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.