将值放入内部 Map

Question

我有一个看起来像这样的 ConcurrentHashMap：private Map<String,Map<String,Set<PublicKey>>> instancePairs = new ConcurrentHashMap<>();以及一个应该填充此哈希图的方法。但我无法弄清楚如何将值放入地图中目前我有：instancePairs.putIfAbsent(inMemoryInstance.getUsername(), inMemoryInstance.getId() , publicKeySet);Intellij Idea 给我这个错误：

Answer 1

正如“DDovzhenko”所提到的，你需要按照以下几行做一些事情。

//Get the map containing the ID as keys, if it doesn't exist, then create one.

Map mapValuesForName = instancePairs.getOrDefault(inMemoryInstance.getUsername(), new ConcurrentHashMap<String,Set<PublicKey>>());

//Put the publicKeySet based on the Id.

mapValuesForName.putIfAbsent(inMemoryInstance.getId(), publicKeySet);

//Store the potentially changed/new value back in original map.

instancePairs.put(mapValuesForName);