JAVA 随机选出MAP中的键

 

1. Map<Integer, Integer> map = new HashMap<Integer, Integer>();

2. map.put(33, 333);

3. map.put(123, 1234);

4. map.put(321, 4321);

5. map.put(555,5555);

6. Integer[] keys = map.keySet().toArray(new Integer[0]);

7. Random random = new Random();

8. Integer randomKey = keys[random.nextInt(keys.length)];

9. System.out.println(randomKey);