Java学习：使用DOM解析XML

本文是我在学习《Java核心技术》第九版卷II（高级特性）时写的一段代码。原书作者为（美）Cay S. Horstmann，Gary Cornell，译者为陈昊鹏、王浩、姚建平等。我的Java版本为1.8

Java提供了两种XML解析器：树型解释器DOM（Document Object Model，文档对象模型），和流机制解析器SAX（Simple API for XML，XML简单API）。DOM可以将XML转换为树结构。

XML文档内容如下：

文件名：NameList.xml，文件路径：C:\Users\Tsybius\Desktop\NameList.xml

<?xml version="1.0" encoding="UTF-8"?>
<root>
  <list1>
    <person id="101" name="Tsybius" remark="1" />
    <person id="102" name="Galatea" remark="2" />
    <person id="103" name="Quintus" remark="3" />
    <person id="104" name="Atia" remark="4" />
    <person id="105" name="Justitia" remark="5" />
  </list1>
  <list2>
    <person id="201" name="Zhang" remark="a" />
    <person id="202" name="Wang" remark="b" />
    <person id="203" name="Li" remark="c" />
    <person id="204" name="Zhao" remark="d" />
    <person id="205" name="Liu" remark="e" />
  </list2>
  <text>TEXT</text>
</root>

Java代码如下：

package XmlDomTest;

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.NamedNodeMap;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.SAXException;

/**
 * 使用DOM解析XML
 * @author Tsybius
 *
 */
public class XmlDomTest {
    
    /**
     * 使用DOM解析XML
     * @param args
     */
    public static void main(String[] args) {

        try {
            
            String filePath = "C:\\Users\\Tsybius\\Desktop\\NameList.xml";
            File f = new File(filePath);

            DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
            DocumentBuilder builder = factory.newDocumentBuilder();
            Document doc = builder.parse(f);
            
            //遍历节点方式1
            Element root = doc.getDocumentElement();
            System.out.println("根节点名：" + root.getNodeName());
            NodeList children = root.getChildNodes();
            for (int i = 0; i < children.getLength(); i++) {
                Node child = children.item(i);
                if (child instanceof Element) {
                    Element childElement = (Element)child;
                    System.out.println("节点名：" + childElement.getNodeName());
                    
                    if (childElement.getNodeName().equals("list1")) {
                        //list1
                        //遍历节点方式2
                        //获取指定属性
                        for (Node list1Node = childElement.getFirstChild(); 
                                list1Node != null;
                                list1Node = list1Node.getNextSibling()) {
                            if (list1Node instanceof Element) {
                                Element list1Element = (Element)list1Node;
                                System.out.print("person:");
                                System.out.print("id=" + list1Element.getAttribute("id") + ";");
                                System.out.print("name=" + list1Element.getAttribute("name") + ";");
                                System.out.print("remark=" + list1Element.getAttribute("remark") + ";");
                                System.out.println();
                            }
                        }
                        
                    } else if (childElement.getNodeName().equals("list2")) {
                        //list2
                        //遍历节点方式2
                        //遍历所有属性
                        for (Node list2Node = childElement.getFirstChild(); 
                                list2Node != null;
                                list2Node = list2Node.getNextSibling()) {
                            if (!(list2Node instanceof Element)) {
                                continue;
                            }
                            NamedNodeMap attributes = ((Element)list2Node).getAttributes();
                            System.out.print("person:");
                            for (int counter = 0; counter < attributes.getLength(); counter++) {
                                Node attribute = attributes.item(counter);
                                if (attribute == null) {
                                    continue;
                                }
                                String name = attribute.getNodeName();
                                String value = attribute.getNodeValue();
                                System.out.print(name + "=" + value + ";");
                            }
                            System.out.println();
                        }
                        
                    } else if (childElement.getNodeName().equals("text")) {
                        //text
                        //获取文本值
                        Text textNode = (Text)childElement.getFirstChild();
                        String text = textNode.getData().trim();
                        System.out.println("text：" + text);
                    }
                }
            }

        } catch (ParserConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (SAXException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
        
    }
}

控制台中输出结果如下：

根节点名：root
节点名：list1
person:id=101;name=Tsybius;remark=1;
person:id=102;name=Galatea;remark=2;
person:id=103;name=Quintus;remark=3;
person:id=104;name=Atia;remark=4;
person:id=105;name=Justitia;remark=5;
节点名：list2
person:id=201;name=Zhang;remark=a;
person:id=202;name=Wang;remark=b;
person:id=203;name=Li;remark=c;
person:id=204;name=Zhao;remark=d;
person:id=205;name=Liu;remark=e;
节点名：text
text：TEXT

END