package Collections_package; import java.util.ArrayList; import java.util.Collections; public class Collections_demo1 { public static void main(String[] args) { /* public static boolean addAll (Collection c, T...elements) 批量添加元素 public static void shuffle (List list) 打乱List集合元素的顺序 */ //addAll 批量添加元素 //1、创建集合对象 ArrayList list=new ArrayList<>(); //2、批量添加元素 Collections.addAll(list,"abc","abc","bcd","edf","asdf"); //3、打印集合 System.out.println(list); //4、shuffle 打乱 Collections.shuffle(list); System.out.println(list); } }