1：實體類

public class Book {
    private Integer id;
    private String name;
    private String author;
    private String year;
    private Double price;
    public Book() {
        super();
    }
    public Book(Integer id, String name, String author, String year,
            Double price) {
        super();
        this.id = id;
        this.name = name;
        this.author = author;
        this.year = year;
        this.price = price;
    }
}
 

public class CreatData {
    public static List<Book> getData(){
        List<Book> list=new ArrayList<Book>();
        for (int i = 1; i < 4; i++) {
            Book book =new Book(i, "豬"+i+"戒", "老"+i+"佳", "163"+i, 36.5+i);
            list.add(book);
        }
        return list;
    }
}
 

public class DomCreatXml {
    public static void main(String[] args) {
        new DomCreatXml().creatXml();
    }

    // 返回一個DocumentBuilder物件
    public DocumentBuilder getDocumentBuilder() {
        DocumentBuilder db = null;
        try {
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            db = dbf.newDocumentBuilder();
        } catch (ParserConfigurationException e) {
            e.printStackTrace();
        }
        return db;
    }

    // 建立xml檔案
    private void creatXml() {
        DocumentBuilder db = getDocumentBuilder();
        // 建立文件物件
        Document document = db.newDocument();
        // 設定xml檔案中不顯示 standalone="no"
        document.setXmlStandalone(true);
        // 建立跟節點bookstore
        Element bookstore = document.createElement("bookstore");
        // 獲取book資料
        List<Book> bookList = CreatData.getData();
        // 遍歷，取出list集合中的book資料
        for (int i = 0; i < bookList.size(); i++) {
            // 建立book節點，以及book下面的各次級節點
            Element book = document.createElement("book");
            Element name = document.createElement("name");
            Element author = document.createElement("author");
            Element year = document.createElement("year");
            Element price = document.createElement("price");
            // 取值
            Book bk = bookList.get(i);
            name.setTextContent(bk.getName());
            author.setTextContent(bk.getAuthor());
            year.setTextContent(bk.getYear());
            price.setTextContent(bk.getPrice().toString());
            /**
             * 將book的子節點先新增在book下，將book節點新增到根節點bookstore下，
             * 再將bookstore新增到dom樹下,是一個從最子到父的逐層新增過程
             */
            book.setAttribute("id", bk.getId().toString());
            book.appendChild(name);
            book.appendChild(author);
            book.appendChild(year);
            book.appendChild(price);
            bookstore.appendChild(book);
        }
        document.appendChild(bookstore);
        // 建立TransformerFactory物件
        TransformerFactory tff = TransformerFactory.newInstance();
        try {
            Transformer tf = tff.newTransformer();
            // 設定換行
            tf.setOutputProperty(OutputKeys.INDENT, "yes");
            // 設定生成xml檔案
            tf.transform(new DOMSource(document), new StreamResult(new File(
                    "resouce/creatBook1.xml")));
        } catch (TransformerConfigurationException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (TransformerException e) {
            e.printStackTrace();
        }
    }
}
 

<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
    <book id="1">
        <name>豬1戒</name>
        <author>老1佳</author>
        <year>1631</year>
        <price>37.5</price>
    </book>
    <book id="2">
        <name>豬2戒</name>
        <author>老2佳</author>
        <year>1632</year>
        <price>38.5</price>
    </book>
    <book id="3">
        <name>豬3戒</name>
        <author>老3佳</author>
        <year>1633</year>
        <price>39.5</price>
    </book>
</bookstore>