code: public void loadPropertiesFromPath(String rootPath) {
  		if (StringUtils.isNotBlank(rootPath)) {
  			LogUtil.writeLog("从路径读取配置文件: " + rootPath+File.separator+FILE_NAME);
  			File file = new File(rootPath + File.separator + FILE_NAME);
  			InputStream in = null;
  			if (file.exists()) {
  				try {
  					in = new FileInputStream(file);
  					properties = new Properties();
  					properties.load(in);
  					loadProperties(properties);
  				} catch (FileNotFoundException e) {
  					LogUtil.writeErrorLog(e.getMessage(), e);
  				} catch (IOException e) {
  					LogUtil.writeErrorLog(e.getMessage(), e);
  				} finally {
  					if (null != in) {
  						try {
  							in.close();
  						} catch (IOException e) {
  							LogUtil.writeErrorLog(e.getMessage(), e);
  						}
  					}
  				}
  			} else {
  				// 由于此时可能还没有完成LOG的加载，因此采用标准输出来打印日志信息
  				LogUtil.writeErrorLog(rootPath + FILE_NAME + "不存在,加载参数失败");
  			}
  		} else {
  			loadPropertiesFromSrc();
  		}
  
  	}
docs: 从properties文件加载
  
  @param rootPath
  不包含文件名的目录.