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

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <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
 3 http://www.springframework.org/schema/webflow/spring-webflow-2.3.xsd">
 4     <input name="order" required="true" />
 5     <view-state id="showOrder">
 6         <transition on="createPizza" to="createPizza" />
 7         <transition on="checkout" to="orderCreated" />
 8         <transition on="cancel" to="cancel" />
 9     </view-state>
10     <view- state id="createPizza" model="flowScope.pizza">
11         <on-entry>
12             <set name="flowScope.pizza" value="new com.springinaction.pizza.domain.Pizza()" />
13             <evaluate result="viewScope.toppingsList" expression="T(com.springinaction.pizza.domain.Topping).asList()" />
14         </on-entry>
15         <transition on="addPizza" to="showOrder">
16             <evaluate expression="order.addPizza(flowScope.pizza)" />
17         </transition>
18         <transition on="cancel" to="showOrder" />
19         </view-state>
20         <end-state id="cancel" / <end-state id="orderCreated" />
21 </flow>

或者

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <flow xmlns="http://www.springframework.org/schema/webflow"
 3   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4   xsi:schemaLocation="http://www.springframework.org/schema/webflow 
 5   http://www.springframework.org/schema/webflow/spring-webflow-2.0.xsd">
 6 
 7     <input name="order" required="true" />
 8     
 9     <!-- Order -->
10     <view-state id="showOrder">
11         <transition on="createPizza" to="createPizza" />
12         <transition on="checkout" to="orderCreated" />
13         <transition on="cancel" to="cancel" />
14     </view-state>
15 
16     <view-state id="createPizza" model="flowScope.pizza">
17         <on-entry>
18           <set name="flowScope.pizza" 
19               value="new com.springinaction.pizza.domain.Pizza()" />
20               
21           <evaluate result="viewScope.toppingsList" 
22               expression="T(com.springinaction.pizza.domain.Topping).asList()" />
23         </on-entry>
24         <transition on="addPizza" to="showOrder">
25           <evaluate expression="order.addPizza(flowScope.pizza)" />
26         </transition>
27         <transition on="cancel" to="showOrder" />
28     </view-state>
29 
30         
31     <!-- End state -->
32     <end-state id="cancel" />
33     <end-state id="orderCreated" />
34 </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

 1 <%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
 2 <div>
 3 
 4     <h2>Create Pizza</h2>
 5     <form:form commandName="pizza">
 6       <input type="hidden" name="_flowExecutionKey" 
 7           value="${flowExecutionKey}"/>
 8     
 9       <b>Size: </b><br/>
10       <form:radiobutton path="size" label="Small (12-inch)" value="SMALL"/><br/>
11     <form:radiobutton path="size" label="Medium (14-inch)" value="MEDIUM"/><br/>
12     <form:radiobutton path="size" label="Large (16-inch)" value="LARGE"/><br/>
13     <form:radiobutton path="size" label="Ginormous (20-inch)" value="GINORMOUS"/><br/>
14       <br/>
15       
16       <b>Toppings: </b><br/>
17       <form:checkboxes path="toppings" items="${toppingsList}" 
18                        delimiter="<br/>"/><br/><br/>
19 
20           
21       <input type="submit" class="button" 
22           name="_eventId_addPizza" value="Continue"/>
23       <input type="submit" class="button" 
24           name="_eventId_cancel" value="Cancel"/>          
25     </form:form>
26 </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.