java list的正确remove。避免报java.util.ConcurrentModificationException
list的remove首先要从迭代器中remove
list的正确的remove的办法：

Iterator<StoreFriendLink > it=friendlinks.iterator();
while(it.hasNext()){
StoreFriendLink next=it.next();
if(next.getId().equals(id)){
it.remove();
friendlinks.remove(next);
}
}