code: public void render(Map<?, ?> data, File file) {
  		FileOutputStream fos = null;
  		try {
  			fos = new FileOutputStream(file);
  			render(data, fos);
  		} catch (FileNotFoundException e) {
  			throw new RuntimeException(e);
  		} finally {
  			if (fos != null) {
  				try {fos.close();} catch (IOException e) {e.printStackTrace(System.err);}
  			}
  		}
  	}
docs: 渲染到 File 中去
  适用于代码生成器类似应用场景