java - 制作一个 Hashmap，其键是字符串，值是 HashSets

Question

尝试使用字符串键和哈希集值创建 HashMap 。我希望哈希集都是整数

Set<String> numbersSet = new HashSet<Integer>();

// won't work:
HashMap<String, numberSet> database = new HashMap<String, numberSet>();//error - "( or [ expected"

//Also won't work. If it did, how can even I add to the set inside this hashMap?
HashMap<String, HashSet<Integer>> database = new HashMap<String, HashSet<Integer>>(); //error-incompatible types

Answer 1

HashMap<String, HashSet<Integer>> database = new HashMap<String, HashSet<Integer>>();

对我有用。

顺便说一句，如果您使用的是 JDK 1.7，您可以使用:

HashMap<String, HashSet<Integer>> mymap = new HashMap<>();