java / map /collection

Question

Cześć,

mam taki obiekt json:

"code":200,
"description":"OK.",
"data":[
{
"categoryId":1,
"remoteId":0,
"categoryName":"Soccer",
"level":1,
"parentCategory":0,
"sportId":1,
"eventsCount":258,
"sortOrder":0,
"treatAsSport":1,
"categoryFlag":"null"
},
{
"categoryId":2,
"remoteId":0,
"categoryName":"Basketball",
"level":1,
"parentCategory":0,
"sportId":2,
"eventsCount":7,
"sortOrder":0,
"treatAsSport":2,
"categoryFlag":"null"
},
{
"categoryId":12,
"remoteId":0,
"categoryName":"Rugby",
"level":1,
"parentCategory":0,
"sportId":12,
"eventsCount":1,
"sortOrder":0,
"treatAsSport":12,
"categoryFlag":"null"
},
{
"categoryId":21,
"remoteId":0,
"categoryName":"Cricket",
"level":1,
"parentCategory":0,
"sportId":21,
"eventsCount":12,
"sortOrder":0,
"treatAsSport":21,
"categoryFlag":"null"
},
{
"categoryId":201,
"remoteId":0,
"categoryName":"England",
"level":2,
"parentCategory":1,
"sportId":1,
"eventsCount":78,
"sortOrder":0,
"treatAsSport":1,
"categoryFlag":"null"
},
{
"categoryId":204,
"remoteId":0,
"categoryName":"Spain",
"level":2,
"parentCategory":1,
"sportId":1,
"eventsCount":29,
"sortOrder":0,
"treatAsSport":1,
"categoryFlag":"null"
},
{
"categoryId":233,
"remoteId":0,
"categoryName":"Germany",
"level":2,
"parentCategory":1,
"sportId":1,
"eventsCount":18,
"sortOrder":0,
"treatAsSport":1,
"categoryFlag":"null"
},
{
"categoryId":245,
"remoteId":0,
"categoryName":"Italy",
"level":2,
"parentCategory":1,
"sportId":1,
"eventsCount":28,
"sortOrder":0,
"treatAsSport":1,
"categoryFlag":"null"
},
{
"categoryId":257,
"remoteId":0,
"categoryName":"France",
"level":2,
"parentCategory":1,
"sportId":1,
"eventsCount":45,
"sortOrder":0,
"treatAsSport":1,
"categoryFlag":"null"
},

 

		LinkedHashMap<Integer, ActiveCategoryModel> categories = marketRequestManager
				.getCategories(languageTools.getLanguageCode(language));
		Collection<ActiveCategoryModel> categoriesSet = null;

			for (ActiveCategoryModel test : categories.values()) {
				s = test.getCategoryName();}

jak moge posortować wszystko na podstawie categoryname i zwrocic calość nie tylko liste z categoryname?

Answer 1

Da się to posortować streamami. Identyczny problem tutaj: https://stackoverflow.com/a/23846961

Gdzie komparatorem bedzie:

Comparator.comparing(ActiveCategoryModel::getCategoryName)

 

Comments

dasz rade napisal mi troche wiecej kodu? bo niestety nie jestem w stanie sie w tym ogarnac ...;/

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jaka wersja javy?

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1.8

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@RafalS,

The method sort(Comparator<? super Map.Entry<Integer,ActiveCategoryModel>>) in the type List<Map.Entry<Integer,ActiveCategoryModel>> is not applicable for the arguments (Comparator<Map.Entry<Object,Comparable<? super Comparable<? super V>>>>)

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Szczerze troszke nie wiem z czym masz problem. Bo mając ten przykład z SO:

Map<K,V> topTen =
    map.entrySet().stream()
       .sorted(Map.Entry.comparingByValue(Comparator.reverseOrder()))
       .limit(10)
       .collect(Collectors.toMap(
          Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));

potrzebujesz jedynie wywalic limit i zamiast Comparator.reverseOrder wstawic:

Comparator.comparing(ActiveCategoryModel::getCategoryName)

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dzieki