1 package com.pang.jihe_demo;
 2 
 3 import java.util.ArrayList;
 4 import java.util.Arrays;
 5 import java.util.List;
 6 
 7 public class Demo01 {
 8     public static void main(String[] args) {
 9         //集合转数组,集合中只可以装引用数据类型
10         ArrayList<Integer> list = new ArrayList<>();
11         list.add(12);
12         list.add(11);
13         list.add(9);
14         Object[] array = list.toArray();
15         System.out.println(Arrays.toString(array));
16         //数组转集合
17         Integer[] arr = {12,1,23,4,55};
18         List<Integer> asList = Arrays.asList(arr);
19         System.out.println(asList);
20     }
21 }