Running a standalone HTTP server with Jetty

JettyServer.java

import java.util.ArrayList;
import java.util.List;

import org.mortbay.jetty.Connector;
import org.mortbay.jetty.Server;
import org.mortbay.jetty.handler.HandlerList;
import org.mortbay.jetty.handler.ResourceHandler;
import org.mortbay.jetty.nio.SelectChannelConnector;
import org.mortbay.jetty.servlet.ServletHandler;
import org.mortbay.jetty.servlet.ServletHolder;
import org.mortbay.jetty.servlet.ServletMapping;

/** Starts a Jetty Server.
 * Serves all servlets registered with registerServlet.
 * Also Serves the static content in the current working directory.
 * 
 * Usage: 
 * JettyServer.init();
 * JettyServer.registerServlet(foo.CommentingServlet.class, "/c/*");
 * JettyServer.start();
 */
public class JettyServer {

  /** Tests the server */
  public static void main(String[] args) throws Exception {
    
    JettyServer.init();
    
//    TestServlet contains (the class must be public)
//    public class TestServlet extends HttpServlet {
//      @Override
//      protected void doGet(HttpServletRequest req, HttpServletResponse resp)
//          throws ServletException, IOException {
//        resp.getWriter().write(new Date().toString());}
//    }
    JettyServer.registerServlet(TestServlet.class, "/date");
    JettyServer.start();
  }
  
  // all Jetty objects required to start
  private static final SelectChannelConnector connector = new SelectChannelConnector();
  private static final Server server = new Server();
  private static final HandlerList mainHandler = new HandlerList();
  private static int port = 8080;
  private static ServletHandler servletHandler = new ServletHandler();
  
  // local lists storing the servlets
  private static final List<ServletHolder> holders = new ArrayList<ServletHolder>();
  private static final List<ServletMapping> mappings = new ArrayList<ServletMapping>();

  // protocol bits
  private static boolean initAlreadyCalled = false;
  
  /** Initializes the server */
  public static void init() throws Exception {
    if (initAlreadyCalled) {
      throw new RuntimeException("init() already called");
    }
    
    // init config
    connector.setPort(port);
    Connector[] c = { connector };
    server.setConnectors(c);

    // serving static files
    // "./src/JettyServer.java" is accessible at "http://localhost:8080/src/JettyServer.java"
    ResourceHandler resourceHandler = new ResourceHandler();
    resourceHandler.setResourceBase("./");
    
    // recall that Jetty takes into account
    // the first handler which matches the requested URI    
    mainHandler.addHandler(resourceHandler);
    mainHandler.addHandler(servletHandler);    
    server.setHandler(mainHandler);

    initAlreadyCalled = true;
  }

  /** Starts the server */
  public static void start() throws Exception {
    if (!initAlreadyCalled) {
      throw new RuntimeException("init() must be called before start()");
    }
    servletHandler.setServlets(holders.toArray(new ServletHolder[0]));
    servletHandler.setServletMappings(mappings.toArray(new ServletMapping[0]));
    server.start();
  }
  
  /** Registers a servlet in the server on the given path.
   * Example: registerServlet(foo.CommentingServlet.class, "/c/*");
   * */
  public static void registerServlet(Class servlet, String path) {
    if (!initAlreadyCalled) {
      throw new RuntimeException("init() must be called before registerServlet()");
    }
    ServletHolder holder = new ServletHolder();
    holder.setName(servlet.getName());
    holder.setClassName(servlet.getName());
    holders.add(holder);
    ServletMapping mapping = new ServletMapping();
    mapping.setPathSpec(path);
    mapping.setServletName(servlet.getName());
    mappings.add(mapping);
  }


}

TestServlet.sjava

import java.io.IOException;
import java.util.Date;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class TestServlet extends HttpServlet {
  @Override
  protected void doGet(HttpServletRequest req, HttpServletResponse resp)
      throws ServletException, IOException {
    resp.getWriter().write(new Date().toString());}
}

Translated to Scala...:

package org.dorest.server
package servlet

import java.util.ArrayList;
import java.util.List;

import java.io.IOException;
import java.util.Date;

import org.mortbay.jetty.Connector;
import org.mortbay.jetty.Server;
import org.mortbay.jetty.handler.HandlerList;
import org.mortbay.jetty.handler.ResourceHandler;
import org.mortbay.jetty.nio.SelectChannelConnector;
import org.mortbay.jetty.servlet.ServletHandler;
import org.mortbay.jetty.servlet.ServletHolder;
import org.mortbay.jetty.servlet.ServletMapping;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**

• After the start go to: "http://localhost:8080/date"
  */
  class JettyServer
  object JettyServer extends App {

  // all Jetty objects required to start
  val connector = new SelectChannelConnector();
  val server = new Server();
  val mainHandler = new HandlerList();
  val port = 8080;
  val servletHandler = new ServletHandler();

  // local lists storing the servlets
  val holders = new ArrayListServletHolder;
  val mappings = new ArrayListServletMapping;

  // protocol bits
  var initAlreadyCalled = false;

  /** Initializes the server */
  def init() {
  if (initAlreadyCalled) {
  throw new RuntimeException("init() already called");
  }

  connector.setPort(port);
  server.setConnectors(Array.apply[Connector](connector));
  
  val resourceHandler = new ResourceHandler();
  resourceHandler.setResourceBase("./");
  
  // recall that Jetty takes into account
  // the first handler which matches the requested URI    
  mainHandler.addHandler(resourceHandler);
  mainHandler.addHandler(servletHandler);
  server.setHandler(mainHandler);
  
  initAlreadyCalled = true;
  

  }

  /** Starts the server */
  def start() {
  if (!initAlreadyCalled) {
  throw new RuntimeException("init() must be called before start()");
  }
  servletHandler.setServlets(holders.toArray(new ArrayServletHolder));
  servletHandler.setServletMappings(mappings.toArray(new ArrayServletMapping));
  server.start();
  }

  def registerServlet(servlet: java.lang.Class[_], path: String) {
  if (!initAlreadyCalled) {
  throw new RuntimeException("init() must be called before registerServlet()");
  }
  val holder = new ServletHolder();
  holder.setName(servlet.getName());
  holder.setClassName(servlet.getName());
  holders.add(holder);
  val mapping = new ServletMapping();
  mapping.setPathSpec(path);
  mapping.setServletName(servlet.getName());
  mappings.add(mapping);
  }

  init();
  registerServlet(classOf[TestServlet], "/date");
  start();

}

class TestServlet extends HttpServlet {
override def doGet(req: HttpServletRequest, resp: HttpServletResponse) {
resp.getWriter().write(new Date().toString());
}
}