docs: private static void addClass(Set<Class<?>> classSet, String packagePath, String packageName) {
          File[] files = new File(packagePath)
                  .listFiles(file -> file.isFile() && file.getName().endsWith(".class") || file.isDirectory());
          if (ArrayUtils.isEmpty(files)) {
              return;
          }
          for (File file : files) {
              String fileName = file.getName();
              // 是指定的文件 就获取到全限定类名 然后装载它
              if (file.isFile()) {
                  String className = fileName.substring(0, fileName.lastIndexOf("."));
                  if (StringUtils.isNotBlank(packageName)) {
                      className = packageName + "." + className;
                  }
                  doAddClass(classSet, className);
              } else {
                  String subPackagePath = fileName;
                  if (StringUtils.isNotBlank(subPackagePath)) {
                      subPackagePath = packagePath + "/" + subPackagePath;
                  }
                  String subPackageName = fileName;
                  if (StringUtils.isNotBlank(packageName)) {
                      subPackageName = packageName + "." + subPackageName;
                  }
                  addClass(classSet, subPackagePath, subPackageName);
              }
          }
      }