Java 实现大转盘抽奖
需要用到 JAVA中的Random()函数
注意:大转盘抽奖各奖项中奖概率之和为 1。奖品列表中的概率为累加概率,需要按照添加进列表的顺序进行累加,添加顺序不做要求。
实际中使用需要考虑奖品数量限制等业务需求,该代码只是个简单的抽奖demo。
奖品数量限制的话,如果需要保证剩余奖品概率比例不变,需要重新构建奖品列表。
package com.wangbo.choujiang; import java.util.ArrayList; import java.util.List; import java.util.Random; /** * 大转盘抽奖 * @author wangbo * @date 2019-05-22 14:54:47 */ public class Test1 { public static void main(String[] args) { List<Award> awardList = new ArrayList<Award>(); Award award1 = new Award(); award1.setAwardName("手机");//10% award1.setProbability(0.1); awardList.add(award1); Award award2 = new Award(); award2.setAwardName("水杯");//20% award2.setProbability(0.2+0.1);//概率加上上一个奖品的概率(累加) awardList.add(award2); Award award4 = new Award(); award4.setAwardName("鼠标");//10% award4.setProbability(0.1+0.2+0.1); awardList.add(award4); Award award5 = new Award(); award5.setAwardName("谢谢惠顾");//60% award5.setProbability(1d);//最后一个肯定是1 awardList.add(award5); Random random = new Random(); int a = 0,b = 0,c = 0,d = 0; for (int i = 0; i < 10000; i++) { Double userSelect = random.nextDouble();//0.0-1.0的double随机数(不包括1.0) String awardName = duageAward(userSelect, awardList); //信息统计 if ("手机".equals(awardName)) { a++; }else if ("水杯".equals(awardName)) { b++; }else if ("鼠标".equals(awardName)) { c++; }else if ("谢谢惠顾".equals(awardName)){ d++; } } System.out.println("手机 " + a + " 次"); System.out.println("水杯 " + b + " 次"); System.out.println("鼠标 " + c + " 次"); System.out.println("谢谢惠顾 " + d + " 次"); } /** * 选奖品 * @param userSelect * @param awardList * @return */ public static String duageAward(Double userSelect, List<Award> awardList){ for (Award award : awardList) { if(userSelect < award.getProbability()){ return award.getAwardName(); } } return null; } } class Award{ private String awardName; private Double probability; public String getAwardName() { return awardName; } public Double getProbability() { return probability; } public void setAwardName(String awardName) { this.awardName = awardName; } public void setProbability(Double probability) { this.probability = probability; } }
运行结果: