使用java读取/解析XML数据

朱雀 2021-10-06 14:16 340阅读 0赞

## DOM方式解析XML ##

### 在根目录下新建languages.xml文件，其内容为 ###

<?xml version="1.0" encoding="UTF-8"?>
    <languages cat = "it">
        <lan id="1">
            <name>java</name>
            <ide>Eclipse</ide>
        </lan>
        <lan id="2">
            <name>Swift</name>
            <ide>Xcode</ide>
        </lan>
        <lan id="3">
            <name>C#</name>
            <ide>Visual Studio</ide>
        </lan>
    </languages>

### ReadXML.java ###

import java.io.File;
    import java.io.IOException;
    
    import javax.xml.parsers.DocumentBuilder;
    import javax.xml.parsers.DocumentBuilderFactory;
    import javax.xml.parsers.ParserConfigurationException;
    
    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;
    
    public class ReadXML {
        //使用java读取XML数据
        public static void main(String[] args) {
            //DOM 方式解析XML
            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            try {
                DocumentBuilder builder = factory.newDocumentBuilder();
                Document document = builder.parse(new File("languages.xml"));
                Element root = document.getDocumentElement();
                System.out.println("cat="+root.getAttribute("cat"));
                NodeList list = root.getElementsByTagName("lan");
                for(int i=0;i<list.getLength();i++){ 
                    Element lan = (Element) list.item(i);
                    System.out.println("----------");
                    System.out.println("id="+lan.getAttribute("id"));
    
                    /* * 获取其子节点时，通过getElementsByTagName获取NodeList的方式获取，效率较低，故不推荐 */
                    //  Element name = (Element) lan.getElementsByTagName("name").item(0);
                    //  System.out.println("name="+name.getTextContent());
    
                    //推荐使用：getChildNodes()
                    NodeList child = lan.getChildNodes();
                    for(int j=0;j<child.getLength();j++){ 
                        Node element = child.item(j);
                        if(element instanceof Element){
                            System.out.println(element.getNodeName()+"="+element.getTextContent());
                        }
                    }
    
                }
            } catch (ParserConfigurationException e) {
                e.printStackTrace();
            } catch (SAXException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    
    }

### 运行后的结果为： ###

cat=it ----------
    id=1
    name=java
    ide=Eclipse ----------
    id=2
    name=Swift
    ide=Xcode ----------
    id=3
    name=C#
    ide=Visual Studio