Java list 隨機取數據

作用：從list中隨機取出n條數據

 

用法

List<HomeMemberDTO> memberListByiDs = memberService.getMemberListByiDs(arrayList);
//隨機取n條數據
map.put("exclusiveListT",ListUtils.getRandomList(memberListByiDs,2));

 

工具類

package com.home.app.common.utils;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;

/**
 * list 工具類
 */
public class ListUtils {

    /**
    * @Description list 隨機取數據
    * @params     list    list集合
    *           num     隨機取多少條
    **/
    public static List getRandomList(List list, int num) {
        List olist = new ArrayList<>();
        if (list.size() <= num) {
            return list;
        } else {
            Random random = new Random();
            for (int i = 0 ;i<num;i++){
                int intRandom = random.nextInt(list.size() - 1);
                olist.add(list.get(intRandom));
                list.remove(list.get(intRandom));
            }
            return olist;
        }
    }
}