SPRING IN ACTION 第4版笔记-第八章Advanced Spring MVC-005-Pizza例子的订单流程()

一、

1.订单流程定义文件order-flow.xml

 <?xml version="1.0" encoding="UTF-8"?>
 <flow xmlns="http://www.springframework.org/schema/webflow" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" Listing 8.8 Order subflow view shows states to display the order and create a pizza create Pizza S Start cancel order Created createPizza cancel/addPizza checkout cancel showOrder Figure 8.4 Pizzas are added via the order subflow. www.it-ebooks.info 239 Putting it all together: the pizza flow xsi:schemaLocation="http://www.springframework.org/schema/webflow
 http://www.springframework.org/schema/webflow/spring-webflow-2.3.xsd">
     <input name="order" required="true" />
     <view-state id="showOrder">
         <transition on="createPizza" to="createPizza" />
         <transition on="checkout" to="orderCreated" />
         <transition on="cancel" to="cancel" />
     </view-state>
     <view- state id="createPizza" model="flowScope.pizza">
         <on-entry>
             <set name="flowScope.pizza" value="new com.springinaction.pizza.domain.Pizza()" />
             <evaluate result="viewScope.toppingsList" expression="T(com.springinaction.pizza.domain.Topping).asList()" />
         </on-entry>
         <transition on="addPizza" to="showOrder">
             <evaluate expression="order.addPizza(flowScope.pizza)" />
         </transition>
         <transition on="cancel" to="showOrder" />
         </view-state>
         <end-state id="cancel" / <end-state id="orderCreated" />
 </flow>

或者

 <?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">

     <input name="order" required="true" />

     <!-- Order -->
     <view-state id="showOrder">
         <transition on="createPizza" to="createPizza" />
         <transition on="checkout" to="orderCreated" />
         <transition on="cancel" to="cancel" />
     </view-state>

     <view-state id="createPizza" model="flowScope.pizza">
         <on-entry>
           <set name="flowScope.pizza"
               value="new com.springinaction.pizza.domain.Pizza()" />

           <evaluate result="viewScope.toppingsList"
               expression="T(com.springinaction.pizza.domain.Topping).asList()" />
         </on-entry>
         <transition on="addPizza" to="showOrder">
           <evaluate expression="order.addPizza(flowScope.pizza)" />
         </transition>
         <transition on="cancel" to="showOrder" />
     </view-state>

     <!-- End state -->
     <end-state id="cancel" />
     <end-state id="orderCreated" />
 </flow>

The <on-entry> element adds a new Pizza object to flow scope to be populated when the form is submitted. Note that the model of this view state references the same flow-scoped Pizza object. That Pizza object is bound to the Create Pizza form, shown next.

2.createPizza.jsp

 <%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
 <div>

     <h2>Create Pizza</h2>
     <form:form commandName="pizza">
       <input type="hidden" name="_flowExecutionKey"
           value="${flowExecutionKey}"/>

       <b>Size: </b><br/>
       <form:radiobutton path="size" label="Small (12-inch)" value="SMALL"/><br/>
     <form:radiobutton path="size" label="Medium (14-inch)" value="MEDIUM"/><br/>
     <form:radiobutton path="size" label="Large (16-inch)" value="LARGE"/><br/>
     <form:radiobutton path="size" label="Ginormous (20-inch)" value="GINORMOUS"/><br/>
       <br/>

       <b>Toppings: </b><br/>
       <form:checkboxes path="toppings" items="${toppingsList}"
                        delimiter="<br/>"/><br/><br/>

       <input type="submit" class="button"
           name="_eventId_addPizza" value="Continue"/>
       <input type="submit" class="button"
           name="_eventId_cancel" value="Cancel"/>
     </form:form>
 </div>

When the form is submitted via the Continue button, the size and topping selections are bound to the Pizza object, and the addPizza transition is taken. The <evaluate> element associated with that transition indicates that the flow-scoped Pizza object should be passed in a call to the order’s addPizza() method before transitioning to the showOrder state.