Java&Xml教程（七）使用JDOM修改XML文件内容

刺骨的言语ヽ痛彻心扉 2022-08-18 15:17 157阅读 0赞

JDOM提供了非常灵活的方式操作XML文件，使用JDOM非常简单而且代码简洁可读性强。前面我们学习了如何使用JDOM解析XML文件，本节介绍如何使用JDOM修改XML文件内容。  
在这个教程中，我们准备对下面的XML文件进行修改：  
employees.xml

<?xml version="1.0" encoding="UTF-8"?>
    <Employees xmlns="http://www.journaldev.com/employees">
      <Employee id="1">
        <age>25</age>
        <name>Pankaj</name>
        <gender>Male</gender>
        <role>Java Developer</role>
      </Employee>
      <Employee id="2">
        <age>34</age>
        <name>Mona</name>
        <gender>Female</gender>
        <role>Manager</role>
      </Employee>
      <Employee id="3">
        <age>45</age>
        <name>Dave</name>
        <gender>Male</gender>
        <role>Support</role>
      </Employee>
    </Employees>

我们将改变xml中每个Employee元素：  
1.修改所有name元素，使它的内容全部变成大写。  
2.在gender（性别）为Male（男）的id属性值后追加M，gender（性别）为Female（女） 的id属性值后追加F。  
3.删除gender元素。  
4.为每个Employee元素增加salary（薪水）子元素，默认值为1000。  
下面是程序代码：  
JDOMXMLEditor.java

package com.journaldev.xml.jdom;
    
    
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.util.List;
    
    import org.jdom2.Element;
    import org.jdom2.JDOMException;
    import org.jdom2.Namespace;
    import org.jdom2.input.SAXBuilder;
    import org.jdom2.output.Format;
    import org.jdom2.output.XMLOutputter;
    
    
    public class JDOMXMLEditor { 
    
        public static void main(String[] args) throws JDOMException, IOException {
            final Namespace ns = Namespace.getNamespace("http://www.journaldev.com/employees");
    
            //Get the JDOM document
            org.jdom2.Document doc = useSAXParser("employees.xml");
    
            //Get list of Employee element
            Element rootElement = doc.getRootElement();
            List<Element> listEmpElement = rootElement.getChildren("Employee", ns);
    
            //loop through to edit every Employee element
            for (Element empElement : listEmpElement) {
    
                //change the name to BLOCK letters
                String name = empElement.getChildText("name", ns);
                if (name != null)
                    empElement.getChild("name", ns).setText(name.toUpperCase());
    
                //edit the ID attribute based on Gender
                String gender = empElement.getChildText("gender", ns);
                if (gender != null && gender.equalsIgnoreCase("female")) {
                    String id = empElement.getAttributeValue("id");
                    empElement.getAttribute("id").setValue(id + "F");
                } else {
                    String id = empElement.getAttributeValue("id");
                    empElement.getAttribute("id").setValue(id + "M");
                }
    
                //remove gender element as it's not needed anymore
                empElement.removeChild("gender", ns);
    
                //add salary element with default value to every employee
                empElement.addContent(new Element("salary", ns).setText("1000"));
            }
    
            //document is processed and edited successfully, lets save it in new file
            XMLOutputter xmlOutputter = new XMLOutputter(Format.getPrettyFormat());
            //output xml to console for debugging
            //xmlOutputter.output(doc, System.out);
            xmlOutputter.output(doc, new FileOutputStream("employees_new.xml"));
        }
    
    
        //Get JDOM document from SAX Parser
        private static org.jdom2.Document useSAXParser(String fileName) throws JDOMException,
                IOException {
            SAXBuilder saxBuilder = new SAXBuilder();
            return saxBuilder.build(new File(fileName));
        }
    
    }

需要注意的是上面代码使用命名空间获取所有元素，运行程序输出XML文件内容：  
employees\_new.xml

<?xml version="1.0" encoding="UTF-8"?>
    <Employees xmlns="http://www.journaldev.com/employees">
      <Employee id="1M">
        <age>25</age>
        <name>PANKAJ</name>
        <role>Java Developer</role>
        <salary>1000</salary>
      </Employee>
      <Employee id="2F">
        <age>34</age>
        <name>MONA</name>
        <role>Manager</role>
        <salary>1000</salary>
      </Employee>
      <Employee id="3M">
        <age>45</age>
        <name>DAVE</name>
        <role>Support</role>
        <salary>1000</salary>
      </Employee>
    </Employees>