Spring Cache in MVC - Possible to lookup with autowiring? - spring

Question

I see that when the application starts up my singleton cache is created
DEBUG Creating CGLIB proxy: target source is SingletonTargetSource for
target object [com.abc.xyz.util.CacheUtil#14e3dd3] DEBUG Unable to
apply any optimizations to advised method: public java.util.Map
But how do I lookup the value using autowiring as when I attempt, it does not hit the singleton created and creates a new instance of CacheUtil.
CacheUtil.java [This class is annotated with #Component]
public Map getSelectOptions(String codeType) {
System.out.println("Cache Breached!!!");
HashMap selectOpts = new HashMap();
Vector<MyTableDO> vCodeMap = null;
vCodeMap = MyTableDO.getCodesFromDatabase(codeType, "LookupCacheUtil");
if(vCodeMap == null || vCodeMap.size() == 0) return selectOpts;
vCodeMap.forEach(codeMap -> selectOpts.put(codeMap.getCodeValue(), codeMap.getCodeDesc()));
return selectOpts;
}
My spring config xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd">
<context:component-scan base-package="com.abc.xyz" />
<context:annotation-config />
<bean class="org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor"/>
<bean id="cacheUtil" class="com.abc.xyz.util.CacheUtil" />
</beans>
Class Invoking the Cached method
#Autowired
#Qualifier("cacheUtil")
protected CacheUtil cacheUtil;
public Map getSelectOptions(String codeType) {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(MyApplication.class);
//ctx.refresh();
CacheUtil lkp = (CacheUtil) ctx.getBean(CacheUtil.class);
ctx.close();
System.out.println("App Context lookupCacheUtil -"+lkp); // Not the same object of Spring Cache and comes to be new instance on every call
System.out.println("Autowired lookupCacheUtil -"+cacheUtil); // Always comes to be NULL
return lkp.getSelectOptions(codeType);
}
}
MyApplication class
#SpringBootApplication
#EnableCaching
public class MyApplication extends SpringBootServletInitializer{
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(MyApplication.class);
}
#Override
public void onStartup(ServletContext container) {
XmlWebApplicationContext context = new XmlWebApplicationContext();
context.setConfigLocation("/WEB-INF/config/spring-servlet.xml");
//using servlet 3 api to dynamically create spring dispatcher servlet
ServletRegistration.Dynamic dispatcher = container.addServlet("spring", new DispatcherServlet(context));
dispatcher.setLoadOnStartup(2);
dispatcher.addMapping("/");
}
public static void main(String[] args) {
SpringApplication.run(MyApplication.class, args);
}
}

Answer 1

On detailed analysis, my understanding of Autowired become more refined. Thanks to this link.
In my case, I had autowired 'CacheUtil' on a form bean. It appears that the form beans are not being managed by spring or at least in this case. The same autowired works normally in a controller which is managed by Spring.
So I to work around by fetching the Spring Cache 'Proxy' version of CacheUtil from the Application Context. Below code snippet should help (method getInstance()):
import org.springframework.beans.BeansException;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
#Component("MyCache")
public class CacheUtil implements ApplicationContextAware{
private static ApplicationContext appContext;
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
// TODO Auto-generated method stub
appContext = applicationContext;
}
/**
* Method to fetch the shared instance of the Spring Cache Object that helps reach the
* Cache that resides in Application Context.
*
* #return Singleton shared instance of the Spring Cache Proxy of this class CacheUtil
*/
public static CacheUtil getInstance() {
CacheUtil appCache = appContext.getBean("MyCache", CacheUtil.class);
if(appCache != null) return appCache;
return new CacheUtil();
}