
org.w3c.dom.Document doc = factory.newDocumentBuilder().parse(new URL("https://www.lavisducagou.nc/page-sitemap.xml").openStream());
System.out.println("XML = " + doc);

输出：

XML = [#document: null]

为什么输出是[#document: null]

文件

（"https://www.lavisducagou.nc/page-sitemap.xml）

它确实是在线的

提前感谢你的帮助

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共 (3) 个答案

# 1 楼答案

实际上，您的XML文档已正确解析和加载。您只是对doc.toString()的相当愚蠢的输出感到恼火（在评估"XML " + doc时在幕后调用）

事先您知道需要的XML标记名（urlset，url，loc，lastmod）以及它们是如何相互嵌套的

要继续了解XML，只需在树中行走即可提取你想要的东西。例如：

public static void main(String[] args) throws Exception {
    DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
    factory.setNamespaceAware(true);
    Document doc = factory.newDocumentBuilder().parse(new URL("https://www.lavisducagou.nc/page-sitemap.xml").openStream());

    // Get the <urlset> root element
    Element urlsetElement = doc.getDocumentElement();

    // Get the list of <url> elements within the <urlset> element
    NodeList urlNodeList = urlsetElement.getElementsByTagName("url");

    for(int i = 0; i < urlNodeList.getLength(); i++) {
        // Get the <url> element
        Element urlElement = (Element) urlNodeList.item(i);

        // Get the <loc> element within the <url> element
        Element locElement = (Element) urlElement.getElementsByTagName("loc").item(0);
        // Print the text content of the <lo> element
        System.out.println("loc = " + locElement.getTextContent());

        // Get the <lastmod> element within the <url> element
        Element lastmodElement = (Element) urlElement.getElementsByTagName("lastmod").item(0);
        // Print the text content of the <lastmod> element
        System.out.println("lastmod = " + lastmodElement.getTextContent());
    }
}

您将得到如下输出：

loc = https://www.lavisducagou.nc/
lastmod = 2018-07-14T11:30:25+11:00
loc = https://www.lavisducagou.nc/sinscrire/
lastmod = 2018-05-03T16:58:35+11:00
loc = https://www.lavisducagou.nc/se-connecter/
lastmod = 2018-05-03T18:02:07+11:00
loc = https://www.lavisducagou.nc/mot-de-passe-oublie/
lastmod = 2018-05-03T20:33:08+11:00
loc = https://www.lavisducagou.nc/compte/
lastmod = 2018-05-03T20:36:32+11:00
...

# 2 楼答案

您需要迭代并查找xml元素。下面是一个在url节点中获取的loc和lastmod节点的解决方案

package com.yourPackage;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.IOException;
import java.net.URL;
import java.text.ParseException;

public class Main {
    public static void main(String[] args) throws ParseException, ParserConfigurationException, IOException, SAXException {
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        factory.setNamespaceAware(true);

        Document doc = factory.newDocumentBuilder().parse(new URL("https://www.lavisducagou.nc/page-sitemap.xml").openStream());
        doc.getDocumentElement().normalize();

        NodeList urlList = doc.getElementsByTagName("url");

        for (int i = 0; i < urlList.getLength(); i++) {
            Element url = (Element)urlList.item(i);

            Node loc = url.getElementsByTagName("loc").item(0);
            Node lastmod = url.getElementsByTagName("lastmod").item(0);

            System.out.println(loc.getTextContent());
            System.out.println(lastmod.getTextContent());
        }

    }
}

输出为：

https://www.lavisducagou.nc/
2018-07-14T11:30:25+11:00
https://www.lavisducagou.nc/sinscrire/
2018-05-03T16:58:35+11:00
https://www.lavisducagou.nc/se-connecter/
2018-05-03T18:02:07+11:00
https://www.lavisducagou.nc/mot-de-passe-oublie/
2018-05-03T20:33:08+11:00
https://www.lavisducagou.nc/compte/
2018-05-03T20:36:32+11:00
https://www.lavisducagou.nc/mon-profil/
2018-05-05T15:18:36+11:00
https://www.lavisducagou.nc/processus-de-paiement/
2018-05-07T15:23:39+11:00
https://www.lavisducagou.nc/paiement/
2018-05-07T23:44:51+11:00
https://www.lavisducagou.nc/historique-des-transactions/
2018-05-12T16:58:30+11:00
https://www.lavisducagou.nc/entreprise-standard/
2018-05-16T23:22:26+11:00
https://www.lavisducagou.nc/entreprise-premium/
2018-05-16T23:25:31+11:00
https://www.lavisducagou.nc/ajouter-une-entreprise/
2018-05-16T23:30:08+11:00
https://www.lavisducagou.nc/a-propos-de-nous/
2018-06-05T18:52:10+11:00
https://www.lavisducagou.nc/se-referencer/
2018-06-07T16:15:39+11:00
https://www.lavisducagou.nc/politique-de-confidentialite/
2018-06-15T09:15:11+11:00
https://www.lavisducagou.nc/donner-un-avis/
2018-06-16T10:55:24+11:00
https://www.lavisducagou.nc/conditions-dutilisation/
2018-06-19T16:39:44+11:00
https://www.lavisducagou.nc/annuaire-des-entreprises/
2018-06-19T20:51:22+11:00
https://www.lavisducagou.nc/pdf-generer/
2018-06-21T00:40:48+11:00
https://www.lavisducagou.nc/generer-pdf/
2018-06-21T00:51:22+11:00
https://www.lavisducagou.nc/contactez-nous/
2018-06-23T15:44:20+11:00
https://www.lavisducagou.nc/modifier-standard/
2018-06-23T20:04:01+11:00
https://www.lavisducagou.nc/pdf-generer-admin/
2018-06-30T19:19:01+11:00
https://www.lavisducagou.nc/conditions-generales-de-vente/
2018-07-02T15:19:51+11:00
https://www.lavisducagou.nc/modifier-standard-lentreprise/
2018-07-04T22:25:30+11:00
https://www.lavisducagou.nc/modifier-lentreprise/
2018-07-04T22:26:25+11:00
https://www.lavisducagou.nc/mentions-legales/
2018-07-27T16:08:01+11:00
https://www.lavisducagou.nc/jeu-concours/
2018-08-22T14:40:53+11:00

# 3 楼答案

您看到的只是com.sun.org.apache.xerces.internal.dom.DocumentImpl的toString实现

public String toString() {
    return "["+getNodeName()+": "+getNodeValue()+"]";
}

因为文档没有节点值，所以它是空的。您需要做的是获取childNodes并进行迭代，以获取所需的详细信息

由于防火墙问题，我无法使用java访问URL，但这里有一个来自同一文件本身的小摘录

<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl"  href="//www.lavisducagou.nc/wp-content/plugins/wordpress-seo/css/main-sitemap.xsl"?>
<urlset xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:image="http://www.google.com/schemas/sitemap-image/1.1" xsi:schemaLocation="http://www.sitemaps.org/schemas/sitemap/0.9 http://www.sitemaps.org/schemas/sitemap/0.9/sitemap.xsd http://www.google.com/schemas/sitemap-image/1.1 http://www.google.com/schemas/sitemap-image/1.1/sitemap-image.xsd" xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://www.lavisducagou.nc/</loc>
    <lastmod>2018-07-14T11:30:25+11:00</lastmod>
  </url>
  <url>
    <loc>https://www.lavisducagou.nc/sinscrire/</loc>
    <lastmod>2018-05-03T16:58:35+11:00</lastmod>
  </url>
</urlset>

刚刚用以下步骤更新了代码：

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
factory.setNamespaceAware(true);
org.w3c.dom.Document doc = factory.newDocumentBuilder().parse(new URL("https://www.lavisducagou.nc/page-sitemap.xml").openStream());
System.out.println("XML = " + doc);
NodeList nodeList = doc.getChildNodes();
for (int i=0; i<nodeList.getLength();i++) {
   System.out.println(nodeList.item(i).getNodeName());
}

样本输出：

XML = [#document: null]
xml-stylesheet
urlset

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xml解析无法使用Java读取xml文档

共 (3) 个答案

# 1 楼答案

# 2 楼答案

# 3 楼答案