package Case_demo2; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.Random; public class Test2 { public static void main(String[] args) { /* 班级里有N个学生 要求: 70%的概率随机到男生 30%的概率随机到女生 "范闲", "范建", "范统", "杜子腾", "朱合泛", "侯笼藤", "朱益群", "朱穆朗玛峰" "杜琦燕", "袁明媛", "李猜", "田密密" */ //1、创建集合 ArrayList list = new ArrayList<>(); //2、添加数据 Collections.addAll(list, 1, 1, 1, 1, 1, 1, 1); Collections.addAll(list, 0, 0, 0); //3、打乱集合中的数据 Collections.shuffle(list); //4、从list集合中随机抽取0或者1 Random r = new Random(); int index = r.nextInt(list.size()); int number = list.get(index); System.out.println(number); //5、创建两个集合分别存储男生和女生的名字 ArrayList boyList = new ArrayList<>(); ArrayList girlList = new ArrayList<>(); Collections.addAll(boyList, "范闲", "范建", "范统", "杜子腾", "朱合泛", "侯笼藤", "朱益群", "朱穆朗玛峰"); Collections.addAll(girlList, "杜琦燕", "袁明媛", "李猜", "田密密"); //6、判断此时是从boyList里面抽取还是从girlList里面抽取 if (number == 1) { //boyList int boyIndex = r.nextInt(boyList.size()); String name = boyList.get(boyIndex); System.out.println(name); } else { //girlList int girlIndex = r.nextInt(girlList.size()); String name = girlList.get(girlIndex); System.out.println(name); } } }