java利用dom4j来操作xml文件

使用dom4j操作xml文件可以参考dom4j的api文档。

 

1、parsing XML 解析xml文件

SAXReader reader = new SAXReader();
File file =new File("xx.xml");
Document document = reader.read(file);

2、获取根元素

Element root = document.getRootElement();

3、获取所有的元素、获取某个特定的元素、获取根元素的属性

// iterate through child elements of root
        for ( Iterator i = root.elementIterator(); i.hasNext(); ) {
            Element element = (Element) i.next();
            // do something
        }

        // iterate through child elements of root with element name "foo"
        for ( Iterator i = root.elementIterator( "foo" ); i.hasNext(); ) {
            Element foo = (Element) i.next();
            // do something
        }

        // iterate through attributes of root 
        for ( Iterator i = root.attributeIterator(); i.hasNext(); ) {
            Attribute attribute = (Attribute) i.next();
            // do something
        }

 4、将document写入文件

//prepare an output format,which has new line .打印（显示）出来有格式
OutputFormat format = OutputFormat.createPrettyPrint();
format.setIndentSize(4);
		
//
OutputStream os = new FileOutputStream(fileName);

//output stream ( where to output )and format (how to output)
XMLWriter writer = new XMLWriter(os,format);
	
//output content( what to be output)---document
writer.write(document);

writer.close();

 

 使用例子

1、在xml文件中增加element

      步骤：1、open the document and get the rootDocument;

               2、construct an element ;

               3、append the newly element to the root element;

               4、update the count of the root element;此处是更新根元素的count属性，如果没有这个属性则不需要更新，count属性存储element 的个数。

               5、save the document into the file.