使用DOM的XML生成未格式化

Question

我正在使用DOM生成xml文件,并且程序正常工作并生成文件和输出,但格式如果xml文件不是我所期望的.

这是程序:

    package com.mkyong.core;

import java.io.File;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.Transformer;
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.Attr;
import org.w3c.dom.Document;
import org.w3c.dom.Element;

public class WriteXMLFile {

    public static void main(String argv[]) {

      try {

        DocumentBuilderFactory docFactory = DocumentBuilderFactory.newInstance();
        DocumentBuilder docBuilder = docFactory.newDocumentBuilder();

        // root elements
        Document doc = docBuilder.newDocument();
        Element rootElement = doc.createElement("company");
        doc.appendChild(rootElement);

        // staff elements
        Element staff = doc.createElement("Staff");
        rootElement.appendChild(staff);

        // set attribute to staff element
        Attr attr = doc.createAttribute("id");
        attr.setValue("1");
        staff.setAttributeNode(attr);

        // shorten way
        // staff.setAttribute("id", "1");

        // firstname elements
        Element firstname = doc.createElement("firstname");
        firstname.appendChild(doc.createTextNode("yong"));
        staff.appendChild(firstname);

        // lastname elements
        Element lastname = doc.createElement("lastname");
        lastname.appendChild(doc.createTextNode("mook kim"));
        staff.appendChild(lastname);

        // nickname elements
        Element nickname = doc.createElement("nickname");
        nickname.appendChild(doc.createTextNode("mkyong"));
        staff.appendChild(nickname);

        // salary elements
        Element salary = doc.createElement("salary");
        salary.appendChild(doc.createTextNode("100000"));
        staff.appendChild(salary);

        // write the content into xml file
        TransformerFactory transformerFactory = TransformerFactory.newInstance();
        Transformer transformer = transformerFactory.newTransformer();
        DOMSource source = new DOMSource(doc);
        StreamResult result = new StreamResult(new File("C:\\file.xml"));

        // Output to console for testing
        // StreamResult result = new StreamResult(System.out);

        transformer.transform(source, result);

        System.out.println("File saved!");

      } catch (ParserConfigurationException pce) {
        pce.printStackTrace();
      } catch (TransformerException tfe) {
        tfe.printStackTrace();
      }
    }
}

问题是这是以下列格式生成xml文件:

<?xml version="1.0" encoding="UTF-8" standalone="no" ?><company><staff id="1"><firstname>yong</firstname><lastname>mook kim</lastname><nickname>mkyong</nickname><salary>100000</salary></staff></company>

但我想要以下格式的文件

<?xml version="1.0" encoding="UTF-8" standalone="no" ?> 
<company>
    <staff id="1">
        <firstname>yong</firstname>
        <lastname>mook kim</lastname>
        <nickname>mkyong</nickname>
        <salary>100000</salary>
    </staff>
</company>

有什么办法可以格式化生成的文件,或者我必须编写自己的xml构建器.

Answer 1

尝试将OutputKeys.INDENT属性设置为值"yes":

transformer.setOutputProperty(OutputKeys.INDENT, "yes");
transformer.transform(source, result);