Java中的XML之四種方式生成XML文檔：DOM，SAX，JDOM，DOM4J

現有以下XML文檔books.xml,下面的示例生成此文檔部分內容

<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
    <book id="1">
        <name>冰與火之歌</name>
        <author>喬治馬丁</author>
        <year>2014</year>
        <price>89</price>
    </book>
    <book id="2">
        <name>安徒生童話</name>
        <year>2004</year>
        <price>77</price>
        <language>English</language>
    </book>
</bookstore>

DOM

1、創建DocumentBuilder對象

DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();

2、添加節點

document.setXmlStandalone(true);
Element bookstore = document.createElement("bookStore");
//向bookstore根節點中添加子節點book
Element book = document.createElement("book");
Element name = document.createElement("name");
name.setTextContent("???");

book.appendChild(name);
book.setAttribute("id", "1");
//將book節點添加到bookstore根節點中
bookstore.appendChild(book);
//將bookstore節點（已經包含了book）添加到dom樹中
document.appendChild(bookstore);

3、生成xml文件

TransformerFactory tff = TransformerFactory.newInstance();
Transformer tf = tff.newTransformer();
//設置文件
tf.setOutputProperty(OutputKeys.INDENT, "yes");
tf.transform(new DOMSource(document),new StreamResult(new File("books1.xml")));

---

SAX

1、創建一個TransformerFactory類的對象

SAXTransformerFactory tff = (SAXTransformerFactory) SAXTransformerFactory.newsInstance();

2、通過SAXTransformerFactory對象創建一個TransformerHandler對象

TransformerHandler handler = tff.newTransformerHandler();

3、通過handler對象創建一個Transformer對象

Transformer tr = handler.getTransformer();

4、通過Transformer對象對生成的xml文件進行設置

// 設置xml的編碼
tr.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
// 設置xml的“是否換行”
tr.setOutputProperty(OutputKeys.INDENT, "yes");
5、創建一個Result對象
```java
File f = new File("newbooks.xml");
if (!f.exists()) {
    f.createNewFile();
}




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6、創建Result對象，並且使其與handler關聯

Result result = new StreamResult(new FileOutputStream(f));
handler.setResult(result);




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7、利用handler對象進行xml文件內容的編寫O

// 打開document
handler.startDocument();




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8、添加節點屬性和節點值

AttributesImpl attr = new AttributesImpl();
handler.startElement("", "", "bookstore", attr);
for (Book book : bookList) {
    attr.clear();
    attr.addAttribute("", "", "id", "", book.getId());
    handler.startElement("", "", "book", attr);
    // 創建name節點
    if (book.getName() != null && !book.getName().trim().equals("")) {
        attr.clear();
        handler.startElement("", "", "name", attr);
        handler.characters(book.getName().toCharArray(), 0, book
                .getName().length());
        handler.endElement("", "", "name");
    }
    handler.endElement("", "", "book");
}
handler.endElement("", "", "bookstore");
// 關閉document
handler.endDocument();




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---

JDOM

1.生成一個根節點

Element rss = new Element("rss");




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2.爲節點添加屬性

rss.setAttribute("version", "2.0");




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3.生成一個document對象

Document document = new Document(rss);
Element channel = new Element("channel");
rss.addContent(channel);
Element title = new Element("title");
title.setText("<![CDATA[上海移動互聯網產業促進中心正式揭牌 ]]>");
channel.addContent(title);
//設置文件編碼和換行
Format format = Format.getCompactFormat();
format.setIndent("");
format.setEncoding("GBK");




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4.創建XMLOutputter的對象

XMLOutputter outputer = new XMLOutputter(format);




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5.利用outputer將document對象轉換成xml文檔

outputer.output(document, new FileOutputStream(new File("rssnews.xml")));




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---

DOM4J

使用DOM4J生成RSS文件

1.創建document對象，代表整個xml文檔

Document document = DocumentHelper.createDocument();




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2.創建根節點rss

Element rss = document.addElement("rss");




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3.向rss節點中添加version屬性

rss.addAttribute("version", "2.0");




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4.生成子節點及節點內容

Element channel = rss.addElement("channel");
Element title = channel.addElement("title");
title.setText("<![CDATA[上海移動互聯網產業促進中心正式揭牌 ]]>");




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5.設置生成xml的格式

OutputFormat format = OutputFormat.createPrettyPrint();
format.setEncoding("GBK");




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6.生成xml文件

File file = new File("rssnews.xml");
XMLWriter writer;
writer = new XMLWriter(new FileOutputStream(file), format);
//設置是否轉義，默認值是true，代表轉義
writer.setEscapeText(false);
writer.write(document);
writer.close();

參閱：
慕課網：Java眼中的XML—文件讀取
java核心技術 卷II：高級特性