JAVA随机数

方法一

//可能掉哪些宝物
  List<DragonPub> dragonPubs = DaoCenter.searchDragonDao.findAllDragon(merLevel);
  List<Integer> list = new ArrayList<Integer>();//已经随机到的物品
  int length = 0;//需要随机的总个数
  int sumRate = 0;//所有宝物的总机率
  try {
   sumRate = DaoCenter.searchDragonDao.findRateAllDragons(merLevel);
  } catch (Exception e) {
  }
  int rand=CalculateUtil.calRandomValue(sumRate,sumRate*10);
  if (sumRate != 0){
   int num = rand %sumRate+1;
   while (true){
    for (int i=0;i<dragonPubs.size();i++){
     DragonPub pub = dragonPubs.get(i);
     num -= pub.getDragonPub_rate();
     if (num<=0){//则随机到了该物品

          rand=CalculateUtil.calRandomValue(sumRate,sumRate*10);
       num = rand %sumRate+1;

      if (list.contains(pub.getGoodPub_id())){//不让随机相同的物品
       continue;
      }else{
       length++;
        list.add(pub.getGoodPub_id());//把随机到的物品ID放在list里边避免重复
       
       if (length==dragonRefreshDragonCount){
        break;
       }
      }
      
     }
    }
    if (length == dragonRefreshDragonCount){
     break;
    }
   }
  }

方法二

 

public static import java.util.Random;

int calRandomValue(int minValue, int maxValue) {
  Random random = new Random();
  return minValue + random.nextInt(maxValue - minValue + 1);
 }

参数为：随机的范围