Freemarker和hashmap。我如何获得键值

I have a hash map as below

我有一个哈希映射如下

HashMap<String, String> map = new HashMap<String, String>();
map.put("one", "1");
map.put("two", "2");
map.put("three", "3");

Map root = new HashMap();
root.put("hello", map);
HashM