DOM4J格式化XML

/**
	 * @Title			formatXML
	 * @Description 	格式化XML
	 * @param retStr	XML字符串
	 * @return
	 * @throws Exception    
	 * @return		String
	 * @throws
	 */
	public static String formatXML(String retStr) throws Exception {
		String res = null;
		Document doc = null;
		try {
			doc = DocumentHelper.parseText(retStr);
		} catch (DocumentException e) {
			e.printStackTrace();
			return null;
		}
//		Element root = doc.getRootElement();
		//格式化XML
		OutputFormat format = new OutputFormat();
		//设置元素是否有子节点都输出
		format.setExpandEmptyElements(true);
		//设置不输出XML声明
		format.setSuppressDeclaration(true);
		
		OutputStream outputStream = new ByteArrayOutputStream();
		XMLWriter writer = new XMLWriter(outputStream, format);
		writer.write(doc);
		writer.close();
		res = outputStream.toString();
		return res;
	}