DOM解析器解析增刪改學習筆記
阿新 • • 發佈：2018-04-16
DOM解析器解析XML文件
import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.junit.Test;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
public class Demo2 {
//dom是否將空白字符當作一個有效的元素對待
public static void main(String[] args) throws Exception{
Document document = getDocument();
Element rootElement = document.getDocumentElement();
NodeList nodeList = rootElement.getChildNodes();
System.out.println("共有" + nodeList.getLength()+"個直接元素");
}
@Test
public void create() throws Exception{
Document document = getDocument();
Element newCarElement = document.createElement("汽車");
newCarElement.setTextContent("我的汽車");
Element rootElement = document.getDocumentElement();
//rootElement.appendChild(newCarElement);
rootElement.insertBefore(
newCarElement,
rootElement.getElementsByTagName("汽車").item(1));
write2xml(document);
}
@Test
public void update() throws Exception{
Document document = getDocument();
Element secondCarElement = (Element) document.getElementsByTagName("汽車").item(1);
secondCarElement.getElementsByTagName("產地").item(0).setTextContent("深圳");
secondCarElement.getElementsByTagName("車牌").item(0).getAttributes().getNamedItem("出產時間").setTextContent("2012年");
write2xml(document);
}
@Test
public void delete() throws Exception{
Document document = getDocument();
Element rootElement = document.getDocumentElement();
Element secondCarElement = (Element) rootElement.getElementsByTagName("汽車").item(1);
rootElement.removeChild(secondCarElement);
write2xml(document);
}
private void write2xml(Document document)throws Exception {
//將內存中的document對象寫到外存的xml文件
TransformerFactory tf = TransformerFactory.newInstance();
Transformer transformer = tf.newTransformer();
//源
Source source = new DOMSource(document);
//目
Result result = new StreamResult(new File("src/xml/dom/car.xml"));
transformer.transform(source,result);
}
private static Document getDocument() throws Exception {
DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
//設置dom解析器將空白字符過濾
factory.setIgnoringElementContentWhitespace(true);
DocumentBuilder domParser = factory.newDocumentBuilder();
Document document = domParser.parse(new File("src/xml/dom/car.xml"));
return document;
}
}
DOM解析器解析增刪改學習筆記