Use spring application as library in non-spring application

Question

I implemented spring-boot application and now I want to use it as a lib for non-spring application. How can I initialize lib classes so autowired dependencies work as expected?Obviously if I create class instance with 'new', all autowired dependencies will be null.

Answer 1

The theory is that you need to instantiate an application context for your Spring Boot dependency to live in, then extract a bean from there and make use of it.

In practice, in your Spring Boot dependency you should have an Application.java class or similar, in which a main method starts the application. Start by adding there a method like this:

public static ApplicationContext initializeContext(final String[] args) {
    return SpringApplication.run(Application.class, args);
}

Next step, in you main application, when you see fit (I'd say during startup but might as well be the first time you need to use your dependency) you need to run this code:

final String[] args = new String[0]; // configure the Spring Boot app as needed
final ApplicationContext context = Application.initializeContext(args); // createSpring application context
final YourBean yourBean = (YourBean)context.getBean("yourBean"); // get a reference of your bean from the application context

From here you can use your beans as you see fit.