I want to use spring dependency injection for my domain classes, that are possibly not created within spring context. That's why I have annotated these classes with #Configurable annotation and I try to setup load time weaving. My spring configuration is :
#SpringBootApplication
#EnableSpringConfigured
#EnableAspectJAutoProxy
#EnableCaching(mode = AdviceMode.ASPECTJ)
#EnableLoadTimeWeaving
public class WebApplication extends WebMvcConfigurerAdapter
This works fine but only if my #Configurable classes are in same JAR as my main Spring Boot application. However I want to have my #Configurable domain classes in JAR that is added as dependency for main application.
I tried this but it looks like load time weaving is not working for external JARs. Do you have any suggestions how to solve this issue?
EDIT
I have added -verbose:class to my JVM options and I have found out that classes from external JARs are loaded by class loader before LoadTimeWeaving is configured and initialized. And classes not in external JAR are loaded as they are needed i.e. after LoadTimeWeaving init.
So basically my question is :
Is it possible to initialize LTW before external JARs loading? Or is it possible to reload (or make AspectJ enhancement) classes after LTW is configured?
EDIT 2
I found out the reason why my classes from external jar are loadded before LTW init. It's because these classes are also annotated with #Entity annotation. Therefore they are loaded during hibernate initialization which occure before LTW init.
So the final question is: :D
How to assume that LTW is initialized before hibernate (and possibly other) initializations?
Ok I have a solution. :) As I sad issue was the order of spring bean initialization. So I simple had to ensure that load time weaver was initialized before hibernate. Simply injecting LoadTimeWeaver into my configuration class was the workaround:
#Autowired
private LoadTimeWeaver loadTimeWeaver;
EDIT
Another solution is to add aspectjweaver.jar as javaagent in addition to spring-instrument.
Related
Caching Aspects are not having any effects at runtime with Spring Boot and Embedded tomcat with LoadTimeWeaving enabled,but we are seeing the weaving is happening fine in the logs.
Below is the configuration, the LoadTimeWeaving is enabled along with the mode as AspectJ for Caching
#Configuration
#EnableConfigurationProperties
#EnableSpringConfigured
#EnableAspectJAutoProxy(proxyTargetClass = true)
#EnableLoadTimeWeaving
#EnableTransactionManagement
#EnableAsync
#EnableCaching(mode = AdviceMode.ASPECTJ)
public class AppConfig {
}
Spring Agent
-javaagent:../../../spring-instrument-4.3.3.RELEASE.jar
Logs
[RestartClassLoader#2aaae670] debug weaving 'uk.co.loyalty.iss.newpro.reporting.domain.refdata.gateway.RestReferenceDataGateway'
[RestartClassLoader#2aaae670] weaveinfo Join point 'method-execution(java.util.List uk.co.loyalty.iss.newpro.reporting.domain.refdata.gateway.RestReferenceDataGateway.getHierarchyLevelDefns())' in Type 'uk.co.loyalty.iss.newpro.reporting.domain.refdata.gateway.RestReferenceDataGateway' (RestReferenceDataGateway.java:118) advised by around advice from 'org.springframework.cache.aspectj.AnnotationCacheAspect' (AbstractCacheAspect.aj:64)
[RestartClassLoader#2aaae670] weaveinfo Join point 'method-execution(java.util.Map uk.co.loyalty.iss.newpro.reporting.domain.refdata.gateway.RestReferenceDataGateway.getHierarchyLevelDefinitionMap())' in Type 'uk.co.loyalty.iss.newpro.reporting.domain.refdata.gateway.RestReferenceDataGateway' (RestReferenceDataGateway.java:129) advised by around advice from '**org.springframework.cache.aspectj.AnnotationCacheAspect**' (AbstractCacheAspect.aj:64)
[RestartClassLoader#2aaae670] **debug generating class** 'uk.co.loyalty.iss.newpro.reporting.domain.refdata.gateway.RestReferenceDataGateway$AjcClosure1'
[RestartClassLoader#2aaae670] debug generating class 'uk.co.loyalty.iss.newpro.reporting.domain.refdata.gateway.RestReferenceDataGateway$AjcClosure3'
there are whole bunch of discussions around this. The weaving is happening on the RestartClassLoader, not sure is it something to do with the class loader. Have also tried adding the below,
#Bean
public LoadTimeWeaver loadTimeWeaver() throws Throwable {
InstrumentationLoadTimeWeaver loadTimeWeaver = new InstrumentationLoadTimeWeaver();
return loadTimeWeaver;
}
Please provide your suggestions.
Edit
We need Aspectj mode as we are using caching on private methods. I removed the EnableAspectJAutoProxy but still that does not help.
On further analysis on the load time weaving, I noticed the below behaviour.
I profile the application and investigated on the class loaders to see the weaving is done correct for the caching annotation to work(classes are trasformed). I noticed for some classes in the classloader ,we have a class with suffix($AjcClosure and those are transformed classes after weaving is done). So, if cachinng annotations is part of those weaved classes, then it works fine.
Then I closely looked in to the classes why some classes are weaved correctly and some are not. Then I noticed that if classes are loaded already to the class-loader before weaving happens, then that is where the weaving is not happening.
#Bean
public IAService aService(){
return new AServiceImpl();
}
In the above case, the class is AServiceImpl is loaded to the class loader only when this instance is needed (after load time weaving and caching works perfectly).
But if the same class is being initialised using #Component then it is not getting weaved.
#Service
public class AServiceImpl{
}
I think, in the above case, the class AServiceImpl is loaded to the class loader while the spring container initialises and load time weaving is trying to weave after that).
I verified this behavior again in class loader as well. So, is it an issue if aspectj tries to weave a class that was already loaded. the same problem was raised in the Spring Jira as well in the below link.
https://jira.spring.io/browse/SPR-13786
As mentioned in the above link, if I pass the aspectj weaver as java agent like the below, then all the classes are being weaved correctly. So, is it required to have two agents or do we have any other option for this.
-javaagent:../../../aspectjweaver-1.6.1.jar
-javaagent:../../../spring-instrument-4.3.3.RELEASE.jar
Yes, the weaver needs to be active before the weaving targets are loaded by the classloader.
Now, I am an AspectJ geek but not a container geek, I mainly work with Java SE and no containers. Please try to also add
-javaagent:path/to/aspectjweaver.jar
to your command line and see if it helps.
I am writing a library to provide some functionality that is shared between multiple different Spring Boot applications that I work with.
I would like to do something similar to the auto-configuration that is provided by the many Spring Boot starter libraries exist. That, or some other simple declarative way to integrate my library with the ApplicationContext of the apps using it.
I have found some resources explaining how auto configuration works. I can figure out the above problem.
However, I have not been able to find any good examples of how I can test as part of my library's test suite that it suitably integrates with a Spring Boot application. Ideally, I would start up a simple Spring Boot app written in the library's test directly just for the sake of testing, add the right annotation to it, and be able to assert that the correct beans are then configured.
I have tried creating a TestApplication class that does that and writing integration tests using the SpringBootTest annotation but the TestApplication was never started before my test started.
What can I do to start up a simple app like that solely for the purpose of testing my library? My tests are written with Spock and Spock-Spring in case that changes things versus other test frameworks.
I was able to make it work with the following test class:
#SpringBootTest
#ContextConfiguration(classes = TestApplication)
class DummyIntegrationSpec extends Specification {
#Autowired
DummyService dummyService
void 'dummy service should exist'() {
expect:
dummyService.getMessage() == DummyConfiguration.MESSAGE
}
}
and this TestApplication class at src/test/groovy/com/example/project/TestApplication.groovy
#SpringBootApplication(scanBasePackages = 'com.example.project.config')
#EnableAutoConfiguration
class TestApplication extends SpringBootServletInitializer {
#Override
protected SpringApplicationBuilder configure(SpringApplicationBuilder application) {
return application.sources(TestApplication)
}
static void main(String[] args) {
SpringApplication.run(TestApplication, args)
}
}
The two key changes I had to make in order for the TestApplication to start and load the correct context when I moved my TestApplication class from src/main to src/test were:
the TestApplication class needed to be added to the ContextConfiguration annotation
the package that my library's Java config files live in needed to be added to the SpringBootApplication scanBasePackages field
The library auto-configuration does follow a similar structure to the one mentioned in the link tom provided.
Your auto-configuration should be automatically picked while your main spring application/test is starting and all beans will be registered in your context. They will be available for auto-wiring and follow your conditions and init order.
As a summary, make sure you have an auto-configuration annotated by #Configuration class with an #Import that imports your #Configuration annotated configuration classes (inside of them you define beans with methods annotated with #Bean). Also make sure you created a spring.factories file that include your auto-configuration class and that you removed the spring boot maven plugin (for the packaging to be right).
Also, make sure your auto-configuration project is NOT annotated by things like #SpringBootApplication, #EnableAutoConfiguration, #ComponentScan or other spring boot annotations that need to be only in the main spring boot projects (There should be one of them in each stack).
Please also see the article below:
Spring boot is based on a lot of pre-made auto-configuration parent projects. You should already be familiar with spring boot starter projects.
You can easily create your own starter project by doing the following easy steps:
Create some #Configuration classes to define default beans. You should use external properties as much as possible to allow customization and try to use auto-configuration helper annotations like #AutoConfigureBefore, #AutoConfigureAfter, #ConditionalOnBean, #ConditionalOnMissingBean etc. You can find more detailed information on each annotation in the official documentation Condition annotations
Place an auto-configuration file/files that aggregates all of the #Configuration classes.
Create a file named spring.factories and place it in src/main/resources/META-INF.
In spring.factories, set org.springframework.boot.autoconfigure.EnableAutoConfiguration property with comma separated values of your #Configuration classes:
org.springframework.boot.autoconfigure.EnableAutoConfiguration=
com.mycorp.libx.autoconfigure.LibXAutoConfiguration,
com.mycorp.libx.autoconfigure.LibXWebAutoConfiguration
Using this method you can create your own auto-configuration classes that will be picked by spring-boot. Spring-boot automatically scan all maven/gradle dependencies for a spring.factories file, if it finds one, it adds all #Configuration classes specified in it to its auto-configuration process.
Make sure your auto-configuration starter project does not contain spring boot maven plugin because it will package the project as an executable JAR and won't be loaded by the classpath as intended - spring boot will not be able to find your spring.factories and won't load your configuration
I am having a little weird behavior with my spring-data-mongo where my repository package is not being scanned by the <mongo:repositories/> tag. I am using spring 3.2.3.RELEASE with spring-data-mongo 1.2.1.RELEASE.
I have a project called edowmis and in it there are 2 maven modules, datalayer and web which a webapp.I am using the datalayer in isolation so the other module can be ignored. I have an application context for datalayer
So I wanted to test my setup by writing a small Unit/Integration test but I've noticed I can't autowire my UserRepository because It says there isn't such a bean
Since I am using IntelliJ I can see certain visuals when things are ok and not ok. I've addec <context:component-scan/> to my application context but no result.
But when I add the #Component annotation it has started identifying the Class.
all information you might need is on pastie.org
Is the #component or #Repository really necessary or something is wrong with my configuration?
Yes, the #Component or #Repository is necessary. The scan simply indicates that spring should look for classes identified via annotations (#Component, #Repository, #Service) and load them as beans. If you don't use repository or component scan, you would have to manually instantiate all spring-managed beans via XML configuration or Java configuration.
You have to tell spring which classes to turn into beans as it doesn't assume everything in the classpath is supposed to be a spring-managed bean, which is why you need to use the annotations.
I am new to springs. Is there an alternative for autowired to be used in a ordinary java bean which is not present in spring context.
You can do so by using Spring #Configurable with some AspectJ magic.
If you need a detailed explanation, here is the link.
And here is a brief overview of how it can be achieved.
First you have some bean that you want injected somewhere:
#Component
public class InjectedClass {
// ...
}
Then, you have a class that is not spring-container managed, that you want to instantiate. You want autowiring to work with this class. You mark it as a #Configurable.
#Configurable
public class NonContainerManagedClass {
#Autowired
private InjectedClass injected;
// ...
}
Now you need to tell spring that you want this non-container managed autowiring to work. So you put the following in your spring configuration.
<context:load-time-weaver />
<context:spring-configured />
Now, since this kind of thing requires modification of the bytecodes of your #Configurable class. So you tell Tomcat to use a different classloader. You can do so by creating a context.xml in your application's META-INF diretory and putting the following in there.
<Context path="/youWebAppName">
<Loader loaderClass="org.springframework.instrument.classloading.tomcat.TomcatInstrumentableClassLoader"
useSystemClassLoaderAsParent="false"/>
</Context>
Now, Tomcat needs to find that classloader. You can ensure that by putting Spring's spring-tomcat-weaver.jar (probably named org.springframework.instrument.tomcat-<version>.jar) in your tomcat installation's lib directory, and voila, the aspectj magic starts working. For classes that are annotated with #Configurable annotation, the #Autowired dependencies are resolved automatically; even if the instances are created outside of the spring-container.
This is probably the only way to make that work with Spring, in a clean manner. Make sure that you have appropriate dependencies in your classpath.
Another way would be to use the full AspectJ functionality and providing custom aspects around all your constructors and handling the dependency-injection yourself.
I've got an application which uses JAXRS to map Restlet resources using annotations. However, the only entry point I have is essentially defining a list of resource classes in the application configuration. These classes are instantiated by Restlet or JAXRS, so I have no way to put them in my ApplicationContext. Is there a way to have Spring scan the classpath and autowire new instances as necessary? I've already tried using something like below:
#Autowired
private SessionFactory sessionFactory;
Unfortunately, it doesn't really work. Is there a way to do what I'm talking about here?
You can use AspectJ to dependency inject your beans that are created out of your control, or if you create objects using new. You can read more on Springs documentation: http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/aop.html#aop-using-aspectj
Essentially what you will do is add #Configurable annotation to the class that you want to be target of injection. You also have to enable it in Spring by having in your Spring xml. Lastly you have to decide between compile time weaving or runtime weaving. Again you can get help from spring documentation.
Loadtime weaving: http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/aop.html#aop-aj-ltw
If you use maven you can check this Stackoverflow question for setting up compile time AspectJ: Why doesn't AspectJ compile-time weaving of Spring's #Configurable work?
ApplicationContext.getAutowireCapableBeanFactory().autowireBean(object) will inject all dependencies into the object.