java stream()简单使用

 List<T> list = new Arraylist();
        Map<Long, T> bizAreasMap = list.stream().collect(Collectors.toMap(T::T.getID(), r -> r, (key1, key2) -> key2));

List<T> lists = list.stream().filter(r -> r.getType() == 1).collect(Collectors.toList());

 List<TT> lists = list.stream().map(a -> {
            TT tt= new TT();
            BeanUtils.copyProperties(a, tt);
            return tt;
        }).collect(Collectors.toList());

Map<Long, List<T>> t= list.stream().collect(
                Collectors.groupingBy(T::getId));