最近工作中需要在项目中集成webflow，由于原来的项目本身就使用的springmvc，集成起来的配置也就比较简单。有关webflow的介绍请参考 

http://www.ibm.com/developerworks/cn/education/java/j-spring-webflow/

http://projects.spring.io/spring-webflow/

下面奉上一个简单的购物车的demo。（下载地址 https://git.oschina.net/lastLin/webflow-demo.git）

首先，引入 spring-binding-2.4.0.RELEASE.jar，spring-js-2.4.0.RELEASE.jar，spring-webflow-2.4.0.RELEASE.jar3个jar包。

接下来创建 webflow-config.xml 文件，webflow的一些基础配置都放在这个文件中，其中引入了两个webflow的配置文件paying.xml和addToCart.xml 。  内容如下

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:webflow="http://www.springframework.org/schema/webflow-config"
    xsi:schemaLocation=" http://www.springframework.org/schema/beans 
    http://www.springframework.org/schema/beans/spring-beans-2.5.xsd 
    http://www.springframework.org/schema/webflow-config 
    http://www.springframework.org/schema/webflow-config/spring-webflow-config-2.0.xsd">
    
    <bean id="flowController" class="org.springframework.webflow.mvc.servlet.FlowController">
        <property name="flowExecutor" ref="flowExecutor" />
    </bean>

    <webflow:flow-executor id="flowExecutor" />
    
    <bean id="viewMappings"
        class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">
        <!-- /paying 请求由 flowController 来处理 -->
        <property name="mappings">
            <value> /paying=flowController </value>
        </property>
        <property name="defaultHandler">
            <!-- UrlFilenameViewController 会将 "/index" 这样的请求映射成名为 "index" 的视图 -->
            <bean class="org.springframework.web.servlet.mvc.UrlFilenameViewController" />
        </property>
    </bean>
    <!-- 所有 flow的定义文件它的位置在这里进行配置， flow-builder-services 用于配置 flow 的特性 -->
    <webflow:flow-registry id="flowRegistry"
        flow-builder-services="flowBuilderServices">
        <webflow:flow-location path="/WEB-INF/flows/paying.xml"
            id="paying" />
        <webflow:flow-location path="/WEB-INF/flows/addToCart.xml"
            id="addToCart" />
        <!-- <webflow:flow-location path="/WEB-INF/flow/*.xml" /> -->
    </webflow:flow-registry>



    <!--Web Flow 中的视图通过 MVC 框架的视图技术来呈现 -->
    <webflow:flow-builder-services id="flowBuilderServices"
        view-factory-creator="mvcViewFactoryCreator" />

    <!-- freemarker视图 -->
    <bean id="mvcViewFactoryCreator"
        class="org.springframework.webflow.mvc.builder.MvcViewFactoryCreator">
        <property name="viewResolvers" ref="freemarkerViewResolver" />
    </bean>
</beans>

在springmvc的配置文件中引入 webflow-config.xml 文件

<!-- 加载web-flow -->
    <import resource="webflow-config.xml" />

addToCart.xml文件中描述了将商品添加到购物车中的动作

<?xml version="1.0" encoding="UTF-8"?>
<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-2.0.xsd">
    <on-start>
        <set name="requestScope.productId" value="requestParameters.productId" />
    </on-start>
    <action-state id="addToCart">
        <evaluate expression="cart.addItem(productService.getProduct(productId))" />
        <transition to="productAdded" />
    </action-state>
    <end-state id="productAdded" />
</flow>

paying.xml则描述了付款的动作

<?xml version="1.0" encoding="UTF-8"?>
<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-2.0.xsd">

    <var name="mycart" class="org.webflow.demo.Cart" />
    <on-start>
        <set name="conversationScope.cart" value="mycart"></set>
    </on-start>
    <!-- view-state中的view对应jsp文件夹中的jsp页面，on是触发事件，to对应state id -->
    <view-state id="viewCart" view="/webflow/viewCart">
        <on-render>
            <!-- 要在 viewCart 页面中显示商品，只需在 view-state 元素的 on-render 切入点调用 productService 
                的 getProducts 方法，并将所得结果保存到 viewScope 中即可 -->
            <evaluate expression="productService.getProducts()" result="viewScope.products" />
        </on-render>
        <transition on="submit" to="viewOrder" />
        <transition on="addToCart" to="addProductToCart" />
    </view-state>
    
    <subflow-state id="addProductToCart" subflow="addToCart">
        <transition on="productAdded" to="viewCart" />
    </subflow-state>
    
    <view-state id="viewOrder" view="webflow/viewOrder">
        <transition on="confirm" to="orderConfirmed">
        </transition>
    </view-state>
    <view-state id="orderConfirmed" view="webflow/orderConfirmed">
        <transition on="returnToIndex" to="returnToIndex">
        </transition>
    </view-state>
    <end-state id="returnToIndex" view="webflow/index">
    </end-state>
</flow>

整个webflow的配置到这里基本就完成了。