I use spring to inject DemoService has always been null, there is no problem with the filter inject of servlet, in the class of extends TurboFilter, how can I get the DemoService object?
https://stackoverflow.com/questions/30662641/inject-spring-bean-into-custom-logback-filter
I have tried the answer to this connection and did not solve the problem of inject.
public class ErrorLogTurboFilter extends TurboFilter {
#Autowired
private DemoService demoService;
#Override
public FilterReply decide(Marker marker, Logger logger, Level level, String s, Object[] objects, Throwable throwable) {
// todo
return FilterReply.NEUTRAL;
}
}
Problem: Logback starts up before the Spring context. Therefore you need to lazy initialize the Filter with the to be injected bean. Apart from that the Filter will not be called as a Spring bean, but as a Turbofilter, that does not know any injections and so on.
What you could try is define that Filter as a Spring bean in your context, that contains the DemoService. Inject the bean via a Setter for the service, but declare the field static, so you are able to access it from the logging context.
Now during the execution you need to check if the static field is already initialized, if so you can use it without a problem.
You are not trying the answer you are quoting, because your extended filter "ErrorLogTurboFilter" does not have a "#Named("errorLogTurboFilter")" which is the standard annotation to make your filter a spring bean.
see : What is javax.inject.Named annotation supposed to be used for?
#markusw According to your prompt, this is my solution,and thank you.
#Configuration
public class WebConfig {
#Bean
public DemoService demoService() {
return new DemoService();
}
}
public class ErrorLogTurboFilter extends TurboFilter {
private ApplicationContext ctx = new AnnotationConfigApplicationContext(WebConfig.class);
private DemoService demoService = ctx.getBean(DemoService.class);
#Override
public FilterReply decide(Marker marker, Logger logger, Level level, String s, Object[] objects, Throwable throwable) {
// todo
return FilterReply.NEUTRAL;
}
}
Related
Is it possible to read property file values inside #Repository.
Any help is appreciated.
As M.Deinum mentioned in the comment section, #Repository is just a variation of #Component. You can read your property file by injecting Environment or you can just use #Value.
If you use a class repository, you can use the #Value annotation on any non-final field to have it populated automatically.
On the other hand, if you are using an interface repository, you cannot read a property directly, as you have nowhere to inject your components/values.
Anyway, I found a sort of work-around which can be used to achieve a similar result.
You start by creating a class that implements ApplicationContextProvider:
#Component
public class StaticPropertiesProvider implements ApplicationContextAware {
private static ApplicationContext applicationContext;
#Override
public void setApplicationContext(#Nonnull final ApplicationContext applicationContext) throws BeansException {
StaticPropertiesProvider.applicationContext = applicationContext;
}
public static <T> T getProperty(final String property, final Class<T> clazz) {
return applicationContext.getEnvironment().getProperty(property, clazz);
}
}
When your application starts, the static applicationContext field will be populated with your Application Context, so that you can use it afterwards from the static getProperties method.
You can then call it from a default method inside your repository, e.g.
public interface MyRepository extends MongoRepository<MyDocument, String> {
#Query(value = "{'myProperty': ?0}")
List<MyDocument> findByMyProperty(int myProperty);
default List<MyDocument> findByMyProperty() {
final var myPropertyDefault = StaticPropertiesProvider.getProperty("my.property", Integer.class);
return this.findByMyProperty(myProperty);
}
}
Clearly there should be a property name my.property with an int value inside application.properties.
(you can do the same even with JPA repositories)
I'm following a tutorial and they #Service a class which in my mind should make it available to the whole application.
Why are the #Autowire-ing the class in Application?
Application:
#Configuration
#EnableAutoConfiguration // todo why not #SpringBootApplication
#ComponentScan
public class QuoteAppWsApplication implements CommandLineRunner {
public static void main(String[] args) {
SpringApplication.run(QuoteAppWsApplication.class, args);
}
#Autowired
private EventBus eventBus; //
#Autowired // todo This is #Service...why is it be Autowired
private NotificationConsumer notificationConsumer;
NotificationConsumer:
#Service
public class NotificationConsumer implements Consumer<Event<NotificationData>> {
#Autowired
private NotificationService notificationService;
#Override
public void accept(Event<NotificationData> notificationDataEvent) { // .getData() belongs to Event<>
NotificationData notificationData = notificationDataEvent.getData(); //TODO Gets data from Event
try {
notificationService.initiateNotification(notificationData);
} catch (InterruptedException e) {
// ignore
}
}
}
#Service is a specialization of #Component. It is an annotation that tells Spring to include this class as a Bean in the Spring context. You can think of this as telling Spring what to pick up and put into the context during component scanning.
#Autowired is Spring's annotation to inject something from the context. You can think of this as you declaring what you want to get out of Spring. In general, you need to use this annotation on any field, constructor, or setter that you want Spring to invoke to supply you with the object that it's managing for the given type.
To answer your question, yes, you need both to declare what you want put into the context and when you want something out of the context.
Also, your first three annotations can be replaced with #SpringBootApplication. This annotation is a meta-annotation, meaning it's an annotation that it shorthand for including a series of other annotations. It's documented to include, among other things, all three of your annotations.
I am trying to autowire a component into a custom JsonDeserializer but cannot get it right even with the following suggestions I found:
Autowiring in JsonDeserializer: SpringBeanAutowiringSupport vs HandlerInstantiator
Right way to write JSON deserializer in Spring or extend it
How to customise the Jackson JSON mapper implicitly used by Spring Boot?
Spring Boot Autowiring of JsonDeserializer in Integration test
My final goal is to accept URLs to resources in different microservices and store only the ID of the resource locally. But I don't want to just extract the ID from the URL but also verify that the rest of the URL is correct.
I have tried many things and lost track a bit of what I tried but I believe I tried everything mentioned in the links above. I created tons of beans for SpringHandlerInstantiator, Jackson2ObjectMapperBuilder, MappingJackson2HttpMessageConverter, RestTemplate and others and also tried with setting the SpringHandlerInstantiator in RepositoryRestConfigurer#configureJacksonObjectMapper.
I am using Spring Boot 2.1.6.RELEASE which makes me think something might have changed since some of the linked threads are quite old.
Here's my last attempt:
#Configuration
public class JacksonConfig {
#Bean
public HandlerInstantiator handlerInstantiator(ApplicationContext applicationContext) {
return new SpringHandlerInstantiator(applicationContext.getAutowireCapableBeanFactory());
}
}
#Configuration
public class RestConfiguration implements RepositoryRestConfigurer {
#Autowired
private Validator validator;
#Autowired
private HandlerInstantiator handlerInstantiator;
#Override
public void configureValidatingRepositoryEventListener(ValidatingRepositoryEventListener validatingListener) {
validatingListener.addValidator("beforeCreate", validator);
validatingListener.addValidator("beforeSave", validator);
}
#Override
public void configureJacksonObjectMapper(ObjectMapper objectMapper) {
objectMapper.setHandlerInstantiator(handlerInstantiator);
}
}
#Component
public class RestResourceURLSerializer extends JsonDeserializer<Long> {
#Autowired
private MyConfig config;
#Override
public Long deserialize(JsonParser p, DeserializationContext ctxt) throws IOException, JsonProcessingException {
ServiceConfig serviceConfig = config.getServices().get("identity");
URI serviceUri = serviceConfig.getExternalUrl();
String servicePath = serviceUri.getPath();
URL givenUrl = p.readValueAs(URL.class);
String givenPath = givenUrl.getPath();
if (servicePath.equals(givenPath)) {
return Long.parseLong(givenPath.substring(givenPath.lastIndexOf('/') + 1));
}
return null;
}
}
I keep getting a NullPointerException POSTing something to the API endpoint that is deserialized with the JsonDeserializer above.
I was able to solve a similar problem by marking my deserializer constructor accept a parameter (and therefore removing the empty constructor) and marking constructor as #Autowired.
public class MyDeserializer extends JsonDeserializer<MyEntity> {
private final MyBean bean;
// no default constructor
#Autowired
public MyDeserializer(MyBean bean){
this.bean = bean
}
...
}
#JsonDeserialize(using = MyDeserializer.class)
public class MyEntity{...}
My entity is marked with annotation #JsonDeserialize so I don't have to explicitly register it with ObjectMapper.
I am writing a custom evaluator in which I want to autowire another bean. I am unable to do so as evaluator gets initialized by logger where as beans are initialized by spring context. Below is the sample of my code:
In logback-spring.xml:
<appender name="myAppender" class="ch.qos.logback.classic.net.SMTPAppender">
<evaluator class="com.package.CustomEvaluator">
<marker>FATAL</marker>
<interval>1000000</interval>
</evaluator>
</appender>
My custom evaluator:
#Slf4j
#Component
public class CustomEvaluator extends OnMarkerEvaluator {
#Autowired
private MyService myService;
#Override
public boolean evaluate(ILoggingEvent event) throws EvaluationException {
\\logic goes here
}
}
I am getting object of MyService always as null(which is expected). Is there any work around for this?
It don't think its possible because the Evaluator being an internal logback abstraction is not managed / initialized by spring, so obviously spring can't autowire anything into the evaluator.
In addition note, that logback gets initialized even before application context starts.
Of course you could provide some global holder class for the application context and set the context to it in the main method, and then get the reference to it in this evaluator, something like this:
public class ApplicationContextHolder {
private static ApplicationContext context;
// call it in main() method
public static void setContext(ApplicationContext ctx) {context = ctx;}
public static ApplicationContext getContext() {return context;}
}
class CustomEvaluator extends OnMarkerEvaluator {
public boolean evaluate(ILoggingEvent event) throws EvaluationException {
ApplicationContext ctx = ApplicationContextHolder.getContext();
if(ctx == null) {return false;} // not yet initialized / accessible
MyService myService = ctx.getBean(MyService.class);
}
}
But all-in-all I believe its a very ugly solution.
As a suggestion, I think you should consider refactoring of the logic so that the decision of whether to send an email based on logging event will be taken in the application (which is, I assume, spring boot driven so you have an access to the MyService)
Given the current implementation:
public foo() {
LOGGER.info("This should be sent by email");
}
I suggest a part of application:
#Component
public class MyLogic {
#Autowired MyService myService;
public void foo() {
if(myService.shouldSend()) {
LOGGER.info("This should be sent by email");
}
}
}
Is possible to get the proxy of a given object in Spring? I need to call a function of a subclass. But, obviously, when I do a direct call, the aspects aren't applied. Here's an example:
public class Parent {
public doSomething() {
Parent proxyOfMe = Spring.getProxyOfMe(this); // (please)
Method method = this.class.getMethod("sayHello");
method.invoke(proxyOfMe);
}
}
public class Child extends Parent {
#Secured("president")
public void sayHello() {
System.out.println("Hello Mr. President");
}
}
I've found a way of achieving this. It works, but I think is not very elegant:
public class Parent implements BeanNameAware {
#Autowired private ApplicationContext applicationContext;
private String beanName; // Getter
public doSomething() {
Parent proxyOfMe = applicationContext.getBean(beanName, Parent.class);
Method method = this.class.getMethod("sayHello");
method.invoke(proxyOfMe);
}
}
This hack is extremely awkward, please consider refactoring your code or using AspectJ weaving. You may feel warned, here is the solution
AopContext.currentProxy()
JavaDoc. I blogged about it here and here.
AopContext.currentProxy() as suggested by Tomasz will work. A more generic solution, that will work outside of the proxied class is to cast the object to org.springframework.aop.framework.Advised and get .getTargetSource().getTarget()
The former (getting the real object from the proxied object) is something that you should not really need. On the other hand getting the target proxy might be useful in some utility class that inspects existing beans in order to add some feature.
You can use a bean post-processor to set a reference to the proxy on the target bean. It moves the Spring-specifics from your beans to a single class.
Post-Processor
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
public class SelfReferencingBeanPostProcessor implements BeanPostProcessor {
#Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
return bean;
}
#Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
if (bean instanceof SelfReferencingBean) {
((SelfReferencingBean) bean).setProxy(bean);
}
return bean;
}
}
Context
Register the post-processor in applicationContext.xml.
<bean id="srbpp" class="SelfReferencingBeanPostProcessor"/>
Beans
Each bean must implement SelfReferencingBean to tell the post-processor that it needs a reference to the proxy.
public interface SelfReferencingBean {
void setProxy(Object proxy) ;
}
Now implement setProxy in each bean that needs to call itself through its proxy.
public class MyBean implements SelfReferencingBean {
MyBean proxy;
#Override
public void setProxy(Object proxy) {
this.proxy = (MyBean) proxy;
}
}
You could put this last bit of code into a bean base class if you don't mind casting proxy to bean's type when calling methods directly on it. Since you're going through Method.invoke you wouldn't even need the cast.
With a little work I bet this could be converted to an annotation processor a la #Autowired. Come to think of it, I don't recall if I even tried adding a self-reference using #Autowired itself.
public class MyBean implements SelfReferencingBean {
#Autowired MyBean proxy;
}