直接上代码
ArrayList 实现
public class nov_23 {
public static void main(String[] args) {
ArrayList list = new ArrayList();
for (int i=0 ;i<20;i++){
list.add(i+1);
}
Random r = new Random();
System.out.println(list);
for (int j =0;j<10;j++){
int re=r.nextInt(list.size());
int rand= (int) list.get(re);
list.remove(re);
System.out.println(rand);
}
}}
HashSet 实现
public class nov_23 {
public static void main(String[] args) {
HashSet set = new HashSet();
Random r = new Random();
while (set.size()<10){
set.add(r.nextInt(20)+1);
}
Iterator i = set.iterator();
while(i.hasNext()){
Object j=i.next();
System.out.println(j);
}}}