用类加载器加载，路径默认为根目录
  Properties properties=new Properties();
  properties.load(this.getClass().getClassLoader().getResourceAsStream(path));

用普通文件加载方式加载，此时是路径为相对路径，用"/"指定
 Properties props = new Properties();
 props.load(new InputStreamReader(new FileInputStream(path), "utf-8"));