使用<@ s.generator和迭代器標籤時獲取「Freemarker模板錯誤」

我正在學習Struts 2.在使用FreeMarker模板創建視圖時，出現錯誤。我使用的Eclipse IDE，並在Tomcat中運行的應用程序8.使用<@ s.generator和迭代器標籤時獲取「Freemarker模板錯誤」

的Freemarker代碼：

<!DOCTYPE html> 
    <html> 
    <head> 
     <meta charset="UTF-8"> 
    <title>Insert title here</title> 
    </head> 
    <body> 
     <h1>Sample...(FreeMarker)</h1><br><br>  
     <div> 
      <@s.generator separator="," val="%{'15,20,30,40,50'}"> 
       Last entered protein Values -:<br> 
       <@s.iterator> 
        <@s.property /><br> 
       </@s.iterator> 
      </@s.generator> 
     </div>  
    </body> 
    </html>

Eclipse控制檯跟蹤日誌：

> Jul 14, 2016 8:19:02 PM 
    > com.opensymphony.xwork2.util.logging.jdk.JdkLogger error SEVERE: 
    > Exception occurred during processing request: The following has 
    > evaluated to null or missing: 
    > ==> s.generator [in template "WEB-INF/content/enter-protein.ftl" at line 10, column 11] 
    > 
    > ---- Tip: It's the step after the last dot that caused this error, not those before it. 
    > ---- Tip: If the failing expression is known to be legally refer to something that's null or missing, either specify a default value like 
    > myOptionalVar!myDefault, or use <#if 
    > myOptionalVar??>when-present<#else>when-missing</#if>. (These only 
    > cover the last step of the expression; to cover the whole expression, 
    > use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)?? 
    > ---- 
    > 
    > ---- FTL stack trace ("~" means nesting-related): 
    > - Failed at: @s.generator separator="," val="%{'15... [in template "WEB-INF/content/enter-protein.ftl" at line 16, column 9] 
    > ---- FreeMarker template error: The following has evaluated to null or missing: 
    > ==> s.generator [in template "WEB-INF/content/enter-protein.ftl" at line 16, column 11] 
    > 
    > ---- Tip: It's the step after the last dot that caused this error, not those before it. 
    > ---- Tip: If the failing expression is known to be legally refer to something that's null or missing, either specify a default value like 
    > myOptionalVar!myDefault, or use <#if 
    > myOptionalVar??>when-present<#else>when-missing</#if>. (These only 
    > cover the last step of the expression; to cover the whole expression, 
    > use parenthesis: (myOptionalVar.foo)!myDefault, (myOptionalVar.foo)?? 
    > ---- 
    > 
    > ---- FTL stack trace ("~" means nesting-related): 
    > - Failed at: @s.generator separator="," val="%{'15... [in template "WEB-INF/content/enter-protein.ftl" at line 16, column 9] 
    > ---- 
    > 
    > Java stack trace (for programmers): 
    > ---- freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...]  at 
    > freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:116) 
    > at freemarker.core.UnifiedCall.accept(UnifiedCall.java:112)  at 
    > freemarker.core.Environment.visit(Environment.java:312) at 
    > freemarker.core.MixedContent.accept(MixedContent.java:62)  at 
    > freemarker.core.Environment.visit(Environment.java:312) at 
    > freemarker.core.Environment.process(Environment.java:290)  at 
    > freemarker.template.Template.process(Template.java:312) at 
    > org.apache.struts2.views.freemarker.FreemarkerResult.doExecute(FreemarkerResult.java:223) 
    > at 
    > org.apache.struts2.dispatcher.StrutsResultSupport.execute(StrutsResultSupport.java:191) at 
. 
. 
. 
. 
    ........................ So on...........

奇怪的是，當我嘗試在JSP相同，它完美無瑕！（在JSP中，我們使用的<s:something>代替<@s.something>）

來源

2016-07-14 hvsharma

的<s:generator>標籤很簡單不是那種可以在Freemarker模板中使用的標記*的。

好的部分是：它根本不需要。您可以使用<s:iterator>標籤，不帶<s:generator>。

使用迭代器標籤的value屬性來設置迭代源和OGNL表達式{e1,e2,e3}來創建列表。

<@s.iterator value="{15,20,30,40,50}"> 
    <@s.property /><br> 
</@s.iterator>

*想知道哪些Struts2標籤可以在FreeMarker模板中使用？見 DefaultTagLibrary#getDirectiveClasses方法。

來源

2016-07-14 16:48:14

這是我在stackoverflow上的第一篇文章。我想知道我什麼時候能解決這個問題。它很早就解決了。謝謝。我喜歡你也爲我提供了這個參考。 :) – hvsharma

@hvsharma歡迎來到SO。很棒的第一篇文章 –

FreeMarker有自己的迭代器指令（'＃list'及其朋友）......我不知道Struts的最佳實踐是什麼，但這對我來說看起來很奇怪。 – ddekany

使用<@ s.generator和迭代器標籤時獲取「Freemarker模板錯誤」

回答

相關問題