如何遍历Java列表数组将对象键值对保存到自己的数组

Question

我想看看是否有可能获取对象的Java列表数组，搜索对象的键值对，并将它们保存到自己的数组中

带有对象的数组

     [
 {
"applicationUserSubscriptionUniqueId": 18639,
"createdByName": "2222",
"updatedDate": "2019-12-02T19:17:45.000+0000",
"applicationsSupported": {
    "appSupportedId": 5,
    "supportAreaId": 123,
    "supportAreas": {
        "applicationId": 123,
    },
    "appSupportedName": "app1"
},
"userSubscriptionInformation": {
    "userSubscribedUniqueId": 18638,
},
"reportSubscriptionId": 18638,

 },
 {
"applicationUserSubscriptionUniqueId": 18638,
"createdByName": "2222",
"updatedDate": "2019-12-02T19:17:45.000+0000",
"applicationsSupported": {
    "appSupportedId": 6,
    "supportAreaId": 123,
    "supportAreas": {
        "applicationId": 123,
    },
    "appSupportedName": "app2"
},
"userSubscriptionInformation": {
    "userSubscribedUniqueId": 18638,
},
"reportSubscriptionId": 18638,

},
{
"applicationUserSubscriptionUniqueId": 18637,
"createdByName": "2222",
"updatedDate": "2019-12-02T19:17:45.000+0000",
"applicationsSupported": {
    "appSupportedId": 15,
    "supportAreaId": 123,
    "supportAreas": {
        "applicationId": 123,
    },
    "appSupportedName": "app3"
},
"userSubscriptionInformation": {
    "userSubscribedUniqueId": 18638,
},
"reportSubscriptionId": 18638,

},
]

代码

public List<ApplicationUserSubscription> findEmailTest() {
int appId = 1;
List<ApplicationUserSubscription> myList = 
applicationUserSubscriptionRepository.findUsersEmailSubscribedToApplication(appId);
System.out.println(myList);

假设我想遍历这个数组，并将所有“appSupportedId”保存到它自己的数组中

NewArray[]=myList。appSupportedId

任何建议或帮助都将不胜感激，谢谢

Answer 1

假设使用的对象具有以下字段，则可以尝试此操作

myList.stream()
      .map(userSub -> userSub.getApplicationsSupported())
      .map(app -> app.getAppSupportedId())
      .toArray(Integer[] :: new);

如果是Map，那么你可以试试

myList.stream()
       .map(userSub -> userSub.get("applicationsSupported"))
       .map(app -> app.get("appSupportedId"))
       .toArray(Integer[] :: new);