map.put(3, 5);
System.out.println(map.get(2));
System.out.println(map.containsKey(2));
System.out.println(map.containsValue(5));
System.out.println(map.keySet());
System.out.println(map.values());
原文：http://www.cnblogs.com/lili1015/p/4648701.html