Change default Port of Spring Boot application from frontend with thymeleaf

Question

Is it possible to change the spring boot port from the frontend (by using thymeleaf) over a Endpoint on a @Controller?

And how can i programatically restart the application with the new configured port?

Answer 1

As stated here , you can set the server port like this:

import org.springframework.boot.web.server.ConfigurableWebServerFactory;
import org.springframework.boot.web.server.WebServerFactoryCustomizer;
import org.springframework.stereotype.Component; 

@Component
public class AppCustomContainer 
  implements WebServerFactoryCustomizer<ConfigurableWebServerFactory> {

  @Override
  public void customize(ConfigurableWebServerFactory factory) {
  
   factory.setPort(1234);
  
  }
}

Instead of 1234, you can use a file to store the port (when changing it) and load it when starting

After that, you can restart the application as described here :

• Add actuator and spring-cloud:

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter</artifactId>
    <version>2.0.0.RELEASE</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

• Enable restarting in the application.properties : management.endpoint.restart.enabled = true
• Add an the instance of RestartEndpoint :

@Autowired
private RestartEndpoint restartEndpoint;

And run this in order to restart:

Thread restartThread = new Thread(restartEndpoint::restart);
restartThread.setDaemon(false);
restartThread.start();