xml介绍+xml创建+xml读取

1.xml介绍:(URL:https://blog.csdn.net/weixin_37861326/article/details/81082144)

xml是用来传输内容的,是w3c推荐的

2.使用java创建xml数据,CreateXml.java

package testcreatexml;

import java.io.File;
import java.io.StringWriter;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;

import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class CreateXml {

public static void main(String[] args) {
try {

//DOM
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document document = builder.newDocument();
Element root = document.createElement("Languages");
root.setAttribute("cat", "it");

Element lan1 = document.createElement("lan");
lan1.setAttribute("id", "1");
Element name1 = document.createElement("name");
name1.setTextContent("Java");
Element ide1 = document.createElement("ide");
ide1.setTextContent("Eclipse");
lan1.appendChild(name1);
lan1.appendChild(ide1);

Element lan2 = document.createElement("lan");
lan2.setAttribute("id", "2");
Element name2 = document.createElement("name");
name2.setTextContent("Swift");
Element ide2 = document.createElement("ide");
ide2.setTextContent("XCode");
lan2.appendChild(name2);
lan2.appendChild(ide2);

Element lan3 = document.createElement("lan");
lan3.setAttribute("id", "3");
Element name3 = document.createElement("name");
name3.setTextContent("C#");
Element ide3 = document.createElement("ide");
ide3.setTextContent("Visual Studio");
lan3.appendChild(name3);
lan3.appendChild(ide3);

root.appendChild(lan1);
root.appendChild(lan2);
root.appendChild(lan3);
document.appendChild(root);

//-------------

TransformerFactory transformerFactory = TransformerFactory.newInstance();
Transformer transformer = transformerFactory.newTransformer();
transformer.setOutputProperty("encoding", "UTF-8");

StringWriter writer = new StringWriter();
transformer.transform(new DOMSource(document), new StreamResult(writer));
System.out.println(writer.toString());

transformer.transform(new DOMSource(document), new StreamResult(new File("newxml.xml")));

} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (TransformerConfigurationException e) {
e.printStackTrace();
} catch (TransformerException e) {
e.printStackTrace();
}
}

}

生成xml内容截图:

运行run as-->java application -->refresh工程就能看到newxml.xml文件创建出来了

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3.使用java读取xml数据: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 {

public static void main(String[] args) {
try {

//DOM
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
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"));

NodeList clist = lan.getChildNodes();
for (int j = 0; j < clist.getLength(); j++) {
Node c = clist.item(j);
if (c instanceof Element) {
System.out.println(c.getNodeName()+"="+c.getTextContent());
}
}
}

} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}

}