Java8前后分组类型为Timestamp
Car{
Timestamp DateCreated
}
Map<Timestamp, List<Car>> CarMap = reservePeriodList.stream().collect(groupingBy(Car::getDateCreated));
Car{
Timestamp DateCreated
}
Map<Timestamp, List<Car>> CarMap = reservePeriodList.stream().collect(groupingBy(Car::getDateCreated));