大家好！
我正在尝试使用 Spring roo 实现文件上传。文件路径将持久化在数据库中，文件将保存在文件系统中。根据spring dveloper board上的信息，我修改了input.tagx和create.tagx文件。（信息：https ://jira.springsource.org/browse/ROO-442）input.tagx：
<jsp:root xmlns:c="http://java.sun.com/jsp/jstl/core" xmlns:fn="http://java.sun.com/jsp/jstl/functions" xmlns:spring="http://www.springframework.org/tags" xmlns:form="http://www.springframework.org/tags/form" xmlns:jsp="http://java.sun.com/JSP/Page" version="2.0">
<jsp:output omit-xml-declaration="yes" />
<jsp:directive.attribute name="id" type="java.lang.String" required="true" rtexprvalue="true" description="The identifier for this tag (do not change!)" />
<jsp:directive.attribute name="field" type="java.lang.String" required="true" rtexprvalue="true" description="The field exposed from the form backing object" />
<jsp:directive.attribute name="label" type="java.lang.String" required="false" rtexprvalue="true" description="The label used for this field, will default to a message bundle if not supplied" />
<jsp:directive.attribute name="labelCode" type="java.lang.String" required="false" rtexprvalue="true" description="Key for label message bundle if label is not supplied" />
<jsp:directive.attribute name="required" type="java.lang.Boolean" required="false" rtexprvalue="true" description="Indicates if this field is required (default false)" />
<jsp:directive.attribute name="disabled" type="java.lang.Boolean" required="false" rtexprvalue="true" description="Specify if this field should be enabled" />
<jsp:directive.attribute name="validationRegex" type="java.lang.String" required="false" rtexprvalue="true" description="Specify regular expression to be used for the validation of the input contents" />
<jsp:directive.attribute name="validationMessageCode" type="java.lang.String" required="false" rtexprvalue="true" description="Specify the message (message property code) to be displayed if the regular expression validation fails" />
<jsp:directive.attribute name="validationMessage" type="java.lang.String" required="false" rtexprvalue="true" description="Specify the message to be displayed if the regular expression validation fails" />
<c:if test="${empty render or render}"
<c:when test="${disableFormBinding}">
<input id="_${field}_id" name="${field}" type="${type}"/>
</c:when>
<c:otherwise>
<!-- currently (spring 3.0.3), form:input doesn't support type attribute -->
<!-- <form:input id="_${field}_id" path="${field}" disabled="${disabled}"/> -->
<input id="_${field}_id" name="${field}" type="${type}"/>
<br/>
<form:errors cssClass="errors" id="_${field}_error_id" path="${field}"/>
</c:otherwise>
<c:if test="${empty disabled}">
<c:set value="false" var="disabled" />
</c:if>
<c:if test="${empty label}">
<c:if test="${empty labelCode}">
<c:set var="labelCode" value="${fn:substringAfter(id,'_')}" />
</c:if>
<spring:message code="label_${fn:toLowerCase(labelCode)}" var="label" htmlEscape="false" />
</c:if>
<c:if test="${empty validationMessage}">
<c:choose>
<c:when test="${empty validationMessageCode}">
<spring:message arguments="${fn:escapeXml(label)}" code="field_invalid" var="field_invalid" htmlEscape="false" />
</c:when>
<c:otherwise>
<spring:message arguments="${fn:escapeXml(label)}" code="${validationMessageCode}" var="field_invalid" htmlEscape="false" />
</c:otherwise>
</c:choose>
</c:if>
<c:if test="${empty required}">
<c:set value="false" var="required" />
</c:if>
<c:set var="sec_field">
<spring:escapeBody javaScriptEscape="true" >${field}</spring:escapeBody>
</c:set>
<div id="_${fn:escapeXml(id)}_id">
<label for="_${sec_field}_id">
<c:out value="${fn:escapeXml(label)}" />
:
</label>
<c:choose>
<c:when test="${disableFormBinding}">
<input id="_${sec_field}_id" name="${sec_field}" type="${fn:escapeXml(type)}" />
</c:when>
<c:otherwise>
<c:choose>
<c:when test="${type eq 'password'}">
<form:password id="_${sec_field}_id" path="${sec_field}" disabled="${disabled}" />
</c:when>
<c:otherwise>
<form:input id="_${sec_field}_id" path="${sec_field}" disabled="${disabled}" />
</c:otherwise>
</c:choose>
<br />
<form:errors cssClass="errors" id="_${sec_field}_error_id" path="${sec_field}" />
</c:otherwise>
</c:choose>
<c:choose>
<c:when test="${required}">
<spring:message code="field_required" var="field_required" htmlEscape="false" />
<spring:message argumentSeparator="," arguments="${label},(${field_required})" code="field_simple_validation" var="field_validation" htmlEscape="false" />
</c:when>
<c:otherwise>
<spring:message argumentSeparator="," arguments="${label}, " code="field_simple_validation" var="field_validation" htmlEscape="false" />
</c:otherwise>
</c:choose>
<c:set var="sec_field_validation">
<spring:escapeBody javaScriptEscape="true">${field_validation}</spring:escapeBody>
</c:set>
<c:set var="sec_field_invalid">
<spring:escapeBody javaScriptEscape="true" htmlEscape="true">${field_invalid}</spring:escapeBody>
</c:set>
<c:set var="sec_field_required">
<spring:escapeBody javaScriptEscape="true">${field_required}</spring:escapeBody>
</c:set>
<c:set var="sec_validation_regex" value="" />
<c:if test="${!empty validationRegex}">
<c:set var="sec_validation_regex" value="regExp : '${validationRegex}', " />
</c:if>
<script type="text/javascript">
Spring.addDecoration(new Spring.ElementDecoration({elementId : '_${sec_field}_id', widgetType : 'dijit.form.ValidationTextBox', widgetAttrs : {promptMessage: '${sec_field_validation}', invalidMessage: '${sec_field_invalid}', required : ${required}, ${sec_validation_regex} missingMessage : '${sec_field_required}' }}));
</script>
</div>
<br />
</c:if>
</jsp:root>
创建.tagx：
<jsp:root xmlns:c="http://java.sun.com/jsp/jstl/core" xmlns:fn="http://java.sun.com/jsp/jstl/functions" xmlns:util="urn:jsptagdir:/WEB-INF/tags/util" xmlns:form="http://www.springframework.org/tags/form" xmlns:jsp="http://java.sun.com/JSP/Page" xmlns:spring="http://www.springframework.org/tags" version="2.0">
<jsp:output omit-xml-declaration="yes"/>
<jsp:directive.attribute name="id" type="java.lang.String" required="true" rtexprvalue="true" description="The identifier for this tag (do not change!)"/>
<jsp:directive.attribute name="modelAttribute" type="java.lang.String" required="true" rtexprvalue="true" description="The name of the model attribute for form binding"/>
<jsp:directive.attribute name="path" type="java.lang.String" required="true" rtexprvalue="true" description="Specify the relative URL path (wit leading /)" />
<jsp:directive.attribute name="compositePkField" type="java.lang.String" required="false" rtexprvalue="true" description="The field name of the composite primary key (only used if a composite PK is present in the form backing object)" />
<jsp:directive.attribute name="multipart" type="java.lang.Boolean" required="false" rtexprvalue="true" description="Indicate if this is a multipart form (default: false)" />
<jsp:directive.attribute name="label" type="java.lang.String" required="false" rtexprvalue="true" description="The label used for this object, will default to a message bundle if not supplied"/>
<jsp:directive.attribute name="render" type="java.lang.Boolean" required="false" rtexprvalue="true" description="Indicate if the contents of this tag and all enclosed tags should be rendered (default 'true')" />
<jsp:directive.attribute name="openPane" type="java.lang.Boolean" required="false" rtexprvalue="true" description="Control if the title pane is opened or closed by default (default: true)"/>
<jsp:directive.attribute name="z" type="java.lang.String" required="false" description="Used for checking if element has been modified (to recalculate simply provide empty string value)"/>
<jsp:directive.attribute name="enctype" type="java.lang.String" required="false" description="Used to set the enctype, e.g. multipart/form-data for file upload support. "/>
<c:if test="${empty render or render}">
<c:if test="${empty label}">
<spring:message code="label_${fn:toLowerCase(fn:substringAfter(id,'_'))}" var="label" htmlEscape="false" />
</c:if>
<!--<c:set var="enctype" value="application/x-www-form-urlencoded"/> -->
<form:form action="${form_url}" method="POST" modelAttribute="${modelAttribute}" enctype="${enctype}">
</form:form>
<c:if test="${multipart}">
<c:set var="enctype" value="multipart/form-data"/>
</c:if>
<spring:message arguments="${label}" code="entity_create" var="title_msg" htmlEscape="false" />
<util:panel id="${id}" title="${title_msg}" openPane="${openPane}">
<spring:url value="${path}" var="form_url"/>
<c:set var="jsCall" value=""/>
<c:if test="${not empty compositePkField}">
<c:set var="jsCall" value="encodePk()" />
</c:if>
<form:form action="${form_url}" method="POST" modelAttribute="${modelAttribute}" enctype="${enctype}" onsubmit="${jsCall}">
<form:errors cssClass="errors" delimiter="<p/>"/>
<c:if test="${not empty compositePkField}">
<form:hidden id="_${fn:escapeXml(compositePkField)}_id" path="${fn:escapeXml(compositePkField)}" />
<script type="text/javascript">
<![CDATA[
dojo.require("dojox.encoding.base64");
function encodePk() {
var obj = new Object();
dojo.query("input[name^=\"${compositePkField}.\"]").forEach(function(node, index, nodelist){
obj[node.name.substring('${compositePkField}'.length + 1)] = node.value;
});
var json = dojo.toJson(obj);
var tokArr = [];
for (var i = 0; i < json.length; i++) {
tokArr.push(json.charCodeAt(i));
}
var encoded = dojox.encoding.base64.encode(tokArr);
dojo.byId('_${fn:escapeXml(compositePkField)}_id').value = encoded;
}
]]>
</script>
</c:if>
<jsp:doBody />
<div class="submit" id="${fn:escapeXml(id)}_submit">
<spring:message code="button_save" var="save_button" htmlEscape="false" />
<script type="text/javascript">Spring.addDecoration(new Spring.ValidateAllDecoration({elementId:'proceed', event:'onclick'}));</script>
<input id="proceed" type="submit" value="${fn:escapeXml(save_button)}"/>
</div>
</form:form>
</util:panel>
</c:if>
</jsp:root>
我的问题是我得到了休闲错误：
javax.servlet.jsp.JspTagException: Illegal use of <when>-style tag without <choose> as its direct parent
at org.apache.taglibs.standard.tag.common.core.WhenTagSupport.doStartTag(WhenTagSupport.java:95)
at org.apache.jsp.tag.web.form.fields.input_tagx._jspx_meth_c_005fwhen_005f0(input_tagx.java:519)
at org.apache.jsp.tag.web.form.fields.input_tagx.doTag(input_tagx.java:325)
at org.apache.jsp.WEB_002dINF.views.pphotoes.create_jspx._jspx_meth_field_005finput_005f0(create_jspx.java:172)
at org.apache.jsp.WEB_002dINF.views.pphotoes.create_jspx.access$2(create_jspx.java:157)
我究竟做错了什么？（我认为我的控制器和实体文件很好，如果需要我可以发布它们）
感谢您的帮助。干杯。