src/org/nutz/mvc/adaptor/Params.java
@SuppressWarnings("unchecked")
    public static ParamExtractor makeParamExtractor(HttpServletRequest req,
                                                    Object refer) {
        if (refer != null && Map.class.isAssignableFrom(refer.getClass())) {
            return new MapParamExtractor(req, (Map<String, Object>) refer);
        }
        return new BaseParamExtractor(req);
    }
@SuppressWarnings("unchecked")
    public static ParamExtractor makeParamExtractor(HttpServletRequest req,
                                                    Object refer) {
        if (refer != null && Map.class.isAssignableFrom(refer.getClass())) {
            return new MapParamExtractor(req, (Map<String, Object>) refer);
        }
        return new BaseParamExtractor(req);
    }
构造参数提取器