第8章 使用Spring Web Flow--学习一个简单例子

概述：

Spring 的工作流就是类似网上购物，注册用户-》选择商品-》添加到购物车-》付款-》收货-》售后，一套已经固化的流程。

学习博文地址：

http://blog.csdn.net/hejingyuan6/article/details/46723021 写到非常好，大家可以跟着学习一下

看一下工程结构：

操作步骤：

step1、引入spring web flow jar 当前还要普通Spring相关jar包

<dependency>
<groupId>org.springframework.webflow</groupId>
<artifactId>spring-webflow</artifactId>
<version>2.4.5.RELEASE</version>
</dependency>

step2、配置运行环境

配置web.xml

<?xml version="1.0" encoding="UTF-8"?><web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" version="3.0">  <display-name>webflow</display-name>  <servlet>  <servlet-name>webServlet</servlet-name>  <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>  <init-param>  <param-name>contextConfigLocation</param-name>  <param-value>classpath:spring-mvc.xml</param-value>  </init-param>  <load-on-startup>1</load-on-startup>  </servlet>  <servlet-mapping>  <servlet-name>webServlet</servlet-name>  <url-pattern>/spring/*</url-pattern>  </servlet-mapping>  <welcome-file-list>    <welcome-file>index.html</welcome-file>    <welcome-file>index.htm</welcome-file>    <welcome-file>index.jsp</welcome-file>    <welcome-file>default.html</welcome-file>    <welcome-file>default.htm</welcome-file>    <welcome-file>default.jsp</welcome-file>  </welcome-file-list></web-app>

配置集合Springmvc+flow配置文件

<?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:context="http://www.springframework.org/schema/context"      xsi:schemaLocation="http://www.springframework.org/schema/beans       http://www.springframework.org/schema/beans/spring-beans-2.5.xsd       http://www.springframework.org/schema/context       http://www.springframework.org/schema/context/spring-context-2.5.xsd">   <context:component-scan base-package="com.jack"/> <!-- 启动配置注解 --> <context:annotation-config/> <import resource="webmvc.xml"/> <import resource="webflow.xml"/> </beans>

配置Springmvc

<?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:context="http://www.springframework.org/schema/context"      xsi:schemaLocation="http://www.springframework.org/schema/beans       http://www.springframework.org/schema/beans/spring-beans-2.5.xsd       http://www.springframework.org/schema/context       http://www.springframework.org/schema/context/spring-context-2.5.xsd">    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/> <property name="prefix" value="/WEB-INF/jsp/"></property> <property name="suffix" value=".jsp"/> </bean>  <!-- SimpleUrlHandlerMapping 通过配置文件，把一个URL映射到Controller --> <bean id="viewMappings"  class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping"> <property name="mappings"> <value>/shopping.do=flowController</value> </property> <property name="defaultHandler"> <bean class="org.springframework.web.servlet.mvc.UrlFilenameViewController"/> </property> </bean> <bean id="flowController" class="org.springframework.webflow.mvc.servlet.FlowController"> <property name="flowExecutor" ref="flowExecutor"/> </bean> </beans>

总结：

1、首先配置jsp通用的视图解析器viewResolver

2、SimpleUrlHandlerMapping 可以将map与控制器类关联，格式类似： path = 控制器。例如上 /shopping.do = flowController（flowController 也就是工作流的入口）

3、UrlFilenameViewController功能类似InternalResourceViewResolver，它将URL解释成视图例如："/index.html" -> "index" 

4、FlowController类似董事长（BP） 而下属flowExecutor 类似首席执行官（CEO），老大不需要自己亲自去弄，叫ceo传达一下就行

配置flow （为首席执行官配置资源和任务）

<?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:context="http://www.springframework.org/schema/context"      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/context       http://www.springframework.org/schema/context/spring-context-2.5.xsd    http://www.springframework.org/schema/webflow-config    http://www.springframework.org/schema/webflow-config/spring-webflow-config-2.0.xsd">    <webflow:flow-executor id="flowExecutor"/>  <webflow:flow-registry id="flowRegistry" flow-builder-services="flowBuilderServices"> <webflow:flow-location path="classpath:shopping.xml" id="shopping"/> <webflow:flow-location path="classpath:addToCart.xml" id="addToCart"></webflow:flow-location> </webflow:flow-registry>  <webflow:flow-builder-services id="flowBuilderServices" view-factory-creator="mvcViewFactoryCreator"/> <bean id="mvcViewFactoryCreator" class="org.springframework.webflow.mvc.builder.MvcViewFactoryCreator"> <property name="viewResolvers" ref="viewResolver"/> </bean> </beans>

总结：

1、webflow:flow-executor 就是默认首席执行官

2、分配的任务就是shopping.xml和addToCart.xml

3、工作流中需要渲染工作，这时候服务工作就交给了viewResolver

step3、配置工作流

欢迎页-》挑选商品-》加入购物-》计算总数量和总价格

shopping.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"    xsi:schemaLocation="http://www.springframework.org/schema/webflow       http://www.springframework.org/schema/spring-webflow-2.0.xsd">      <var name="mycart" class="com.jack.Cart"/>   <on-start>   <set name="conversationScope.cart" value="mycart"/>   </on-start>   <view-state id="viewCart" view="viewCart">    <on-render>   <evaluate expression="productService.getProducts()" result="viewScope.products"/>   </on-render>         <transition on="submit" to="viewOrder">          </transition>          <transition on="addToCart" to="addProductToCart"></transition>    </view-state>      <subflow-state id="addProductToCart" subflow="addToCart">    <transition on="productAdded" to="viewCart"/>    </subflow-state>    <view-state id="viewOrder" view="viewOrder">          <transition on="confirm" to="orderConfirmed">          </transition>      </view-state>      <view-state id="orderConfirmed" view="orderConfirmed">          <transition on="returnToIndex" to="returnToIndex">          </transition>      </view-state>      <end-state id="returnToIndex" view="externalRedirect:servletRelative:/index.jsp">      </end-state>       </flow>

addToCart.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"    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))"></evaluate>    <transition to="productAdded"/>    </action-state>    <end-state id="productAdded"/> </flow>

总结：

1、<var>表示定义变量，Cart就是购物车，就像你去超市购物，在入口推着购物车，每人一个

2、<on-start>表示开始时候准备好，conversationScope.cart （表示作用域，简单就是在整个一次购物中，这个购物车只会你使用）

3、<view-state>表示jsp显示的时候，告诉需要显示的view=“viewCart” 表示为viewCart.jsp

4、<on-render>表示在显示jsp的时候需要做一些事情，比如装置一些数据，类似在进商场之前，工作人员已经将货物上架，不然你买啥

5、<transition>表示接下一个步骤，类似你看到喜欢商品，需要做的一个动作就是将商品放入购物车，这里有两种情况，加入购物车还是不加入

6、不加入就去前台结账，如果加，这是需要增加加的动作,这里它增加一个字流程<subflow-state> 注意属性subflow="addToCart"

7、你会发现addToCart在shopping.xml，它在addToCart.xml, 注意它标签是<action-state>而不是<view-state> 它是一个动作而不是展示视图

8、添加完商品转到了productAdded,也就是shopping.xml这里来了，发现它又转到viewCart，它要更新商品数量和类型

9、假如，我们已经添加好了商品，点击submit, 它转到viewOrder,viewOrder展示你已经选择的商品

10、点击confirm表示你确认你购买的商品

11、最后重定向到externalRedirect:servletRelative:/index.jsp ，也就是首页

12、注意addToCart.xml定义requestScope.productId (表示在请求作用域中设置一个属性为productId ,它的值取自requestParameters.productId[本身请求的过来的数据])

13、xml如何实现java代码，使用SpEL ，也就是Spring Expression Language，例如expression="cart.addItem(productService.getProduct(productId))" 

总的来说就是它用xml画了一个流程图

步骤4、jsp文件

index.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body><h1>Hello!</h1><br><a href="shopping.do">ViewCart</a></body></html>

orderConfirmed.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body><h1>Order Confirmed</h1><br><a href="${flowExecutionUrl }&_evenId=returnToIndex">Return to index</a></body></html>

viewCart.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body>      <h1>View Cart</h1>       <h2>Items in Your Cart</h2>   <c:choose>   <c:when test="${empty cart.items}">   <p>Your cart is empty.</p>   </c:when>   <c:otherwise>   <table border="1" cellspacing="0">   <tr>   <th>Item</th>   <th>Quantity</th>   <th>Unit Price</th>   <th>Total</th>   </tr>   <c:forEach var="item" items="${cart.items }">   <tr>   <td>${item.product.descript }</td>   <td>${item.quantity }</td>   <td>${item.product.price }</td>   <td>${item.totalPrice }</td>   </tr>   </c:forEach>   <tr>   <td>Total:</td>   <td></td>   <td></td>   <td>${cart.totalPrice }</td>   </tr>   </table>   </c:otherwise>   </c:choose>    <a href="${flowExecutionUrl}&_eventId=submit">Submit</a>      <h2>Products for Your Choice</h2>    <table>    <c:forEach var="product" items="${products}">    <tr>    <td>${product.descript }</td>    <td>${product.price }</td>    <td><a href="${flowExecutionUrl}&_eventId=addToCart&productId=${product.id}">[add                          to cart]</a></td>    </tr>    </c:forEach>    </table></body></html>

viewOrder.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"    pageEncoding="UTF-8"%><%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>Insert title here</title></head><body>      <h1>Order</h1>    <c:choose>    <c:when test="${empty cart.items }">    <p>Your cart is empty.</p>    </c:when>    <c:otherwise>    <table border="1" cellspacing="0">    <tr>    <th>Item</th>    <th>Quantity</th>    <th>Unit Price</th>    <th>Total</th>    </tr>    <c:forEach var="item" items="${cart.items }">    <tr>    <td>${item.product.descript }</td>    <td>${item.quantity }</td>    <td>${item.product.price }</td>    <td>${item.totalPrice }</td>    </tr>    </c:forEach>    <tr>    <td>TOTAL:</td>    <td></td>    <td></td>    <td>${cart.totalPrice }</td>    </tr>    </table>    </c:otherwise>    </c:choose>      <a href="${flowExecutionUrl}&_eventId=confirm">Confirm</a>    </body>  </html>

总结：

1、flowExecutionUrl跳转处理控制器

2、_eventId 表示事件Id

java类：

Cart.java

package com.jack;import java.io.Serializable;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;public class Cart implements Serializable{/** *  */private static final long serialVersionUID = 2218144992574949101L;private Map<Integer, CartItem> map = new HashMap<Integer, CartItem>();public List<CartItem> getItems(){return new ArrayList<CartItem>(map.values());}//addItem 用于向购物车添加商品、public void addItem(Product product){int id=product.getId();CartItem item = map.get(id);if(item != null){item.increaseQuantity();}else{map.put(id, new CartItem(product,1));}}public int getTotalPrice(){int total =0;for (CartItem item : map.values()){total += item.getProduct().getPrice() * item.getQuantity();}return total;}}

CartItem.java

package com.jack;import java.io.Serializable;public class CartItem implements Serializable{/** *  */private static final long serialVersionUID = 7087013311725981757L;private Product product;//商品private int quantity; //数量public CartItem(Product product, int quantity) {super();this.product = product;this.quantity = quantity;}//计算该条目的总价格public int getTotalPrice(){return this.quantity*this.product.getPrice();}//增加商品的数量public void increaseQuantity(){this.quantity++;}public Product getProduct() {return product;}public int getQuantity() {return quantity;}public void setProduct(Product product) {this.product = product;}public void setQuantity(int quantity) {this.quantity = quantity;}}

Product.java

package com.jack;import java.io.Serializable;public class Product implements Serializable{/** *  */private static final long serialVersionUID = -3547488052308853185L;private int id;private String descript;private int price;public Product() {super();// TODO Auto-generated constructor stub}public Product(int id, String descript, int price) {super();this.id = id;this.descript = descript;this.price = price;}public int getId() {return id;}public String getDescript() {return descript;}public int getPrice() {return price;}public void setId(int id) {this.id = id;}public void setDescript(String descript) {this.descript = descript;}public void setPrice(int price) {this.price = price;}}

ProductService.java

package com.jack;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;import org.springframework.stereotype.Service;@Service("productService")public class ProductService {private Map<Integer, Product> products = new HashMap<Integer,Product>();public ProductService(){products.put(1, new Product(1, "Bulldog", 1000));products.put(2, new Product(1, "Chihuahua", 1000));products.put(3, new Product(1, "Labrador", 1000));}public List<Product> getProducts() {return new ArrayList<Product>(products.values());}public void setProducts(Map<Integer, Product> products) {this.products = products;}public Product getProduct(int productId){return products.get(productId);}}