Create a WebSocket application
If you are looking to use Piranha Servlet with WebSockets then you landed at the right spot!
In 4 steps you will learn how to use WebSockets on Piranha Servlet. They are:
- Create the Maven POM file
- Add the ChatEndpoint.java file
- Deploy the application
- Test the application
Create the Maven POM file
Create an empty directory to store your Maven project. Inside of that directory
create the pom.xml
file with the content as below.
<?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>cloud.piranha.guides.servlet</groupId>
<artifactId>websocket</artifactId>
<version>1-SNAPSHOT</version>
<packaging>war</packaging>
<name>Piranha Servlet - WebSocket Chat application</name>
<properties>
<jakarta.websocket.version>2.1.0</jakarta.websocket.version>
<java.version>17</java.version>
<maven-compiler-plugin.version>3.11.0</maven-compiler-plugin.version>
<maven-war-plugin.version>3.3.2</maven-war-plugin.version>
<piranha.distribution>servlet</piranha.distribution>
<piranha.version>23.6.0</piranha.version>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
</properties>
<dependencies>
<dependency>
<groupId>jakarta.websocket</groupId>
<artifactId>jakarta.websocket-api</artifactId>
<version>${jakarta.websocket.version}</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>jakarta.websocket</groupId>
<artifactId>jakarta.websocket-client-api</artifactId>
<version>${jakarta.websocket.version}</version>
<scope>provided</scope>
</dependency>
</dependencies>
<build>
<finalName>websocket</finalName>
<plugins>
<plugin>
<groupId>cloud.piranha.maven.plugins</groupId>
<artifactId>piranha-maven-plugin</artifactId>
<version>${piranha.version}</version>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<release>${java.version}</release>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<version>${maven-war-plugin.version}</version>
<configuration>
<failOnMissingWebXml>false</failOnMissingWebXml>
</configuration>
</plugin>
</plugins>
</build>
</project>
Add the ChatEndpoint.java file
Add the ChatEndpoint.java file in the src/main/java/chat
directory.
package chat;
import jakarta.websocket.OnMessage;
import jakarta.websocket.Session;
import jakarta.websocket.server.ServerEndpoint;
@ServerEndpoint("/chat")
public class ChatEndpoint {
@OnMessage
public String onMessage(String message, Session session) {
return message;
}
}
Deploy the application
To deploy your application you will need 2 pieces.
- The Piranha Servlet runtime JAR.
- The WAR file you just produced.
For the WAR file see the target
directory. For the Piranha Servlet
distribution go to Maven Central. And then the following command line will
deploy your application:
java -jar piranha-dist-servlet.jar --war-file websocket.war
Test the application
To test the application connect to ws://localhost:8080/websocket/chat
using
a WebSocket client.
Conclusion
As you can creating a WebSocket application using Piranha Servlet is quite easy!