不能在 Spring Web Flow 定义中使用 var 元素吗？

Question

我正试图根据文档在流中声明一个变量，使用

<var name="myVar" class="int" />

然而，Eclipse将var突出显示为一个错误，并且在运行流时（无论是从Eclipse内部还是从独立的jar），我都会得到一个解析器异常：

org.xml.sax.SAXParseException: cvc-complex-type.2.4.a: Invalid content was found starting with element 'var'. One of '{"http://www.springframework.org/schema/webflow":input, "http://www.springframework.org/schema/webflow":on-start, "http://www.springframework.org/schema/webflow":action-state, "http://www.springframework.org/schema/webflow":view-state, "http://www.springframework.org/schema/webflow":decision-state, "http://www.springframework.org/schema/webflow":subflow-state, "http://www.springframework.org/schema/webflow":end-state, "http://www.springframework.org/schema/webflow":global-transitions, "http://www.springframework.org/schema/webflow":on-end, "http://www.springframework.org/schema/webflow":output, "http://www.springframework.org/schema/webflow":exception-handler, "http://www.springframework.org/schema/webflow":bean-import}' is expected.
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:203)
    at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.error(ErrorHandlerWrapper.java:134)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:437)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:368)
    at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:325)
    at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator$XSIErrorReporter.reportError(XMLSchemaValidator.java:458)
    at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.reportSchemaError(XMLSchemaValidator.java:3237)
    at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.handleStartElement(XMLSchemaValidator.java:1796)
    at com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaValidator.emptyElement(XMLSchemaValidator.java:766)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.scanStartElement(XMLNSDocumentScannerImpl.java:356)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:2786)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:606)
    at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:117)
    at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:510)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:848)
    at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:777)
    at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:141)
    at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:243)
    at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:348)
    at javax.xml.parsers.DocumentBuilder.parse(DocumentBuilder.java:121)
    at org.springframework.webflow.engine.model.builder.xml.DefaultDocumentLoader.loadDocument(DefaultDocumentLoader.java:113)
    at org.springframework.webflow.engine.model.builder.xml.XmlFlowModelBuilder.init(XmlFlowModelBuilder.java:112)

我使用的是最新的XSD:

<flow xmlns="http://www.springframework.org/schema/webflow"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/webflow
        http://www.springframework.org/schema/webflow/spring-webflow.xsd">

我已经验证了Spring服务器和jar中的2.4 XSD实际上包含了var元素的定义，以及input、on-start和其他工作元素。

你知道问题出在哪里吗？

Answer 1

我认为您正在某个操作状态或其他状态中使用var元素var元素用于在流启动时设置值。如果您想在一个状态中设置一些值，请使用set元素。有时，我们使用input元素从当前流中访问的调用方流中获取值。

var元素可以在流的开头使用，如下所示：

    <flow xmlns="http://www.springframework.org/schema/webflow"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/webflow
    http://www.springframework.org/schema/webflow/spring-webflow.xsd">
    <var name="someVarName" class="someClassName"/>
    <action-state id="myActionState">
        <set name="someName" value="123"/>
        <evaluate expression="myAction.methodInMyAction()"/>
        <transition on="..." to="..." />
    </action-state>
    ...
    </flow>

Answer 2

我认为var声明只支持类而不支持本机类型。所以变量应该声明为

<var name="myVar" class="java.lang.Integer"/>