collections

public class CollectionsDemo1 {
    public static void main(String[] args) {
        //collections是集合的工具类,不是集合
        /*
        public static <T> boolean addAll(Collection<T> c,T...element) 批量添加元素
        public static void shuffle(List<?> list) 打乱list集合元素的顺序
         */

        //1.创建集合
        ArrayList<String> list = new ArrayList<>();
        //2.批量添加元素
        Collections.addAll(list, "haha", "xiangxiang", "baby", "abc", "shd", "lala", "xixi");
        //打印
        System.out.println(list);
        //3.打乱顺序
        Collections.shuffle(list);
        System.out.println(list);
        System.out.println("---------------------");
        //排序
        Collections.sort(list);
        System.out.println(list);
        //按指定方法排序
        Collections.sort(list, (o1, o2) -> {
                    return o1.length() - o2.length();
                }
        );
        System.out.println(list);

        //查找元素
        int i = Collections.binarySearch(list, "haha");
        System.out.println(i);
        //拷贝集合
        ArrayList<String> list1=new ArrayList<>(Collections.nCopies(list.size(),null));
        Collections.copy(list1,list);
        System.out.println(list1);
        //填充集合
        //Collections.fill(list,"haha");

        //获取最大最小值
        String max = Collections.max(list);
        System.out.println(max);
        String min=Collections.min(list);
        System.out.println(min);
        //交换集合指定位置的元素
        Collections.swap(list,2,5);
        System.out.println(list);
    }
}