java对象list使用stream根据某一个属性转换成map的3种方式举例

List<Person> personList = ... // 假设这是一个Person对象列表
Map<String, Person> personMap = personList.stream()
        .collect(Collectors.toMap(Person::getName, Function.identity()));

List<Person> personList = ... // 假设这是一个Person对象列表
Map<Person, String> personMap = personList.stream()
        .collect(Collectors.toMap(Function.identity(), Person::getAddress));

List<Person> personList = ... // 假设这是一个Person对象列表
Map<String, String> personMap = personList.stream()
        .collect(Collectors.toMap(Person::getName, Person::getAddress));

    List<ResourcesInfoCapacityExcel> resourceInfoExcels = resourcesInfoCapacities.stream().map(
                todo -> new ResourcesInfoCapacityExcel(todo.getModelName(), todo.getExistingCapacity(), todo.getForecastWorkload(), todo.getDifferenceWorkload(), todo.getMonth()
                )).collect(Collectors.toList());

  Map<String, Double> foreWorkLoad = new HashMap<>();
foreWorkLoad.merge(key, resourcesWorkloadCalculate1.getWorkLoad(), (a, b) -> a + b);

 Map<String, List<ResourcesInfo>> resourcesInfosListMap =new HashMap<>();
        for (ResourcesInfo resourcesInfo:
        resourcesInfos) {
            String key=resourcesInfo.getModel() + "," + workDateMap.get(resourcesInfo.getMonth());

            List<ResourcesInfo>  moduleRanks = resourcesInfos.stream()
                    .filter(e -> resourcesInfo.getModel() == null || resourcesInfo.getModel().equals(e.getModel())
                    ).filter(e -> resourcesInfo.getMonth() == null || resourcesInfo.getMonth().equals(e.getMonth())
            ).collect(Collectors.toList());
            if (resourcesInfosListMap.get(key)==null){
                resourcesInfosListMap.put(key,moduleRanks);
            }else {
                moduleRanks.addAll(resourcesInfosListMap.get(key));
                resourcesInfosListMap.put(key,moduleRanks);
            }
        }