Running a Servlet using Piranha is very easy and fun! For this blog entry we will show you how you can use Piranha Embedded, coupled with the DefaultHttpServer to run a HelloWorldServlet.
Follow steps mentioned below.
The code for the HelloWorldServlet will be similar to the snippet below.
package helloworld;
import jakarta.servlet.ServletException;
import jakarta.servlet.http.HttpServlet;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
public class HelloWorldServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws IOException, ServletException {
PrintWriter writer = response.getWriter();
writer.println("Hello World");
}
}
The code for the HelloWorldApplication class will be similar to the snippet below.
package helloworld;
import cloud.piranha.embedded.EmbeddedPiranha;
import cloud.piranha.embedded.EmbeddedPiranhaBuilder;
import cloud.piranha.http.impl.DefaultHttpServer;
import cloud.piranha.http.webapp.HttpWebApplicationServerProcessor;
public class HelloWorldApplication {
public static void main(String[] arguments) throws Exception {
EmbeddedPiranha piranha = new EmbeddedPiranhaBuilder()
.servlet("HelloWorld", HelloWorldServlet.class)
.servletMapping("HelloWorld", "/*")
.buildAndStart();
DefaultHttpServer server = new DefaultHttpServer(8080,
new HttpWebApplicationServerProcessor(piranha), false);
server.start();
}
}
Note you can swap out DefaultHttpServer with Grizzly, JDK HTTP server, Undertow or Netty. All it takes is using the appropriate module and adjusting the class name.
module helloworld {
exports helloworld;
requires cloud.piranha.embedded;
requires cloud.piranha.http.api;
requires cloud.piranha.http.impl;
requires cloud.piranha.http.webapp;
requires jakarta.servlet;
}
The POM file below contains the plumbing to build the project using Maven.
<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>embedded</groupId>
<artifactId>servlet-runner</artifactId>
<version>1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>Piranha Embedded Servlet runner application</name>
<properties>
<piranha.version>23.1.0</piranha.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>3.10.1</version>
<configuration>
<release>17</release>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.4.0</version>
<executions>
<execution>
<id>copy-dependencies</id>
<phase>prepare-package</phase>
<goals>
<goal>copy-dependencies</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/modules</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<version>3.0.0</version>
<configuration>
<mainClass>helloworld.HelloWorldApplication</mainClass>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>3.3.0</version>
<configuration>
<archive>
<manifest>
<mainClass>helloworld.HelloWorldApplication</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-resources-plugin</artifactId>
<version>3.3.0</version>
<executions>
<execution>
<id>copy-resources</id>
<phase>verify</phase>
<goals>
<goal>copy-resources</goal>
</goals>
<configuration>
<outputDirectory>${project.build.directory}/modules</outputDirectory>
<resources>
<resource>
<directory>${project.build.directory}</directory>
<filtering>false</filtering>
<includes>
<include>*.jar</include>
</includes>
</resource>
</resources>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.moditect</groupId>
<artifactId>moditect-maven-plugin</artifactId>
<version>1.0.0.RC1</version>
<executions>
<execution>
<id>create-runtime-image</id>
<phase>verify</phase>
<goals>
<goal>create-runtime-image</goal>
</goals>
<configuration>
<modulePath>
<path>${project.build.directory}/modules</path>
</modulePath>
<modules>
<module>helloworld</module>
</modules>
<launcher>
<name>helloworld</name>
<module>helloworld</module>
</launcher>
<noManPages>true</noManPages>
<noHeaderFiles>true</noHeaderFiles>
<compression>2</compression>
<outputDirectory>${project.build.directory}/jlink</outputDirectory>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>cloud.piranha</groupId>
<artifactId>piranha-embedded</artifactId>
<version>${piranha.version}</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>cloud.piranha.http</groupId>
<artifactId>piranha-http-impl</artifactId>
<version>${piranha.version}</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>cloud.piranha.http</groupId>
<artifactId>piranha-http-webapp</artifactId>
<version>${piranha.version}</version>
<scope>compile</scope>
</dependency>
</dependencies>
</project>
The next step is to build the JLink image.
mvn verify
And voila the jlink/target/jlink directory will contain
the JLink native image. You now have a quick recipe to write Servlets
using Piranha Embedded.
Enjoy!
Posted March 24th, 2023