Sander_M Sander_M - 3 months ago 39
Java Question

What is the official spring boot way to start a simple non web based java application?

I am in the proces of converting a simple java project into a spring boot variant. The Spring Boot Reference Guide http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/ has been very helpful in general, but most examples of setting up a simple configuration involve some web based application. The getting started tutorial from https://spring.io/guides/gs/spring-boot/ tutorial doesn't provide the answer I am looking for either.

I have one class

HelloSpring
that I need to run one method on
printHello()
. I have configured the following classes, placed in the same package for simplicity:

Application.class

@SpringBootApplication
public class Application {

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

}


HelloConfiguration.class

@Configuration
public class HelloConfiguration {

@Bean
public HelloSpring helloSpring(){
HelloSpring hs = new HelloSpring();
hs.printHello();
hs.printHelloAgain();
return hs;
}

@Autowired
public HelloSpring hs;

}


HelloSpring.class

public class HelloSpring {

public void printHello() {
System.out.println("Hello Spring!");
}

@PostConstruct
public void printHelloAgain() {
System.out.println("Hello Spring?");
}

}


It prints (spring logging omitted):

Hello Spring!
Hello Spring?
Hello Spring?


However, I am unsure of the correct way to execute my HelloSpring class.

Given above example, what is the official way to wire and "run" a class when using spring boot?

Answer

Simply use the ApplicationContext that SpringApplication.run returns and then work with that. That's pretty much all that is required

public static void main(String[] args) {
    ApplicationContext context = SpringApplication.run(Application.class, args);
    HelloSpring bean = context.getBean(HelloSpring.class);
    bean.printHello();
}

So you can open a gui, etc. and use the ApplicationContext to get your beans, etc.

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