sample.java

Turbine示例

import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.util.HashMap;
import java.util.Properties;

import java.io.IOException;
import java.io.FileNotFoundException;
import java.io.FileInputStream;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletConfig;

import org.apache.velocity.Template;
import org.apache.velocity.context.Context;
import org.apache.velocity.servlet.VelocityServlet;

import org.apache.velocity.app.Velocity;

import org.apache.velocity.exception.ResourceNotFoundException;
import org.apache.velocity.exception.ParseErrorException;

/**
 *   This is a working example that shows how to use 
 *   Velocity from a servlet.  Note that there is a little
 *   more code than the JavaWorld article showed - required
 *   for configuration.
 */
public class Sample extends VelocityServlet
{
    public Template handleRequest( HttpServletRequest request, 
                                   HttpServletResponse response, Context context )
    {
        /*
         * organize our data
         */

        ArrayList list = new ArrayList();
        Map map = new HashMap();

        map.put("name", "horse");
        map.put("price", "$100.00");
        list.add( map );

        map = new HashMap();
        map.put("name", "dog");
        map.put("price", "$59.99");
        list.add( map );

        map = new HashMap();
        map.put("name", "bear");
        map.put("price", "$3.99");
        list.add( map );

        /* 
         *  add that list to the context
         */
        
        context.put("petList", list);
        
        /*
         *  get the template 
         */

        Template template = null;

        try
        {
            template = getTemplate("petstoreemail.vm");
        }
        catch( Exception e )
        {
            System.out.println("Error from PetStore example Servlet " + e);
        }

        return template;
    }


    /**  
     *  Override the base class's loadConfiguration(), this will
     *  set the log file to be off of the webapp root, and
     *  will do the same with the file loader paths.  This 
     *  will fail in containers that don't support getRealPath()
     *  (this will be fixed in 1.3 relase with a new loader)
     */
   protected Properties loadConfiguration(ServletConfig config )
        throws IOException, FileNotFoundException
    {
        /*
         *  get our properties file and load it
         */

        String propsFile = config.getInitParameter(INIT_PROPS_KEY);
        
        Properties p = new Properties();
        
        if ( propsFile != null )
        {
            String realPath = getServletContext().getRealPath(propsFile);
        
            if ( realPath != null )
            {
                propsFile = realPath;
            }

            p.load( new FileInputStream(propsFile) );
        }

        /*
         *  first, normalize our velocity log file to be in the 
         *  webapp
         */

        String log = p.getProperty( Velocity.RUNTIME_LOG);

        if (log != null )
        {
            log = getServletContext().getRealPath( log );
            
            if (log != null)
            {
                p.setProperty( Velocity.RUNTIME_LOG, log );
            }
        }

       
        /*
         *  now, if there is a file loader resource path, treat it the
         *  same way.
         */

        String path = p.getProperty( Velocity.FILE_RESOURCE_LOADER_PATH );

        if ( path != null)
        {
            path = getServletContext().getRealPath(  path );

            if ( path != null)
            {
                p.setProperty( Velocity.FILE_RESOURCE_LOADER_PATH, path );
            }
        }

        return p;
    }  

}