public static void setRandom(int min, int max, int n, HashSet<Integer> set) {
Random random = new Random();
for (int i = 0; i < n; i++) {
int ranInt = random.nextInt(max - min + 1);
if(!set.add(ranInt)){
i--;
}
}
}
原文：http://www.cnblogs.com/qj4d/p/6640472.html