簡單的SpringWebFlow例子及遇到的問題

這段時間在看《Spring 實戰》里面有講Spring Web Flow，覺得里面的例子過於復雜，不適合新手，於是在網上找了個例子，跟着寫

以下是項目的目錄，我是基於maven搭建項目的

 

pom.xml文件，插入依賴

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>SpringWebFlow</groupId>
  <artifactId>SpringWebFlow</artifactId>
  <packaging>war</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>SpringWebFlow Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <!--SpringMVC所需要的依賴-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-beans</artifactId>
      <version>4.3.7.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>4.3.7.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-core</artifactId>
      <version>4.3.7.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>4.3.7.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>4.3.7.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-expression</artifactId>
      <version>4.3.7.RELEASE</version>
    </dependency>
    <!--Spring Web Flow所需要的依賴-->
    <dependency>
      <groupId>org.springframework.webflow</groupId>
      <artifactId>spring-binding</artifactId>
      <version>2.4.4.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.webflow</groupId>
      <artifactId>spring-faces</artifactId>
      <version>2.4.4.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.webflow</groupId>
      <artifactId>spring-js</artifactId>
      <version>2.4.4.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.webflow</groupId>
      <artifactId>spring-js-resources</artifactId>
      <version>2.4.4.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.webflow</groupId>
      <artifactId>spring-webflow</artifactId>
      <version>2.4.4.RELEASE</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>servlet-api</artifactId>
      <version>2.5</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>


  </dependencies>

</project>

 

Spring的配置文件

<?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: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">

    <!-- 創建流程執行器，默認表示引用bean id為 'flowRegistry'的流程注冊表-->
    <webflow:flow-executor id="flowExecutor" flow-registry="flowRegistry"/>

    <!-- 注冊流程注冊表 -->
    <webflow:flow-registry id="flowRegistry">
        <webflow:flow-location path="/WEB-INF/flows/hello.xml" id="hello" />
    </webflow:flow-registry>
    
    <!--作用：幫助DispatcherServlet將流程請求發送給Spring Web Flow-->
    <bean class="org.springframework.webflow.mvc.servlet.FlowHandlerMapping">
        <property name="flowRegistry" ref="flowRegistry"/>
    </bean>

    <!--作用：等同於controller,它會響應發送的流程請求並對其進行處理-->
    <bean id="flowHandlerAdapter" class="org.springframework.webflow.mvc.servlet.FlowHandlerAdapter">
        <property name="flowExecutor" ref="flowExecutor"/>
    </bean>
    
</beans>

此時流程注冊表和jsp文件在同一個文件夾下面，所以不需要配置視圖解析器和視圖工廠

 

web.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         id="WebApp_ID" version="3.1">
  <servlet>
    <servlet-name>FlowServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>
        classpath:spring-wf.xml
      </param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>FlowServlet</servlet-name>
    <url-pattern>*.flow</url-pattern>
  </servlet-mapping>
</web-app>

 

流程注冊表

<?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">
    <view-state id="cart" >
        <transition on="submit" to="order">
        </transition>
    </view-state>
    <view-state id="order">
        <transition on="confirm" to="finish">
        </transition>
    </view-state>
    <view-state id="finish">
        <transition on="toindex" to="index">
        </transition>
    </view-state>
    <end-state id="index" view="externalRedirect:index.jsp">
    </end-state>
</flow>

<view-state>，如果只有id屬性的時候，會在流程文件所在的文件夾尋找id名字的jsp文件作為view。如果明確指定view屬性的話，就找這個名字的jsp文件

 

各種jsp文件

index.jsp

<%--
  Created by IntelliJ IDEA.
  User: I am master
  Date: 2017/5/2
  Time: 14:43
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
      <h2 align="center">Hello，WebFlow</h2><br/>
      Item1:<a href="hello.flow">加入購物車</a><br/>
      Item2:<a href="hello.flow">加入購物車</a><br/>
      Item2:<a href="hello.flow">加入購物車</a>
</body>
</html>

cart.jsp

<%--
  Created by IntelliJ IDEA.
  User: I am master
  Date: 2017/5/2
  Time: 14:43
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
       <h2 align="center">購物車</h2><br/>
       衣服:<a href="${flowExecutionUrl}&_eventId=submit">買買買!!!</a><br/>
       褲子:<a href="${flowExecutionUrl}&_eventId=submit">買買買!!!</a><br/>
       鞋子:<a href="${flowExecutionUrl}&_eventId=submit">買買買!!!</a>
</body>
</html>

order.jsp

<%--
  Created by IntelliJ IDEA.
  User: I am master
  Date: 2017/5/2
  Time: 14:45
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
      <h2 align="center">訂單</h2><br/>
      <a href="${flowExecutionUrl}&_eventId=confirm">確認支付</a>
</body>
</html>

finish.jsp

<%--
  Created by IntelliJ IDEA.
  User: I am master
  Date: 2017/5/2
  Time: 14:45
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
      <h2 align="center">確認支付</h2><br/>
      <a href="${flowExecutionUrl}&_eventId=toindex">恭喜你，支付成功..</a>
</body>
</html>

 

運行結果

 

 

 

 

 

遇到的問題：

自己寫完以后，運行不起來，報404

 表達式沒有解析，一開始以為是缺少jar包，胡亂加了很多不必要的jar包，但是還是沒有解決

 錯誤原因:maven搭建項目web.xml文件默認的版本是2.3，但是我們需要的是3.1,因此將web.xml改為3.1的版本就可以了

 

很多情況下，我們會將流程注冊表和jsp放在不同的文件夾下，這就需要視圖解析器和視圖工廠

則Spring的配置文件應該為如下

<?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">  
      
    <!-- 流程注冊器 隱含一句 flow-registry="flowRegistry"   
        默認表示引用bean id為 'flowRegistry'的流程注冊表-->  
    <webflow:flow-executor id="flowExecutor" />  
      
    <!-- 流程注冊表 -->  
    <webflow:flow-registry id="flowRegistry" flow-builder-services="flowBuilderServices">  
        <webflow:flow-location path="/WEB-INF/flows/hello.xml" id="hello" />  
    </webflow:flow-registry>  
      
    <!-- WebFlow 視圖解析器 -->     
    <bean id="flowViewResolver"  
        class="org.springframework.web.servlet.view.InternalResourceViewResolver">  
         <property name="viewClass"  
            value="org.springframework.web.servlet.view.JstlView">  
        </property>  
        <property name="prefix" value="/WEB-INF/flowView/">  
        </property>  
        <property name="suffix" value=".jsp">  
        </property>   
    </bean>  
      
    <!-- WebFlow 視圖工廠構建服務 -->  
    <webflow:flow-builder-services id="flowBuilderServices" view-factory-creator="mvcViewFactoryCreator" />  
      
    <!-- WebFlow 視圖工廠創建器，表示使用視圖解析器將流程配置(xml)中的邏輯視圖交給視圖解析器解析 → jsp -->  
    <bean id="mvcViewFactoryCreator" class="org.springframework.webflow.mvc.builder.MvcViewFactoryCreator">  
        <property name="viewResolvers" ref="flowViewResolver" />  
    </bean>  
      
    <!-- 配置WebFlow 處理器映射器-->  
    <bean class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">  
        <property name="mappings">  
            <props>  
                <!-- 這個邏輯視圖名的 前綴 必須與流程注冊表中的  
                    webflow:flow-location 的 id一致，  
                    而 后綴 必須是當前DispatcherServlet匹配的地址,也就是  
                    必須以.flow結束,否則不被前端控制器處理(視圖名必須匹配*.flow)  
                 -->  
                <!-- 這里代表將請求路徑為hello.flow的url交給flowController處理 -->  
                <prop key="hello.flow">flowController</prop>  
            </props>  
        </property>  
    </bean>  
      
    <!--WebFlow 處理器，根據邏輯視圖名到流程執行器中找到對應的注冊表，進而找到流程配置文件，轉到不同的物理視圖-->  
    <!--主要工作就是負責將url轉化成邏輯視圖交給視圖解析器解析 → jsp-->  
    <bean id="flowController" class="org.springframework.webflow.mvc.servlet.FlowController">  
        <property name="flowExecutor" ref="flowExecutor" />  
    </bean>  
</beans>  

 

 

小結：

相同點：SpringMVC和流程都實現了mvc設計模式

不同點：在mvc設計模式的實現方面不同

SpringMVC通過編寫controller,service類來實現

而流程則通過bean來實現，底層已經幫你實現了，幫你來處理請求跳轉到對應的視圖界面