SpringMVC中集成web flow

最近工做中须要在项目中集成webflow，因为原来的项目自己就使用的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。

接下来建立 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 。  内容以下

<?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>
	<!-- 全部 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 中的视图经过 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做

<?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则描述了付款的动做

<?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 中便可 -->
			<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。