java8 stream对list进行多个字段同时分组,并且给对象赋值

必须重写实体类的hashcode方法和equals方法
实现
根据ABC来分组 拿到开始时间小于当前时间的最大对象 并且给对象的D属性赋值

Map<String, List<Charging>> collect = chargings.stream()
                .filter(charging -> System.currentTimeMillis() > charging.getStartTime().getTime())
                .collect(
                        Collectors.groupingBy(charging -> charging.getA() + charging.getB() + charging.getC(),
                                Collectors.collectingAndThen(Collectors.toList(),
                                        x -> {
                                            x.stream().collect(Collectors.maxBy(Comparator.comparing(TCharging::getStartTime)))
                                                    .ifPresent(charging -> charging.setD("1"));
                                            return x;
                                        })));