Harshal Shah- Technically Uncomplicating: Velociy Pratical Example

Download velocity-tools-2.0-src
Add the following jars in WEB-INF/lib folder of tomcat
velocity-1.6.2.jar
velocity-tools-view-2.0.jar
commons-beanutils-1.7.0.jar
commons-collections-3.2.jar
commons-digester-1.8.jar
commons-lang-2.2.jar
commons-logging-1.1.jar
oro-2.0.8.jar

Create a project simple inside webapps using eclipse

1.Inside simple folder create index.jsp

<%@taglib prefix="velocity" uri="http://velocity.apache.org/velocity-view" %>

<html>
<body>

I'm a JSP file that uses the VelocityViewTag.

<velocity:view>
#if( $XHTML )
#set( $br = "<br />" )
#else
#set( $br = "<br>" )
#end

$br
$br

Here we use a custom tool: $toytool.message

$br
$br

Lets count : #foreach($i in [1..5])$i #end

$br
$br

Let's play with a hashmap:$br
first add foo: $map.put("foo",$foo)$br
then add bar: $map.put("bar",$bar)$br
$br
and that gives us $map

$br
$br

Here we get the date from the DateTool: $date.medium

$br
$br

#if( $isSimple )
This is simple#if( $XHTML ) xhtml#end app version ${version}.
#end

$br
$br

Click <a href="index.vm">here</a> to see this VTL markup as a normal template.

</velocity:view>
</body>
</html>

2. Create index.vm file inside the simple folder

<html>
<body>

I'm a velocity template processed using the VelocityViewServlet.

#if( $XHTML )
#set( $br = "<br />" )
#else
#set( $br = "<br>" )
#end

$br
$br

Here we use a custom tool: $toytool.message

$br
$br

Lets count : #foreach($i in [1..5])$i #end

$br
$br

Let's play with a hashmap:$br
first add foo: $map.put("foo",$foo)$br
then add bar: $map.put("bar",$bar)$br
$br
and that gives us $map

$br
$br

Here we get the date from the DateTool: $date.medium

$br
$br

#if( $isSimple )
This is simple#if( $XHTML ) xhtml#end app version ${version}.
#end

$br
$br

Click <a href="index.jsp">here</a> to see the VelocityViewTag handle the same VTL markup.

</body>
</html>

3. In src under WEB-INF folder place class file

public class ToyTool
{
    private String message = "Hello from ToyTool!";

    public String getMessage()
    {
        return message;
    }

    public void setMessage(String m)
    {
        message = m;
    }

    /** To test exception handling in templates. */
    public boolean whine() {
        throw new IllegalArgumentException();
    }

}

4. Web.xml

<web-app>
<servlet>
    <servlet-name>velocity</servlet-name>
    <servlet-class>org.apache.velocity.tools.view.VelocityViewServlet</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>velocity</servlet-name>
    <url-pattern>*.vm</url-pattern>
</servlet-mapping>
<welcome-file-list>
    <welcome-file>index.vm</welcome-file>
</welcome-file-list>
</web-app>

5. Beside web.xml create a file tools.xml

<?xml version="1.0"?>

<tools>
    <data type="boolean" key="xhtml" value="true"/>
    <data type="boolean" key="isSimple" value="true"/>
    <data type="number" key="version" value="2.0"/>
    <data key="foo">this is foo</data>
    <data key="bar">this is bar.</data>
    <toolbox scope="request">
        <tool key="toytool" class="ToyTool" restrictTo="index*"/>
    </toolbox>
    <toolbox scope="session">
        <tool key="map" class="java.util.HashMap"/>
    </toolbox>
</tools>

In lib folder place the jar files mentioned above...start tomcat and try accessing the index.jsp

If you want a working example send me a mail at harshal.shah1982@gmail.com

Harshal Shah- Technically Uncomplicating

Thursday, January 27, 2011

Velociy Pratical Example

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