CODEWITHSUNDEEP
javaspringspring-bootspring-mvc
chris
chris

Reputation: 2810

How does logging into the console works in the Java Spring framework

I have a very simple Spring application, but I can't not get a System.out.println statement to print into the console.

This is the main app file where I am printing an env variable set in a .yml file

import path.config.Config;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class MainApplication {

    @Autowired
    private Config config;

    public static void main(String[] args) {
        SpringApplication app = new SpringApplication(MainApplication.class);
        app.run();
    }

    public void run(String... args) throws Exception {
        System.out.println("env: " + config.getEnv());
    }

}

The configuration file looks like this:

import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableConfigurationProperties
@ConfigurationProperties
public class Config {
    private String env;

    public void setEnv(String env) {
        this.env = env;
    }

    public String getEnv() {
        return this.env;
    }
}

Finally the properties yml file

spring: 
    profiles.active: dev
    h2:
        console:
            enabled: true
---
spring:
    profiles: dev
env: dev
---
spring:
    profiles: test
env: test
---
spring:
    profiles: prod
env: prod

The Spring app builds a runs fine, however, I can't see the env variable to show in the terminal. I have seen examples of people using Controllers with a Request endpoint just to debug the environment variables in the browser. Is that the only option?

Upvotes: 0

Views: 306

Answers (1)

Ryuzaki L
Ryuzaki L

Reputation: 40078

Couple of changes to your code, you don't need to use new keyword for starting spring application, you can directly use static run method

 public static void main(String[] args) {
    SpringApplication.run(MainApplication.class);
  
}

Second thing the run method in MainApplication will only execute if that class implements CommandLineRunner

@SpringBootApplication
public class MainApplication implements CommandLineRunner {

    @Autowired
    private Config config;

    public static void main(String[] args) {
          SpringApplication.run(MainApplication.class);
    }

    public void run(String... args) throws Exception {
          System.out.println("env: " + config.getEnv());
     }

  }

Upvotes: 2

Related Questions