java抽奖程序代码_java抽奖系统的设计

java抽奖程序代码_java抽奖系统的设计 奖品类：抽奖逻辑：测试类：测试结果：商品类：package org.plusgroup.modules.app.controller.vo;import io.swagger.annotations.ApiModelProperty;import lombok.Data;import java.util.ArrayList;import java.util.List;/** * @author Administrator * @desc 奖品VO * @date 2021/7/9 14:30 */@Datapublic class PrizeVo { @ApiModelProperty("奖品ID") private Integer id; @ApiModelProperty("奖品名称") private String name; @ApiModelProperty("奖品编号") private String code; @ApiModelProperty("中奖概率") private Double rate; public PrizeVo(Integer id, String name, String code, Double rate) { this.id = id; this.name = name; this.code = code; this.rate = rate; } public PrizeVo() { } /** * 初始化奖品 * @return List */ public static List<PrizeVo> init(){ List<PrizeVo> list = new ArrayList<>(); list.add(new PrizeVo(10, "文档打印券", "P1", 0.2d)); list.add(new PrizeVo(20, "照片打印券", "P2", 0.5d)); list.add(new PrizeVo(30, "5元代金券", "P3", 0.1d)); list.add(new PrizeVo(40, "谢谢参与", "P4", 0.2d)); return list; }}测试类：package org.plusgroup.modules.admin.service;import org.plusgroup.modules.app.controller.vo.PrizeVo;import org.springframework.util.CollectionUtils;import java.util.*;/** * @author Administrator * @desc * @date 2021/7/9 14:43 */public class IntegralLogTest { public static void main(String [] args){ //奖品中奖概率集合 List<Double> rates = new ArrayList<>(); //将每个奖品的概率放入概率集合 List<PrizeVo> list = PrizeVo.init(); for(PrizeVo prizeVo : list){ rates.add(prizeVo.getRate()); } System.out.println("本次中奖商品下标:" +luckDraw(rates)); // 统计每种商品中奖次数 Map<Integer, Integer> countMap = new HashMap<>(); double num = 10000; //测试次数 for (int i = 0; i < num; i++) { int key = luckDraw(rates); Integer value = countMap.get(key); countMap.put(key, value == null ? 1 : value + 1); } for (Map.Entry<Integer, Integer> entry : countMap.entrySet()) { System.out.println(list.get(entry.getKey()) + ", 命中次数=" + entry.getValue() + ", 实际概率=" + entry.getValue() / num); } } /** * 抽奖逻辑 * @param rates 概率集合 * @return int */ public static int luckDraw(List<Double> rates) { if (CollectionUtils.isEmpty(rates)) { return -1; } //计算总概率，概率集合累加 double totalRate = 0d; for (double rate : rates) { totalRate += rate; } // 每个奖品在总概率基础下的概率 List<Double> sortRates = new ArrayList<>(); double everyRate = 0d; for (double rate : rates) { everyRate += rate; sortRates.add(everyRate / totalRate); } // 根据区块值来获取抽取到的物品索引 double nextDouble = Math.random(); sortRates.add(nextDouble); Collections.sort(sortRates); return sortRates.indexOf(nextDouble); }}