找了好久才找到的。。。

Action

 Map<String,List<String>> kindsMap
 = new HashMap<String,List<String>>();

 List<String> aList = new ArrayList<String>();
 aList.add("a1");
 aList.add("a2");

  List<String> bList = new ArrayList<String>();
  bList.add("b1");
  bList.add("b2");


 kindsMap.put("a",aList);
 kindsMap.pu t("b", bList);

ftl

<#list kindsMap?keys as mKey>

    ${mKey}
    <#assign item = kindsMap[mKey]>
     <#list item as itemValue>

         ${itemValue}
     </#list>
   </#list>



如果list里还有实体 可直接 ${itemValue.属性}