随机获取集合里面的某一条数据

获取1个

List<Integer> resList = Arrays.asList(77, 88,99);
Integer integer = resList.get(ThreadLocalRandom.current().nextInt(resList.size()));
System.out.println(integer );

循环100次查看随机数出现的次数

  List<Integer> resList = Arrays.asList(77, 88);Map<Integer, Integer> countMap = new HashMap<>();// 初始化统计Map（确保所有数字都有计数）resList.forEach(num -> countMap.put(num, 0));// 随机选择100次并统计for (int i = 0; i < 100; i++) {Integer randomNum = resList.get(ThreadLocalRandom.current().nextInt(resList.size()));countMap.put(randomNum, countMap.get(randomNum) + 1);}// 打印统计结果System.out.println("随机100次统计结果：");countMap.forEach((num, count) ->System.out.println(num + " 出现次数: " + count));