import java.util.Map.Entry;
       
     private static Map oldvote=new HashMap();
           ...............................
         ModelAndView mav = new ModelAndView();
        String voteid = ServletRequestUtils.getRequiredStringParameter(request,
                "voteid");
        String ip = ServletRequestUtils.getStringParameter(request, "ip");

        //遍历HasMap
        Boolean isoldvote=false;
        Iterator it=oldvote.entrySet().iterator();
        while(it.hasNext()){
            Entry  entry=(Entry) it.next();
            Object key=entry.getKey();
            Object value=entry.getValue();
            if(key.equals(voteid)&&value.equals(ip)){
             isoldvote=true;
             break;
            }
        }

        if (isoldvote) {
         ...............................