I'm converting my guice application to a spring based on because of issues I found with the #transaction annotation. When doing so, I came to a issue with the configuration of a custom objectmapper with spring/resteasy. I want to register the hibernate4Module (fasterxml jackson) and a custom deserializer.
I have found many solution when using spring mvc, but I'm not using spring mvc.
I'm looking at the resteasyboostrap class, since there you have control over you factory, but I don't know how to register my new SimpleModule there.
Anyone with any experience? When I'm searching the internet, it seems nobody is trying to do the same thing. Perhaps I'm looking in the wrong places?
This one was eventually an easy one to fix.
Remove the resteasy-jackson provider and write a custom class that you annotate with the spring #Component annotation. Jax-RS picks up the provider and uses the object mapper in the provider.
I was searching in the implementation, but the answer was in the jax-rs api.
#Component
#Provider
#Consumes({"application/*+json", "text/json"})
#Produces({"application/*+json", "text/json"})
public class JacksonProvider extends JacksonJsonProvider {
public JacksonProvider() {
setMapper(new CustomObjectMapper());
}
}
Related
I have got a Class that converts Entity to DTO, class is mainly Mapper ConfigurableMapper from Orika packages. I have annotated the mapper class with #Component and Autowired it any class to convert from DTO to Mapper. This can be achieved without #Component and Autowiring.
Please enlighten me.
Consider using a ConverterFactory for Conversion
Baeldung wrote an article about it under:
spring-type-conversions
For some Reference:
docs.spring.io
An even more specific Implementation also from Baeldung:
Entity To DTO Conversion for a Spring REST API
I'm not sure if it is necessary to annotate #Component to helper/utility classes. As long as they don't need to be instantiated from spring as a bean you can delete the annotation.
I'm looking at code in which I'm assuming spring decides to use Jackson behind the scenes to auto convert an object to json for a #RestController
#RestController
#RequestMapping("/api")
public class ApiController {
private RoomServices roomServices;
#Autowired
public ApiController(RoomServices roomServices) {
this.roomServices = roomServices;
}
#GetMapping("/rooms")
public List<Room> getAllRooms() {
return this.roomServices.getAllRooms();
}
}
The Room class is just a plain java class with some fields, getters/setters. There is no Jackson or any other explicit serialization going on in the code. Although this does return json when checking the url. I tried looking through the spring documentation but I'm not quite sure what I'm looking for. What is the name for this process in spring / how does it work? I tried with just #Controller and it broke. Is this functionality coming from #RestController?
If you are using Spring Boot Starter Web, you can see that it's using Spring Boot Starter JSON through the compile dependencies, and Jackson is the dependency of the Start JSON library. So, you're assumption is right (Spring is using Jackson for Json convertion by default)
Spring use it's AOP mechanism to intercept the mapping methods in #Controller (you can see that #RestController is actually a #Controller with #ResponseBody), spring create a proxy object (using JDK proxy or through cglib) for the class that annotated with #Controller.
When the request flow is processing, the program who really call the mapping method will be lead to the proxy first, the proxy will invoke the real #Controller object's method and convert it's returning value to Json String using Jackson Library (if the method is annotated with #ResponseBody) and then return the Json String back to the calling program.
I've been searching for hours to find a solution for my problem but I can't get it to work. I want to inject my Weld-managed service into a ConstraintValidator that is used to validate a User-Object that is posted to my JAX-RS Rest-Service. Everything is deployed to a glassfish 4.1 server.
I have a Service like this
#ApplicationScoped
public class UserService {
}
and I want to inject it into a ConstraintValidator like this
public class UniqueUserNameValidator implements ConstraintValidator<UniqueUserName, ApiUser> {
#Inject
private UserService service;
#Override
public void initialize(UniqueUserName constraintAnnotation) {
}
#Override
public boolean isValid(ApiUser value, ConstraintValidatorContext context) {
return service.getByUserName(value.getUserName()) == null;
}
}
the REST resource looks like this
#Path("users")
#Produces(MediaType.APPLICATION_JSON)
public class UserResource {
#Inject
UserService userService;
#POST
public Response createUser(#Valid ApiUser apiUser) {
ApiRepresentation created = userService.create(apiUser);
return Response.created(createURL(created)).build();
}
}
When I Post a json user object i get the following exception:
org.glassfish.hk2.api.UnsatisfiedDependencyException: There was no object available for injection at SystemInjecteeImpl(requiredType=UserService,parent=UniqueUserNameValidator,qualifiers={},position=-1,optional=false,self=false,unqualified=null,173822971)
at org.jvnet.hk2.internal.ThreeThirtyResolver.resolve(ThreeThirtyResolver.java:74)
at org.jvnet.hk2.internal.Utilities.justInject(Utilities.java:947)
at org.jvnet.hk2.internal.ServiceLocatorImpl.inject(ServiceLocatorImpl.java:902)
at org.jvnet.hk2.internal.ServiceLocatorImpl.createAndInitialize(ServiceLocatorImpl.java:977)
at org.jvnet.hk2.internal.ServiceLocatorImpl.createAndInitialize(ServiceLocatorImpl.java:968)
at org.glassfish.jersey.internal.inject.Injections.getOrCreate(Injections.java:173)
I'm aware that jersey uses hk2 as DI provider and the ConstraintValidator is created using the InjectingConstraintValidatorFactory which in return uses the ResourceContext. Since HK2 doe know nothing about my WELD container managed beans it can not inject the proper service when creating the ConstraintValidator.
To fix this I am searching for
a) A way to provide JAX-RS (preferable a pure JAX-RS way without a dependency to jersey) with a custom ConstraintValidatorFactory to create the validator.
or
b) A way to force jersey to use WELD as the DI provider or tell hk2 to pickup all container managed beans WITHOUT manually adding every single bean to hk2.
I have no Idea how to use the bridge proposed here .
I appreciate any help.
Cheers
I also faced this issue with Jersey 2.25.x, Weld 2.4.x and Tomcat 8.x and haven't found a proper solution with #Inject.
As a workaround, I programmatically looked up for the bean instance using:
SomeSortOfBean bean = CDI.current().select(SomeSortOfBean.class).get();
Do you have the possibility to change the underlying JAX-RS implementation for your project?
When I had the same problem, I just switched from Jersey to RestEasy (fully certified JAX-RS implementation). http://resteasy.jboss.org/
Changing the implementation was easy enough: Just include the dependy through your favorite build automation tool (I use gradle):
compile 'org.jboss.resteasy:resteasy-servlet-initializer:3.0.11.Final'
Additionally, to make CDI work, include the resteasy-cdi JAX-RS CDI bridge:
compile 'org.jboss.resteasy:resteasy-cdi:3.0.11.
Lastly if you want the same JSON format, include the resteasy-jackson-provider:
compile 'org.jboss.resteasy:resteasy-jackson-provider:3.0.11.Final'
In the end, switching to resteasy gave me a lot less headache than trying to implement a Jersey fix.
To use jamon in spring, it's described to use JamonPerformanceMonitorInterceptor and put it to springs AOP-mechanism via a applicationContext.xml. It's explained, and there's an example within the tests in it's sources. Unfortunately, I want to build a spring-boot application without any xml-configuration.
Is it possible to use some annotations to include the JamonPerformanceMonitorInterceptor to spring?
Better late than never...
I had the very same situation: I needed to configure JAMon without any XML configuration. Most of the examples online (including the comments in the JAMon source code) advertise XML configuration flexibility, but I couldn't find any examples with annotation based configuration. Also annotation-based configs are not necessarily less flexible, they just need to be conceptually separated and not confused with functional parts of the application. I think such advisor can be a good example:
#Component
public class MonitoringAdvisor extends AbstractPointcutAdvisor {
private final StaticMethodMatcherPointcut pointcut = new StaticMethodMatcherPointcut() {
#Override
public boolean matches(Method method, Class<?> targetClass) {
return targetClass.isAnnotationPresent(RestController.class);
}
};
#Override
public Pointcut getPointcut() {
return this.pointcut;
}
#Override
public Advice getAdvice() {
return new JamonPerformanceMonitorInterceptor(true, true);
}
}
This advisor would let Spring/AOP know to run JAMon monitoring advice on any method of Spring bean annotated with #RestContrller. This advisor should be configured/added to the same Spring context as rest controllers.
Note, that in my case I specifically wanted to monitor my rest controllers. One can adapt the advisor according to his/her own needs. (In my code I use a more advanced/configurable version of the presented advisor)
Is this Spring Boot sample application helpful?
Here is the relevant part of the Spring AOP manual.
I'm using Spring 4 and was following the Rossen Stoyanchev's blog post about using websockets in Spring. I was able to get everything working but I'm not sure what the best way to use a custom object mapper when sending application/json.
I'm injecting a SimpMessageSendingOperations and calling convertAndSend. I'm not positive but I'm pretty sure I'm getting a SimpMessagingTemplate (it implements SimpMessageSendingOperations) which contains a setMessageConverter. This method takes a MessageConverter and there is a MappingJackson2MessageConverter class but of course it uses it's own internal ObjectMapper which cannot be redefined.
So what it looks like I have to do is create a custom MessageConverter and define my custom ObjectMapper within it so I can pass it to an instance of SimpMessagingTemplate that I can then inject into my classes.
This seems like it would work, but also more involved than I expected. Am I overlooking something?
Looks like it is possible, but will be made easier in Spring 4.0.1
See - https://jira.springsource.org/browse/SPR-11184
Quote from the bug report above.
In the mean time, with #EnableWebSocketMessageBroker setup you can:
remove the annotation
extend WebSocketMessageBrokerConfigurationSupport instead of implementing WebSocketMessageBrokerConfigurer
override brokerMessageConverter() method and remember to keep #Bean in the overriding method
Nowadays you can do it like this:
#Configuration
#EnableWebSocketMessageBroker
public class WebSocketConfig implements WebSocketMessageBrokerConfigurer {
#Override
public boolean configureMessageConverters(List<MessageConverter> messageConverters) {
MappingJackson2MessageConverter converter = new MappingJackson2MessageConverter();
// Avoid creating many ObjectMappers which have the same configuration.
converter.setObjectMapper(getMyCustomObjectMapper());
messageConverters.add(converter);
// Don't add default converters.
return false;
}
...
}
Unfortunately ObjectMapper cannot be given directly to MappingJackson2MessageConverter's constructor, meaning it will first create a useless ObjectMapper.