code: public static BufferedReader getReader(Reader reader) {
  		if (null == reader) {
  			return null;
  		}
  
  		return (reader instanceof BufferedReader) ? (BufferedReader) reader : new BufferedReader(reader);
  	}
docs: 获得{@link BufferedReader}<br>
  如果是{@link BufferedReader}强转返回，否则新建。如果提供的Reader为null返回null
  
  @param reader 普通Reader，如果为null返回null
  @return {@link BufferedReader} or null
  @since 3.0.9