DOM4J

1.读取XML文件

public Document readXML(String fileName) throws Exception

{

    SAXReader sReader = new SAXReader();

    Document doc = sReader.read(new File(fileName));

    return doc;    

}

其中read可以是File，Url，InputStream

 

2.取得Root节点

public Element getRoot（Document doc）

{

    return doc.getRootElement;

}

 

3.遍历XML树

1）Iterator

 

2) 递归

 

3)Visitor模式

 

 

4.转字符串

doc.XMLText

 

5.转XML

doc = DocumentHelper.parseText(String)

 

6.创建XML

Document doc = DocumentHelper.createDocument();

Element root = doc.createElement(root)；

Element author = root.addElement(author).addAttrubate(name, value).addText(Text);

...

 

7.输出

FileWriter writer = new FileWriter（xmlFile）；

writer.write();

 

8.格式输出

 

public void write(Document document) throws IOException {

// 指定文件

XMLWriter writer = new XMLWriter(

new FileWriter( output.xml )

);

writer.write( document );

writer.close();

// 美化格式

OutputFormat format = OutputFormat.createPrettyPrint();

writer = new XMLWriter( System.out, format );

writer.write( document );

// 缩减格式

format = OutputFormat.createCompactFormat();

writer = new XMLWriter( System.out, format );

writer.write( document );

}

 

9.中文乱码

public void createXML(String fileName)
{
    Document doc = DocumentHelper.createDocument();
    Element rootElement = doc.addElement("animal");
    rootElement.addAttribute("name", "汤姆猫");
    Element ageElement = rootElement.addElement("age");
    ageElement.setText("3岁");
    Element colorElement = rootElement.addElement("color");
    colorElement.setText("黄色");
    try
    {
        OutputFormat format = OutputFormat.createPrettyPrint();
        format.setEncoding("UTF-8");
        //XMLWriter xmlWriter = new XMLWriter(new FileWriter(fileName), format);
        XMLWriter xmlWriter = new XMLWriter(new FileOutputStream(fileName), format);
        xmlWriter.write(doc);
        xmlWriter.close();
    }
    catch (Exception e)
    {
        System.out.println(e);
    }
}

在用 dom4j 以 utf8 编码格式生成 xml 文档后，发现该 xml 文档包含中文的部分异常，无法读取。随后被逼无奈，只好使出猥琐招数，直接将要写入 xml 的字符串重新以 utf8 格式编码后再写入 xml：

str = new String(str.getBytes(), "UTF8");

终于，xml 文档异常消除，可以正常读取。然而，其中的中文部分是却乱码，悲了个剧，事情为什么是这个样子呢？

 

终于知道：问题在于 FileWriter 类的滥用，将 FileWriter 改为 FileOutputStream 之后，问题解决。

1 dom4j 中 XMLWriter 对文件的处理过程：

 

public XMLWriter(OutputStream out) throws UnsupportedEncodingException
{
    this.format = DEFAULT_FORMAT;
    this.writer = createWriter(out, format.getEncoding());
    this.autoFlush = true;
    namespaceStack.push(Namespace.NO_NAMESPACE);
}
public XMLWriter(OutputStream out, OutputFormat format) throws UnsupportedEncodingException
{
    this.format = format;
    this.writer = createWriter(out, format.getEncoding());
    this.autoFlush = true;
    namespaceStack.push(Namespace.NO_NAMESPACE);
}
protected Writer createWriter(OutputStream outStream, String encoding) throws UnsupportedEncodingException
{
    return new BufferedWriter( new OutputStreamWriter( outStream, encoding ));
}