View source for Jetty/Tutorial/Jetty and Maven HelloWorld

{{Jetty Tutorial
| introduction =

[http://maven.apache.org/ Apache Maven] is a software project management and comprehension tool. Based on the concept of a project object model (POM), Maven can manage a project's build, reporting and documentation from a central piece of information. It is an ideal tool to build a web application project and such projects can use the [[Jetty/Feature/Jetty Maven Plugin]] to run the web application in development mode.

Maven can be used both to build embedded jetty appliations and standards based webapplications.

| details = 

To understand the basic operations of building and running against jetty, first review:
* the [[Jetty/Tutorial/Jetty_HelloWorld|Jetty HelloWorld Tutorial]].
* the [[Jetty/Tutorial/Embedding Jetty|Embedding Jetty Tutorial]].


== Embedded Jetty with Maven ==

Maven uses convention over configuration, so it is best to use the project structure as recommended by maven. Archetypes can be used to quickly setup maven projects, but for this tutorial, we will setup the structure manually:
<source lang="bash">
mkdir JettyMavenHelloWorld
cd JettyMavenHelloWorld
mkdir -p src/main/java/org/example
</source>

=== The HelloWorld class ===
Use an editor to create the file <tt>src/main/java/org/example/HelloWorld.java</tt> with the following contents:
<source lang="java">
package org.example;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletException;
import java.io.IOException;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.handler.AbstractHandler;

public class HelloWorld extends AbstractHandler
{
    public void handle(String target,
                       Request baseRequest,
                       HttpServletRequest request,
                       HttpServletResponse response) 
        throws IOException, ServletException
    {
        response.setContentType("text/html;charset=utf-8");
        response.setStatus(HttpServletResponse.SC_OK);
        baseRequest.setHandled(true);
        response.getWriter().println("<h1>Hello World</h1>");
    }

    public static void main(String[] args) throws Exception
    {
        Server server = new Server(8080);
        server.setHandler(new HelloWorld());
 
        server.start();
        server.join();
    }
}
</source>

=== The POM descriptor ===
The <tt>pom.xml</tt> file declares the project name and it's dependencies. Use and editor to create the file <tt>pom.xml</tt> with the following contents:
<source lang="xml">
<project xmlns="http://maven.apache.org/POM/4.0.0" 
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

  <modelVersion>4.0.0</modelVersion>
  <groupId>org.example</groupId>
  <artifactId>hello-world</artifactId>
  <version>0.1-SNAPSHOT</version>
  <packaging>jar</packaging>
  <name>Jetty HelloWorld</name>

  <dependencies>
    <dependency>
      <groupId>org.eclipse.jetty</groupId>
      <artifactId>jetty-server</artifactId>
      <version>7.0.1.v20091125</version>
    </dependency>
  </dependencies>

  <build>
    <plugins>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.1</version>
        <executions>
          <execution><goals><goal>java</goal></goals></execution>
        </executions>
        <configuration>
          <mainClass>org.example.HelloWorld</mainClass>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>
</source>

=== Building and Running embedded HelloWorld ===
The HelloWorld class can now be compiled and executed with the commands
<source lang="bash">
mvn clean compile exec:java
</source>
You can point your browser to [http://localhost:8080 http://localhost:8080] to see the hello world page.  You can observe what maven is doing for you behind the scenes by using the <tt>mvn dependency:tree</tr> command which reveals the transitive dependency resolved and downloaded as:
<source lang="text">
> mvn dependency:tree
[INFO] Scanning for projects...
[INFO] Searching repository for plugin with prefix: 'dependency'.
[INFO] ------------------------------------------------------------------------
[INFO] Building Jetty HelloWorld
[INFO]    task-segment: [dependency:tree]
[INFO] ------------------------------------------------------------------------
[INFO] [dependency:tree {execution: default-cli}]
[INFO] org.example:hello-world:jar:0.1-SNAPSHOT
[INFO] \- org.eclipse.jetty:jetty-server:jar:7.0.1.v20091125:compile
[INFO]    +- javax.servlet:servlet-api:jar:2.5:compile
[INFO]    +- org.eclipse.jetty:jetty-continuation:jar:7.0.1.v20091125:compile
[INFO]    \- org.eclipse.jetty:jetty-http:jar:7.0.1.v20091125:compile
[INFO]       \- org.eclipse.jetty:jetty-io:jar:7.0.1.v20091125:compile
[INFO]          \- org.eclipse.jetty:jetty-util:jar:7.0.1.v20091125:compile
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESSFUL
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 4 seconds
[INFO] Finished at: Tue Feb 16 16:19:08 EST 2010
[INFO] Final Memory: 11M/68M
[INFO] ------------------------------------------------------------------------
</source>



== Standard Web app with Jetty and Maven ==

The above example shows how a hello world example can be run as an embedded jetty handler. The following example shows how a standard webapp can be developed with maven and jetty.  The maven structure first needs to be created:

<source lang="bash">
mkdir JettyMavenHelloWarApp
cd JettyMavenHelloWebApp
mkdir -p src/main/java/org/example
mkdir -p src/main/webapp/WEB-INF
</source>

=== Creating some static content ===
A web application can contain static content, so create the file <tt>src/main/webapp/index.html</tt> with the following content:
<source lang="html">
<h1>Hello World Webapp</h1>
<a href="/hello">Hello Servlet</a>
</source>



}}