依照权重随机抽取元素

[代码] [Java]代码 import java.math.BigDecimal;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.collections.Bag;
import org.apache.commons.collections.bag.TreeBag;
/**
http://www.fpjinan.com/linked/20130223.do; * 依照权重随机抽取元素
* @author heyang
*
*/
public class RandomUtil {
/**
* 依据指定的样本数组和样本-权重映射随机抽取一个元素
* @param elementArray 样本数组
* @param weightMap 样本-权重映射
* @return
* @throws Exception
*/
public static Object randomByWeight(Object[] elementArray,Map weightMap) throws Exception{
if(elementArray==null||elementArray.length==0){
throw new Exception("ElementArray must not be empty!");
}
if(weightMap==null|| weightMap.isEmpty()){
throw new Exception("WeightMap must not be empty!");
}
int[] weightArray = new int[elementArray.length 1];
Object[] tempElementArray = new Object[elementArray.length];
for(int i=0;i desArray[middle]