解决collection调用removeAll()移除不了不同引用同值对象的问题
http://blog.csdn.net/tavor/article/details/2502350
关于java中List的removeAll()方法删除大量数据时的效率问题
http://www.iteye.com/problems/80120
public static List removeAll(List a,List b){
LinkedList c=new LinkedList(a);//大集合用LinkedList
HashSet s=new HashSet(b);//小集合用HashSet
Iterator iter=c.iter;
while(iter.hasNext()){
if(s.contains(iter.next()){
iter.remove();
}
}
return c;
}