权重随机算法Java实现

权重随机算法在抽奖，资源调度等系统中应用还是比较广泛的，一个简单的按照权重来随机的实现，权重为几个随机对象(分类)的命中的比例，权重设置越高命中越容易，之和可以不等于100；

简单实现代码如下：

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importjava.util.ArrayList;  
importjava.util.List;  
importjava.util.Random;  
   
publicclass WeightRandom {  
    staticList<WeightCategory>  categorys = newArrayList<WeightCategory>();  
    privatestatic Random random = newRandom();  
       
    publicstatic void initData() {  
        WeightCategory wc1 = newWeightCategory("A",60); 
        WeightCategory wc2 = newWeightCategory("B",20); 
        WeightCategory wc3 = newWeightCategory("C",20); 
        categorys.add(wc1); 
        categorys.add(wc2); 
        categorys.add(wc3); 
    } 
   
    publicstatic void main(String[] args) {  
          initData(); 
          Integer weightSum = 0; 
          for(WeightCategory wc : categorys) {  
              weightSum += wc.getWeight();  
          } 
   
          if(weightSum <= 0) {  
           System.err.println("Error: weightSum=" + weightSum.toString());  
           return; 
          } 
          Integer n = random.nextInt(weightSum); // n in [0, weightSum)  
          Integer m = 0; 
          for(WeightCategory wc : categorys) {  
               if(m <= n && n < m + wc.getWeight()) {  
                 System.out.println("This Random Category is "+wc.getCategory()); 
                 break; 
               } 
               m += wc.getWeight();  
          } 
   
             
    } 
   
} 
   
classWeightCategory {  
    privateString category;  
    privateInteger weight;  
       
   
    publicWeightCategory() {  
        super(); 
    } 
   
    publicWeightCategory(String category, Integer weight) {  
        super(); 
        this.setCategory(category); 
        this.setWeight(weight); 
    } 
   
   
    publicInteger getWeight() {  
        returnweight;  
    } 
   
    publicvoid setWeight(Integer weight) {  
        this.weight = weight;  
    } 
   
    publicString getCategory() {  
        returncategory;  
    } 
   
    publicvoid setCategory(String category) {  
        this.category = category;  
    } 
}