求助：顺序不正确

Enumeration paramNames = request.getParameterNames();
if(paramNames!=null){
    while(paramNames.hasMoreElements()){
    String paramName = (String) paramNames.nextElement();
    String paramValue=request.getParameter(paramName);
    out.println(paramValue);
    }
}
比如传入参数的顺序为 A B C D
则打印顺序为  A D C B
这是怎么回事啊