xml-day1

什么是xml？

xml和html的区别？

在java中解析xml：

package org.xml.example;

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 Demo2 {
    public static void main(String [] args){
        
        try {
            //创建文件工厂
            DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
            //创建获取文件信息的对象
            DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();
            //获取xml文件对象
            Document document = builder.parse(new File("language.xml"));
            //获取根节点
            Element root = document.getDocumentElement();
            System.out.println("root="+root.getAttribute("cat"));
            
            //使用根节点根据子节点的名称获取子节点的集合
            NodeList nodeList = root.getElementsByTagName("lan");
            for(int i=0;i<nodeList.getLength();i++){
                Element lan = (Element)nodeList.item(i);
                System.out.println("-------------------");
                System.out.println("id="+lan.getAttribute("id"));
                
                //获取lan的子节点
                NodeList childList = lan.getChildNodes();
                for(int j=0;j<childList.getLength();j++){
                    Node node = childList.item(j);
                    if(node instanceof Element){
                        System.out.println(node.getNodeName()+"="+node.getTextContent());
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

<?xml vesion="1.0" encoding="UTF-8"?>
<language cat="it">
    <lan id="1">
        <name>java</name>
        <ide>eclipse</ide>
    </lan>
    <lan id="2">
        <name>c#</name>
        <ide>Visual studio</ide>
    </lan>
    <lan id="3"> 
        <name>c</name>
        <ide>dep</ide>
    </lan>
</language>

执行结果：

遇到的问题总结：

解决方法：