This page contains supplemental information to the Developing a Spring Framework MVC application step-by-step article by Thomas Risberg, showing the changes needed to use Velocity instead of JSP.

Part 1 - Basic Application and Environment Setup

Step 2 - index.jsp

Of course, we will be using Velocity, so let's name this file index.vm.

Step 4 - Test the application

Naturally, the URL is http://localhost:8080/springapp/index.vm

Step 6 - Modify web.xml in WEB-INF directory

web.xml : Change the welcome-file to...

  <welcome-file-list>
    <welcome-file>
      index.vm
    </welcome-file>
  </welcome-file-list>

Step 12 - Create a View

Again, this file will be hello.vm.

SpringappController.java : return the template.

    public ModelAndView handleRequest(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {

        logger.info("SpringappController - returning hello view");

        return new ModelAndView("hello.vm");
    }

Part 2 - Developing and Configuring the Application

Step 13 - Improve index.jsp

We won't be needing an include.vm, but let's make the springapp/war/WEB-INF/velocity directory anyways.

Add Velocity jar to springapp/war/WEB-INF/lib

web.xml : Change welcome file to hello.htm and add a servlet mapping to it

  <servlet-mapping>
    <servlet-name>springapp</servlet-name>
    <url-pattern>*.htm</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>springapp</servlet-name>
    <url-pattern>/hello.htm</url-pattern>
  </servlet-mapping>

  <welcome-file-list>
    <welcome-file>
      hello.htm
    </welcome-file>
  </welcome-file-list>

Now, we won't even need an index.vm. Thanks to Marcelo Bello for the post in bugzilla, and Maarten Bosteels for finding this. :)

Step 14 - Improve the view and the controller

Move the view hello.vm to the WEB-INF/velocity directory.

springapp/war/WEB-INF/velocity/hello.vm : Use VTL instead of JSTL

<p>Greetings, it is now ${now}

springapp/src/SpringappController.java : Change the view to WEB-INF/velocity/hello.vm.

        return new ModelAndView("WEB-INF/velocity/hello.vm", "now", now);

Those of the impatient ones should now be wondering, "How come the ${now} doesn't get replaced by the time?". That is because Spring does not know of Velocity yet. So, we'll need to go ahead and add Velocity settings to the springapp-servlet.xml.

springapp/war/WEB-INF/springapp-servlet.xml : Add Velocity settings

    <bean id="velocityConfig" class="org.springframework.web.servlet.view.velocity.VelocityConfigurer">
        <property name="resourceLoaderPath">
            <value>/</value>
        </property>
    </bean>

    <bean id="viewResolver" class="org.springframework.web.servlet.view.velocity.VelocityViewResolver">
    </bean>

Now, you should be able to see the same screen.

Step 15 - Decouple the view and the controller

From this step, the Controller class is the same for JSP and Velocity. Isn't that wonderful?

springapp/war/WEB-INF/springapp-servlet.xml

    <bean id="viewResolver" class="org.springframework.web.servlet.view.velocity.VelocityViewResolver">
        <property name="prefix"><value>/WEB-INF/velocity/</value></property>
        <property name="suffix"><value>.vm</value></property>
    </bean>

Step 17 - Modify the view to display business data and add support for message bundle

springapp/war/WEB-INF/velocity/hello.vm : VTL instead of JSTL

<html>
<head><title>#springMessage("title")</title></head>
<body>
<h1>#springMessage("heading")</h1>
<p>#springMessage("greeting") ${model.now}
</p>
<h3>Products</h3>
#foreach ($prod in ${model.products})
  ${prod.description} <i>${prod.price}</i><br><br>
#end
</body>
</html>

In order to enable the Spring Velocimacros, we need to set the "exposeSpringMacroHelpers" property to "true" for org.springframework.web.servlet.view.velocity.VelocityViewResolver.

springapp/war/WEB-INF/springapp-servlet.xml

    <bean id="viewResolver" class="org.springframework.web.servlet.view.velocity.VelocityViewResolver">
        <property name="prefix"><value>/WEB-INF/velocity/</value></property>
        <property name="suffix"><value>.vm</value></property>
        <property name="exposeSpringMacroHelpers"><value>true</value></property>
    </bean>

Part 3 - Adding Unit Tests and a Form to the Application

Step 22 - Adding a form

As we are using Velocity, we won't need to add the taglib entry to web.xml.

springapp/war/WEB-INF/jsp/priceincrease.vm : Use VTL

<html>
<head><title>#springMessage("title")</title></head>
<body>
<h1>#springMessage("priceincrease.heading")</h1>
<form method="post">
  <table width="95%" bgcolor="f8f8ff" border="0" cellspacing="0" cellpadding="5">
    <tr>
      <td alignment="right" width="20%">Increase (%):</td>
      #springBind("priceIncrease.percentage")
        <td width="20%">
          <input type="text" name="percentage" value="${status.value}">
        </td>
        <td width="60%">
          <font color="red">${status.errorMessage}</font>
        </td>
    </tr>
  </table>
  <br>
  #springBind("priceIncrease.*")
  #if(${status.error})
    <b>Please fix all errors!</b>
  #end
  <br><br>
  <input type="submit" alignment="center" value="Execute">
</form>
<a href="#springUrl("/hello.htm")">Home</a>
</body>
</html>

springapp/war/WEB-INF/jsp/hello.vm : Use VTL

<br>
<a href="#springUrl("/priceincrease.htm")">Increase Prices</a>
<br>

A few things to note about the Spring Velocimacro.

Part 4 - Implementing Database Persistence

Nothing to change. :)

VelocityAndSpringStepByStep (last edited 2010-10-03 13:59:59 by FauxFaux)