Intro
In my previous post I was playing with Velocity and the Spring framework. In this post I will show how to build a Velocity layout. Then I will inform Spring to use our layout when rendering a view.
Let’s build the layout
<html>
<body>
<div>
#parse ("head.vm")
</div>
<div>
$screen_content
</div>
<div>
#parse ("foot.vm")
</div>
</body>
</html>
The $screen_content variable is used by the VelocityLayoutViewResolver to include the result of an other VM in the layout. Let’s name this template.vm. Take a look at the content of the head.vm and foot.vm files.
I'm the header.
I'm the footer.
What are we showing?
I’ll show what I know about the X-Men and the Avenger. So I need a VM that will show some rosters from the X-Men and a VM that will show some rosters from the Avenger. Take a look at the content of the xmen.vm and the anvenger.vm files.
#foreach ($xmen in $xmens)
$xmen<br />
#end
#foreach ($avenger in $avengers)
$avenger<br />
#end
We need some controllers too
The XmenController provides some names for the X-Men’s crew and the AvengerController provides some names for the Avenger’s crew.
/**
* Knows a little about the X-Men.
*
* @author Sébastien Ayotte
*
*/
final class XmenController extends ParameterizableViewController {
@Override
protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception {
List<String> xmens = new ArrayList<String>();
xmens.add("Professor X");
xmens.add("Cyclops");
xmens.add("Iceman");
xmens.add("Archangel");
xmens.add("Beast");
xmens.add("Phoenix");
Map<String, List<String>> model = new HashMap<String, List<String>>();
model.put("xmens", xmens);
return new ModelAndView(getViewName(), model);
}
}
/**
* Knows a little about the Avenger.
*
* @author Sébastien Ayotte
*
*/
final class AvengerController extends ParameterizableViewController {
@Override
protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response) throws Exception {
List<String> avengers = new ArrayList<String>();
avengers.add("Thor");
avengers.add("Iron Man");
avengers.add("Henry Pym");
avengers.add("Wasp");
avengers.add("Hulk");
Map<String, List<String>> model = new HashMap<String, List<String>>();
model.put("avengers", avengers);
return new ModelAndView(getViewName(), model);
}
}
We need to configure the Spring context
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd">
<bean id="velocityConfig" class="org.springframework.web.servlet.view.velocity.VelocityConfigurer">
<property name="resourceLoaderPath" value="/WEB-INF/mods/core/sample/velocity/" />
</bean>
<bean id="viewResolver" class="org.springframework.web.servlet.view.velocity.VelocityLayoutViewResolver">
<property name="viewClass" value="org.springframework.web.servlet.view.velocity.VelocityLayoutView" />
<property name="layoutUrl" value="template.vm" />
<property name="cache" value="true" />
<property name="prefix" value="" />
<property name="suffix" value=".vm" />
</bean>
<bean name="/core/sample/velocity/showxmens.do" class="sample.velocity.XmenController">
<property name="viewName" value="xmen" />
</bean>
<bean name="/core/sample/velocity/showavengers.do" class="sample.velocity.AvengerController">
<property name="viewName" value="avenger" />
</bean>
</beans>
Try it!
I’m using Tomcat to deploy my application. I can now call http://localhost:8080/sample/core/sample/velocity/showxmens.do to have a list of the X-Men’s crew or I can call http://localhost:8080/sample/core/sample/velocity/showavengers.do to get a list of the Avenger’s crew. The two lists will be shown in the layout we define previously.
Sébastien's Coding Journey 