guava之Multimap

键可重复的map

Multimap<Integer,String> mp = HashMultimap.create();mp.put(1,"a");mp.put(1,"b");mp.put(1,"c");mp.put(1,"c");mp.put(2,"d");Collection<String> c = mp.get(1);System.out.println(c.toString());System.out.println(mp.size());

结果:

[a, b, c]
4