Servlets 再次调用相同的操作

当我第一次启动操作时，没有显示任何错误，但在第一次请求后，我得到了这个错误

我在jsp中的操作调用：

Struts配置：

<action name="search" class="com.view.SearchAction"method="search">
            <result name="input" type="tiles">search</result>
            <result name="success" type="tiles">search</result>
            <result name="error" type="tiles">search</result>                               
</action>

---

我已经知道你的错误了。如果我很好地提醒解决方案，则对象formatList为null或空。

重定向页面的代码在哪里？

formatList

不是集合/数组/映射/枚举/迭代器类型。私有列表formatList；public List getFormatList（）{return formatList；}public void setFormatList（List formatList）{this.formatList=formatList；}@user3189778不要在注释中发布代码，编辑您的问题并更新内容。也发布JSP代码。发布您的JSP。您可能会使用不同的。。您没有在操作类中设置

formateList

的值。空集合不会生成异常。

<action name="search" class="com.view.SearchAction"method="search">
            <result name="input" type="tiles">search</result>
            <result name="success" type="tiles">search</result>
            <result name="error" type="tiles">search</result>                               
</action>

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

More on this error:

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    org.apache.jsp.views.search_jsp._jspx_meth_s_005fselect_005f0(search_jsp.java:1222)
    org.apache.jsp.views.search_jsp._jspx_meth_s_005fform_005f0(search_jsp.java:765)
    org.apache.jsp.views.search_jsp._jspService(search_jsp.java:181)
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