@Cacheable and initialization during startup

Question

I would like to initialize all entries in cache during startup of my spring boot application (loading stuff from DB). Ideally, this is done before the application is already ready. So I implemented all loading in @PostConstruct. I remarked, that the cache is not already setup in @PostContruct and I followed some tips to do such initializations in the ApplicationReadyEvent. However, this still does not work as expected:

Even though I already call a @Cacheable Method in ApplicationReadyEvent, the second invocation re-enters the method instead of using the cache.

My Service:

@Service
public class MyService implements ApplicationListener<ApplicationReadyEvent {

  @Cacheable("entry")
  public List<String> getEntry() {
    System.out.println("getEntry called!");
    return Arrays.asList("aaa", "bbb");
  }

  @Override
  public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {
    System.out.println("*** onApplicationEvent");
    getEntry();
  }
}

My Caffeine CacheManager Config:

@Configuration
@EnableCaching
public class CachingConfig {

  @Bean
  public CacheManager cacheManager() {
    List<CaffeineCache> caffeineCaches = chacheList(Arrays.asList(
        "entry"
    ));

    SimpleCacheManager simpleCacheManager = new SimpleCacheManager();
    simpleCacheManager.setCaches(caffeineCaches);
    System.out.println("*** @Bean CacheManager");
    return simpleCacheManager;
  }

  private List<CaffeineCache> chacheList(List<String> cacheNames) {
    return cacheNames.stream().map(s -> new CaffeineCache(s, Caffeine.newBuilder().build()))
        .collect(Collectors.toList());
  }

}

A simple REST endpoint using the service:

@RestController
public class MyController {

  @Autowired
  MyService myService;

  @GetMapping("/test")
  public void test()
  {
    System.out.println("*** GET /test");
    myService.getEntry();
  }
}

If I start the application and perform two GET /test, I get the following output:

INFO 20120  --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 907 ms
*** @Bean CacheManager
INFO 20120  --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
INFO 20120  --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
INFO 20120  --- [           main] com.example.demo.DemoApplication         : Started DemoApplication in 1.639 seconds (JVM running for 2.473)
*** onApplicationEvent
*** getEntry called!
INFO 20120  --- [nio-8080-exec-1] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring DispatcherServlet 'dispatcherServlet'
INFO 20120  --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Initializing Servlet 'dispatcherServlet'
INFO 20120  --- [nio-8080-exec-1] o.s.web.servlet.DispatcherServlet        : Completed initialization in 4 ms
*** GET /test
*** getEntry called!
*** GET /test

So why does the second invocation of MyService.getEntry (i.e. the first invocation after "Startup") enters the code again?

At the end, I need a solution, which performs the first loading before the application finished to startup - i.e. I will try ContextRefreshedEvent or again @PostConstruct (and @Autowire CacheManager to have it configured before executing @PostConstruct). But the first step would be to get this example here behave as expected.

score 0 · Accepted Answer · answered Dec 14 '18 at 21:35

Ok, stupid error: in my service, the call to getEntry() must be done over proxy object rather than directly:

@Service
public class MyService implements ApplicationListener<ApplicationReadyEvent {

  @Autowired
  MyService self;

  @Cacheable("entry")
  public List<String> getEntry() {
    System.out.println("getEntry called!");
    return Arrays.asList("aaa", "bbb");
  }

  @Override
  public void onApplicationEvent(ApplicationReadyEvent applicationReadyEvent) {
    System.out.println("*** onApplicationEvent");
    self.getEntry();
  }
}

@Cacheable and initialization during startup

1 Answers1