了解Spring Boot @Autowired

当您init从类的构造函数调用该方法时App,Spring尚未将依赖项自动装入该App对象.如果要在Spring完成创建并自动装配App对象后调用此方法,则添加带@PostConstruct注释的方法来执行此操作,例如:

@SpringBootApplication
public class App {
    @Autowired
    public Starter starter;

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

    public App() {
        System.out.println("constructor of App");
    }

    @PostConstruct
    public void init() {
        System.out.println("Calling starter.init");
        starter.init();
    }
}