Java笔记第一弹、Stream常用方法

Java笔记第一弹、Stream常用方法

//list对象取某个字段
        List vehicleIds = list.stream().map(OcCarebasePO::getVehicleId).collect(Collectors.toList());
        //list对象转map-重复取后者
        Map map = list.getResult().stream().collect(Collectors.toMap(Vehicle3VO::getVehicleID, Vehicle3VO::getVehicleBrand(), (a, b) -> b));
        //list对象转map-重复合并为list
        Map> map = list.stream().collect(Collectors.groupingBy(OcCareRulePO::getVehicleBrandDic));
        // 根据name去重
        List unique = persons.stream().collect(Collectors.collectingAndThen(Collectors.toCollection(() -> new TreeSet<>(Comparator.comparing(Person::getName))), ArrayList::new));
        //过滤空值
        List repairFactoryIds = list.stream().filter(l -> Objects.nonNull(l.getRepairFactoryId())).collect(Collectors.toList());