code: public static String getClassRootPath(Class<?> c) {
  		String strClassPathName = getClassPathName(c);
  
  		ClassLoader cl = c.getClassLoader();
  		if (cl == null)
  			return null;
  
  		URL urlClass = cl.getResource(strClassPathName);
  		if (urlClass == null)
  			return null;
  
  		String strUrl = urlClass.toString();
  		return strUrl.substring(0, strUrl.lastIndexOf(strClassPathName));
  	}
docs: 返回指定类的Class Loader用于加载该类的Class Path。返回的字符串以/结尾