How to get Spring application startup time / duration in code

Question

When I start my Spring application, I can see the startup time in console (I am using IntelliJ IDEA).

For example, below log shows 13.427s startup time for the application.

2016-12-29 13:58:05.491     : Starting Application on 8DSXD72 with PID 14120 
2016-12-29 13:58:05.518     : Running with Spring Boot v1.4.1.RELEASE, Spring v4.3.3.RELEASE
2016-12-29 13:58:05.519     : The following profiles are active: LOCAL
2016-12-29 13:58:15.537     : JMX is disabled
....
2016-12-29 13:58:17.392     : Started Application in 13.427 seconds (JVM running for 14.71)

Is there a way to get this startup time in the code? I want to print out application startup time in Spring /info endpoint.

Answer 1

This answer is based on Sotirios's comment.

First, create a custom class which implements SpringApplicationRunListener.

package com.example;

public class AppListener implements SpringApplicationRunListener {
    public static long appStartTime;
    public static long appFinishTime;

    //Constructor is required.
    public AppListener(SpringApplication application, String[] args) {
    }

    @Override
    public void started() {
        appStartTime = System.currentTimeMillis();
    }

    @Override
    public void environmentPrepared(ConfigurableEnvironment environment) {

    }

    @Override
    public void contextPrepared(ConfigurableApplicationContext context) {

    }

    @Override
    public void contextLoaded(ConfigurableApplicationContext context) {

    }

    @Override
    public void finished(ConfigurableApplicationContext context, Throwable exception) {
        appFinishTime = System.currentTimeMillis();
    }
}

Then, add this line to spring.factories file.

org.springframework.boot.SpringApplicationRunListener=com.example.AppListener

Answer 2

Using ApplicationReadyEvent is less intrusive and minimal change.

@SpringBootApplication
public class TrackSpringBootTimeApp {
    private static Instant startTime;
    private static Instant endTime;

    public static void main(String[] args) {
        startTime = Instant.now();
        SpringApplication.run(TrackSpringBootTimeApp.class);
        System.out.println("Total time taken in start up " + 
        Duration.between(startTime, endTime).toString());
    }

    @EventListener(ApplicationReadyEvent.class)
    public void startApp() {
        endTime = Instant.now();
    }
}