英文:
Map and Set in Java- problem with printing
问题
我创建了以下内容，最终希望它像这样写给我：
欧洲
波兰
华沙
克拉科夫
西班牙
巴塞罗那
马德里
怎样做才最简单？
我只能将欧洲分开，其余部分都在同一行
Set<String> cities = new HashSet<>();
Map<String, Set<String>> citiesForCountry = new HashMap<>();
Map<String, Map<String, Set<String>>> countriesForContinent = new HashMap<>();
cities.add("华沙");
cities.add("克拉科夫");
citiesForCountry.put("波兰", cities);
cities = new HashSet<>();
cities.add("巴塞罗那");
cities.add("马德里");
citiesForCountry.put("西班牙", cities);
countriesForContinent.put("欧洲", citiesForCountry);
String space = " ";
System.out.println(countriesForContinent.keySet());
System.out.println(space + countriesForContinent.values());
英文:
I created the following and ultimately I would like it to write to me like this:
Europe
Poland
Warsaw
Cracow
Spain
Barcelona
Madrid
What's the easiest way to do this?
I can only separate Europe, and I have the rest in one line
Set<String> cities=new HashSet<>();
Map<String, Set<String>> citiesForCountry=new HashMap<>();
Map<String, Map<String, Set<String>>> countriesForContinent=new HashMap<>();
cities.add("Warsaw");
cities.add("Cracow");
citiesForCountry.put("Poland", cities);
cities=new HashSet<>();
cities.add("Barcelona");
cities.add("Madrid");
citiesForCountry.put("Spain", cities);
countriesForContinent.put("Europe", citiesForCountry);
String space= " ";
System.out.println(countriesForContinent.keySet());
System.out.println(space+ countriesForContinent.values());
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