使用Dom操作xml

 使用dom输出一个xml文件中的内容


1 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.NodeList;
import org.xml.sax.SAXException;

public class dom{
    public static void main(String args[]){
        
        
        //取得DocumentBuilderFactory类的对象
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        //取得DocumentBuilder类的对象
        try {
            DocumentBuilder builder = factory.newDocumentBuilder();
            
            Document doc =builder.parse(new File("src//dom.xml"));
            NodeList list = doc.getElementsByTagName("name");
            //输出节点
            System.out.println("姓名 : " + list.item(0).getFirstChild().getNodeValue());
            
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        
        
        
        
    }
}

此为上述使用的xml

<?xml version="1.0" encoding="GBK"?>
<addresslist>
    <name>张浩威</name>
</addresslist>

输出结果




姓名 : 张浩威

较为复杂的xml文件可以用循环访问

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.NodeList;
import org.xml.sax.SAXException;

public class dom2{
    public static void main(String args[]){
        
        
        //取得DocumentBuilderFactory类的对象
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        //取得DocumentBuilder类的对象
        try {
            DocumentBuilder builder = factory.newDocumentBuilder();
            
            Document doc =builder.parse(new File("src//dom1.xml"));
            
            //得到所有linkman的节点
            NodeList list = doc.getElementsByTagName("listman");
            //输出节点
            for(int i = 0 ; i < list.getLength() ; i++ ){
            
                Element e = (Element)list.item(i);
                System.out.println("姓名 : " + e.getElementsByTagName("name").item(0).getFirstChild().getNodeValue());
                System.out.println("邮箱 : " + e.getElementsByTagName("email").item(0).getFirstChild().getNodeValue());
            }
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (SAXException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        
        
        
        
        
    }
}

<?xml version="1.0" encoding="GBK"?>
<addresslist>
    <listman>
    <name>张浩威</name>
    <email>287877150@qq.com</email>
    </listman>
    <listman>
    <name>张浩龙</name>
    <email>94397959@qq.com</email>
    </listman>
</addresslist>

输出结果:



姓名 : 张浩威
邮箱 : 287877150@qq.com
姓名 : 张浩龙
邮箱 : 94397959@qq.com

也可以用dom来生成xml文件

import java.io.File;
import java.io.IOException;


import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
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;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;


//Dom操作除了可以进行解析之外还可以进行文件的生成
public class dom3{
    public static void main(String args[]){
        
        
        //取得DocumentBuilderFactory类的对象
        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
        //取得DocumentBuilder类的对象
        try {
            DocumentBuilder builder = factory.newDocumentBuilder();
            
            //创建一个新的xml文档
            Document doc =builder.newDocument();
            Element addresslist = doc.createElement("addresslist");
            Element listman = doc.createElement("listman");
            Element name = doc.createElement("name");
            Element email = doc.createElement("email");
            
            //设置节点内容
            name.appendChild(doc.createTextNode("张浩威"));
            email.appendChild(doc.createTextNode("287877150@qq.com"));
            //设置各节点的关系
            //将节点name 和 email设置为listman的子节点
            listman.appendChild(name);
            listman.appendChild(email);
            //将listman设置为addresslist的子节点
            addresslist.appendChild(listman);
            //设置根节点
            doc.appendChild(addresslist);

            //得到所有linkman的节点
            NodeList list = doc.getElementsByTagName("listman");
            //这段代码的关键是将文档内容保存在文件中
            TransformerFactory tf = TransformerFactory.newInstance();
            Transformer transformer = tf.newTransformer();
            //设置输出编码
            transformer.setOutputProperty(OutputKeys.ENCODING, "GBK");
            //准备输出文档
            DOMSource source = new DOMSource(doc);
            StreamResult result = new StreamResult(new File("dom2.xml"));
            transformer.transform(source, result);
            
            
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        } catch (TransformerConfigurationException e) {
            e.printStackTrace();
        } catch (TransformerException e) {
            e.printStackTrace();
        } 
        
        
        //此时可以完成文档的输出操作,但是输出后的xml文档格式非常不好
        //对于dom操作既可以读取也可以输出和修改,更多的操作在于读取
        
        
    }
}

输出结果
格式很难看,但是符合标准
<?xml version="1.0" encoding="GBK" standalone="no"?><addresslist><listman><name>张浩威</name><email>287877150@qq.com</email></listman></addresslist>