src/org/nutz/lang/util/NutMap.java
@Override
    @SuppressWarnings("unchecked")
    public NutMap addv2(String key, Object value) {
        List<Object> list = (List<Object>) get(key);
        if (null == list) {
            list = new LinkedList<Object>();
            put(key, list);
        }
        list.add(value);
        return this;
    }
@Override
    @SuppressWarnings("unchecked")
    public NutMap addv2(String key, Object value) {
        List<Object> list = (List<Object>) get(key);
        if (null == list) {
            list = new LinkedList<Object>();
            put(key, list);
        }
        list.add(value);
        return this;
    }
为 Map 增加一个名值对。强制设置为一个列表，如果有同名则合并

@param key
@param value