System.out输出重定向

dom4j格式化输出为String作例子

	/**
	 * 打印文档，String输出
	 * 
	 * @param doc
	 * @param encoding
	 */
	public static String printString(Document doc, String encoding) {
		if (encoding == null)// 默认为UTF-8编码
		{
			encoding = "UTF-8";
		}
		String docStr = null;
		OutputFormat format = OutputFormat.createPrettyPrint();
		format.setEncoding(encoding);
		PrintStream defaultOut = System.out;// 保存原来的sysout
		ByteArrayOutputStream out = new ByteArrayOutputStream();
		System.setOut(new PrintStream(out)); // 重定向sysout

		XMLWriter systemWriter;
		try {
			systemWriter = new XMLWriter(System.out, format);
			systemWriter.write(doc);

			systemWriter.close();

			// 屏幕输出
			System.setOut(defaultOut); // 恢复原来的sysout
			docStr = new String(out.toByteArray(), encoding);// 生成String串

		} catch (UnsupportedEncodingException e) {
			System.err.println(e);
		} catch (IOException e) {
			System.err.println(e);
		}
		return docStr;
	}