Step 1: DOWNLOAD JARS : Download velocity binaries from velocity website http://velocity.apache.org, we will need velocity-dep.jar from the zip (for example velocity-1.7-dep.jar)
Step 2: CREATE TEMPLATE : Create a helloworld.vm file and save it into a folder lets say D:/VMtemplates/. Following is the code that goes in the helloworld,vm file.
<html><head>Hello $header</head><body>Hello $name! Welcome to Velocity!</body></html>
Step 3: PROGRAM TO USE ABOVE TEMPLATE : Finally create create a main class(HelloWorlf.java) which uses the above template and generates a html file dynamically:
package hello.world;
import java.io.File;
import java.io.FileWriter;
import java.io.StringWriter;
import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.Template;
import org.apache.velocity.VelocityContext;
public class HelloWorld
{
public static void main( String[] args )throws Exception
{
VelocityEngine ve = new VelocityEngine();
ve.addProperty(“file.resource.loader.path”, “D:/VMtemplates/“);
// next, get the Template
Template t = ve.getTemplate( “helloworld.vm” );
// create a context and add data
VelocityContext context = new VelocityContext();
context.put(“name”, “API LEVEL”);
context.put(“header”, “My Header”);
// now render the template into a StringWriter
StringWriter writer = new StringWriter();
t.merge( context, writer );
// get the html text
String filecontent =writer.toString();
File htmlfile = new File(“D:/VMtemplates/heloworld.html”);
if(!htmlfile.exists()){
htmlfile.createNewFile();
}
FileWriter fw = new FileWriter(htmlfile);
fw.write(filecontent);
fw.close();
}
}
The important line is indicated by blue text color also the path marked in bold above are important.
NOTE: that this is a very basic code for getting stated with Velocity Template Engine. Do read further.
Further Reading:
http://velocity.apache.org/engine/devel/webapps.html
http://velocity.apache.org/engine/devel/developer-guide.html
{apilevel.com} 