Java实现按比抽奖功能

 /**
   * 按比例随机抽取一项
   * @param list 奖品列表
   * @return 类型值
   */
  public static String ratioExtract(List list) {
    //非空判断
    if (list==null || list.size()<1) {
      return null;
    }
    //占比之和
    double sum=0.00;
    //分段数组(20,30,60)
    double[] subArray=new double[list.size()+1];
    //将概率分段
    for (int i = 0; i =subArray[i] && rand

import lombok.Data;
import org.apache.commons.lang.math.RandomUtils;

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

/**
 * @Description: 抽奖工具类
 * @author: xiake
 * @Date: 2020/1/5 13:23
 * @ModifiedDate：2020/1/5 13:23
 * @Copyright: miaoxaike.com
 */
public class PrizeMathRandom {

  /**
   * 按比例随机抽取一项
   * @param fieldArray 类型值数组
   * @param proportions 与类型值对应 的占比值
   * @return 类型值
   */
  public static String ratioExtract(String[] fieldArray,double[] proportions) {
    //判断两个数组长度是否相等
    if(fieldArray.length!=proportions.length) {
      return "两数组长度不相等,无法执行";
    }

    //占比之和
    double sum=0.00;
    //分段数组(20,30,60)
    double[] subArray=new double[proportions.length+1];
    //将概率分段
    for (int i = 0; i =subArray[i] && rand list) {
    //非空判断
    if (list==null || list.size()<1) {
      return null;
    }
    //占比之和
    double sum=0.00;
    //分段数组(20,30,60)
    double[] subArray=new double[list.size()+1];
    //将概率分段
    for (int i = 0; i =subArray[i] && rand

public static void main(String[] args) {
    //初始化奖品信息
    List prizeList=new ArrayList<>();
    prizeList.add(new Prize("一等奖",1,1));
    prizeList.add(new Prize("二等奖",3,4));
    prizeList.add(new Prize("三等奖",6,5));

    for (int i = 0; i <12; i++) {
      Prize prize = ratioExtract(prizeList);
      if (prize!=null){
        System.out.println("第"+(i+1)+"次,抽中 "+prize.getPrizeName()+" 剩余奖品数量="+prize.getPrizeCount());
      }else {
        System.out.println("第"+(i+1)+"次,奖品已抽完");
      }

    }
  }