Detailed explanation of the process of parsing XML files with Java DOM

This article mainly introduces the detailed explanation of the process of parsing XML files by Java dom. It is introduced in great detail through the example code, which has a certain reference value for everyone's study or work. Friends in need can refer to it

The code is as follows

import java.io.IOException;
import javax.xml.parsers.*;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class Domtest {

  public static void main(String[] args) throws ParserConfigurationException,SAXException,IOException {
    //创建一个DocumentBuilderFactory对象
    DocumentBuilderFactory dbf=DocumentBuilderFactory.newInstance();
    //创建一个Doucumentbuild对象
    DocumentBuilder db=dbf.newDocumentBuilder();
    //解析对应的xml文件
    Document doc=db.parse("tes.xml");
    //根据标签名获取Node节点list
    NodeList nodelist=doc.getElementsByTagName("book");
    System.out.println("共有"+nodelist.getLength()+"本书");
    //遍历每一个book节点
    for(int i=0;i<nodelist.getLength();i++) {
      System.out.println("第"+i+"本书");
      //获取个book节点
      //使用Node类型获取book
      Node book=nodelist.item(i);
      System.out.println("Name: "+book.getNodeName()+" Value: "+book.getNodeValue()+" Type: "+book.getNodeType());
      //获取Node节点中的属性
      NamedNodeMap attrs= book.getAttributes();
      //遍历获取属性
      for(int j=0;j<attrs.getLength();j++) {
      Node x=attrs.item(j);
      //System.out.println(x.getNodeName()+" "+x.getNodeValue()+" "+x.getNodeType());
      }

      //使用Element对象获取节点
      Element node =(Element) nodelist.item(i);
      //使用Element对象下的getAttribute方法可以获取指定名字的属性值
      String id=node.getAttribute("id");
      System.out.println(id);
      String type=node.getAttribute("type");
      System.out.println(type);

      //使用Node节点下的getChildNode可以获取Nodelist数组，以此进行循环解析
      NodeList childnode=book.getChildNodes();
      for(int j=0;j<childnode.getLength();j++) {//getLength后会获取9个节点，因为text类型也算节点，一个<name>……</name>算一个节点，所以共有9个节点，而这些节点中，只有对象节点是我们需要的
        Node x=childnode.item(j);
        if(x.getNodeType()==Node.ELEMENT_NODE){//当节点类型为Element时，获取该节点
          //获取element类型的节点名
          System.out.println("节点"+j+"的名字:"+x.getNodeName()+" 值:/"+x.getLastChild().getNodeValue()+"/种类为"+x.getLastChild().getNodeType());//<name>xyz<name>，xyz属于<name>的子节点,使用getfirstChild或getLastNode效果相同
          System.out.println("节点"+j+"的名字:"+x.getNodeName()+" 值:/"+x.getTextContent()+"/种类为"+x.getNodeType());//getTextContent方法可以获取节点中所有的text内容 将<name>xyz</name>改为<name><a>123</a>xyz</name>,会获取到xyz123
        }
      }
    }
  }
}
//为了将获取到的xml文件中内容保存下来，可以将内容保存到对象数组中一次来存储数据

<?xml version="1.0" encoding="UTF-8" ?>
<Bookstore>
  <book id="1" type="text">
  <name>冰与火之歌</name>
  <author>乔治马丁</author>
  <year>2014</year>
  <price>80</price>
  </book>
<book id="2">
  <name>安徒生童话</name>
  <year>2004</year>
  <price>79</price>
  <language>English</language>
</book>
</Bookstore>

Attention

1. Blank line breaks are also nodes, so when traversing nodes, you should pay attention that these useless nodes will be mixed in the list

2. The name value returned by the text node is #text, while the value value returned by the element node is null. Please note that

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