<s:select>錯誤：請求列表鍵「typeSurvey」無法解析

這是我的jsp：<s:select>錯誤：請求列表鍵「typeSurvey」無法解析

<s:form action="InsertSurvey"> 
     <table> 
      <tr> 
       <td> ID Survey: </td><td><s:textfield name="SurveyValues.survey.idtextsurvey"/> </td> 
       <td> Tipo Survey: </td><td><s:select list="typeSurvey"/> </td> 

      </tr> 
     </table> 
    </s:form>

，這是我的動作沒有獲取/設置

public class InsertSurveyAction extends ActionSupport implements Preparable { 

protected SurveyValues surveyValues; 
protected List typeSurvey; 
protected String typeSurveySelected; 

public InsertSurveyAction() { 

} 

@Override 
public String execute() throws Exception { 
    return SUCCESS; 
} 

public void prepare() throws Exception { 
    typeSurvey = new ArrayList(); 
    typeSurvey.add("Multi"); 
    typeSurvey.add("Singolo"); 
}

爲什麼我有這個問題？ *

tag 'select', field 'list': The requested list key 'typeSurvey' could not be resolved as a collection/array/map/enumeration/iterator type. Example: people or people.{name} - [unknown location]

我有struts2的最後一個版本。

來源

2009-11-02 Luigi Candita

<struts> 
<constant name="struts.devMode" value="true"/> 
<constant name="struts.enable.DynamicMethodInvocation" value="false" /> 



<package name="default" extends="struts-default"> 

    <action name="InsertSurvey" class="it.survey.actions.InsertSurveyAction"> 
     <result name="success">/InsertSurvey_step1.jsp</result> 
    </action> 

</package>

來源

2009-11-03 08:58:42