比对两个集合的差异,并返回差异数据(集合)-可以是对象与基本类型

用map性能高些

private <T> List<T> getNewList(List<T> allList, List<T> existList) {

    Map<T, Integer> map = new HashMap<>(16);
    for (int i = 0; i < allList.size(); i++) {
      map.put(allList.get(i), i);
    }

    for (int i = 0; i < existList.size(); i++) {
      Integer pos = map.get(existList.get(i));
      if (pos == null) {
        continue;
      }
      allList.set(pos, null);
    }

    for (int i = allList.size() - 1; i >= 0; i--) {
      if (allList.get(i) == null) {
        allList.remove(i);
      }
    }
    return allList;
  }