apollo-common/src/main/java/com/ctrip/framework/apollo/common/utils/BeanUtils.java/BeanUtils/aggByKeyToList
class BeanUtils:  @SuppressWarnings("unchecked")
  public static <K, V> Map<K, List<V>> aggByKeyToList(String key, List<?> list) {
    Map<K, List<V>> map = new HashMap<>();
    if (CollectionUtils.isEmpty(list)) {// 防止外面传入空list
      return map;
    }
    try {
      Class<?> clazz = list.get(0).getClass();
      Field field = deepFindField(clazz, key);
      if (field == null) {
          throw new IllegalArgumentException("Could not find the key");
      }
      field.setAccessible(true);
      for (Object o : list) {
        K k = (K) field.get(o);
        map.computeIfAbsent(k, k1 -> new ArrayList<>());
        map.get(k).add((V) o);
      }
    } catch (Exception e) {
      throw new BeanUtilsException(e);
    }
    return map;
  }