Use of applicationreadyevent

about ApplicationReadyEvent, The explanation on the official website is ： Events are released as late as possible , To indicate that the application is ready to service the request . The source of this event is SpringApplication In itself , But pay attention to modifying its internal state , Because then all initialization steps will be completed . As the name suggests, it is SpringApplication Events after readiness , We can put some operations that may have class uninitialized exceptions into it to execute

@Component
public class BackendReadyEventListener implements ApplicationListener<ApplicationReadyEvent> {
    

    private static final Logger LOGGER = LoggerFactory.getLogger(BackendReadyEventListener.class);

    @Value("${thread.pool.coreSize:5}")
    private int corePoolSize;
    @Value("${thread.pool.maxSize:50}")
    private int maxPoolSize;

    @Override
    public void onApplicationEvent(ApplicationReadyEvent event) {
    
        // Profile database cache initialization 
        ConfigHelper configHelper = SpringContextUtils.getBean(ConfigHelper.class);
        configHelper.initDatabaseCache();
        // Initializes the thread pool 
        new PoolExecutor(corePoolSize, maxPoolSize, new ThreadPoolExecutor.AbortPolicy());
    }
}

such as , In the above code, I have performed operations such as initializing the configuration file database cache and initializing the thread pool