Java 单击另一个链接时，是否希望在同一jsp页面中再添加一个选项

我有一个jsp页面（假设为asdf），其中有两个链接（假设为link.ab、link.cd）。两者都指向同一个jsp（假设是qwerty），并且有3列可用..但是如果我单击link.ab，则将显示3列，如果我单击link.cd，则应显示4列--我不知道如何显示。。 我正在尝试此代码，但请求处理失败时出现错误；嵌套异常

<tbody>
<tr>
 <c:choose>
    <c:when test="${addQuestionLink}"></c:when>
<td class="label">
    <form:label path="ins_org">
        <span class="requiredFieldMarker"><fmt:message key="label.requiredMarker"/></span>
        <fmt:message key="label.institute"/><fmt:message key="label.postfix"/>
    </form:label>
</td>
<td class="data">
    <form:select path="ins_org" >
    <form:option value=""><fmt:message key="label.general.select"/></form:option>
    <form:options items="${agecy}" itemLabel="agecyName" itemValue="agecyCode"/>
        </form:select>
</td>
<td class="label">
    <form:label path="cate">
            <span class="requiredFieldMarker"><fmt:message key="label.requiredMarker"/></span><fmt:message key="label.cate"/><fmt:message key="label.postfix"/>
    </form:label>
</td>
<td class="data" >
    <form:select path="cate">
        <form:option value=""><fmt:message key="label.select"/></form:option>
        <form:options items="${refcate}" itemValue="refCode" itemLabel="refDesc"/>
    </form:select>
</td>
<td class="label">
    <form:label path="level">
            <span class="requiredFieldMarker"><fmt:message key="label.requiredMarker"/></span><fmt:message key="label.level"/><fmt:message key="label.postfix"/>
    </form:label>
</td>
<td class="data" >
    <form:select path="level">
        <form:option value=""><fmt:message key="label.select"/></form:option>
        <form:options items="${refLevel}" itemValue="refCode" itemLabel="refDesc"/>
    </form:select>
</td>
<td class="label">
    <form:label path="noOfQuestions">
            <span class="requiredFieldMarker"><fmt:message key="label.requiredMarker"/></span><fmt:message key="label.noofQuestions"/><fmt:message key="label.postfix"/>
    </form:label>
</td>
<td class="data" >
    <form:input path="noOfQuestions" maxlength="3" size="5"/>
</td>
</c:choose>
<c:otherwise>
<td class="label">
    <form:label path="cate">
            <span class="requiredFieldMarker"><fmt:message key="label.requiredMarker"/></span><fmt:message key="label.cate"/><fmt:message key="label.postfix"/>
    </form:label>
</td>
<td class="data" >
    <form:select path="cate">
        <form:option value=""><fmt:message key="label.select"/></form:option>
        <form:options items="${refcate}" itemValue="refCode" itemLabel="refDesc"/>
    </form:select>
</td>
<td class="label">
    <form:label path="level">
            <span class="requiredFieldMarker"><fmt:message key="label.requiredMarker"/></span><fmt:message key="label.level"/><fmt:message key="label.postfix"/>
    </form:label>
</td>
<td class="data" >
    <form:select path="level">
        <form:option value=""><fmt:message key="label.select"/></form:option>
        <form:options items="${refLevel}" itemValue="refCode" itemLabel="refDesc"/>
        </form:select>
</td>
<td class="label">
    <form:label path="noOfQuestions">
            <span class="requiredFieldMarker"><fmt:message key="label.requiredMarker"/></span><fmt:message key="label.noofQuestions"/><fmt:message key="label.postfix"/>
    </form:label>
</td>
<td class="data" >
    <form:input path="noOfQuestions" maxlength="3" size="5"/>
</td>
</c:otherwise>
</tr>       
</tbody>                

嵌套的异常是。。。？为什么不简单地粘贴整个stacktrace？因为两个链接都有不同的业务-Antoniossssorg.apache.tiles.impl.CannotRenderException:ServletException这是个例外-Antoniossss