Is it possible to autowire beans using the #Autowired annotation without using component scanning?
Yes. <context-component-scan .. /> is responsible for discovering beans annotated with #Component, #Controller, #Service, #Respository, etc.
In order to have annotations processed (#Autowired, #Resource, etc) you need <context:annotation-config />. Thus annotations are processed on beans that are listed in applicationContext.xml.
As far as I know, <context-component-scan .. /> activates <context:annotation-config /> automatically.
This is true for both spring 2.5 and 3.0. (thanks skaffman)
I have never tried without component-scanning enabled, however I can confirm that #Autowire annotations works in Spring 3.0.x even with beans that are defined via XML.
When using AnnotationConfigApplicationContext, annotation config processors are always registered, meaning that any attempt to disable them at the #ComponentScan level would be ignored.
If it is meant in the question that you should explicitly state:
- <context:component-scan ...> in your xml file(it enables <context:annotation-config />)
or
- #ComponentScan in your java config
Then the answer is - Yes, it is possible to enable component scanning without any of the stated above statements in your code or xml file.
Another approach is to use AnnotationConfigApplicationContext :
AnnotationConfigApplicationContext context=
new AnnotationConfigApplicationContext("org.example.your.package");
Where "org.example.your.package" is your package for stereotyped annotated classes: #Component, #Repository, #Service, etc.
AnnotationConfigApplicationContext will search for your beans in the base package and inner packages.
No, we must use #ComponentScan if you are using java based configuration
(or) <context-component-scan .. /> for xml based configuration.
Note: If you are not using any of the approaches no corresponding instances are created in AplicationContext.
and when you try to access a resource (http://localhost:8080/customers) will end up with
WARNING: No mapping found for HTTP request with URI [/customers] in
DispatcherServlet with name 'dispatcher
Related
When specifying the XML configuration below:
<aop:aspectj-autoproxy>
<aop:include name="myBean" />
</aop:aspectj-autoproxy>
We all know that the #EnableAspectJAutoProxy annotation is the equivalent to the aspectj-autoproxy XML configuration but is there a java-based annotation equivalent for the aop:include XML configuration? I searched extensively and could not find.
Normally you tell Spring that you are using a particular feature, like Transaction management and it will create the proxies needed.
For instance #EnableTransactionManagement will cause Spring to create proxies for Components (services, controllers and repositories) which use #Transactional, you don't need to declare this, Spring automatically finds the beans that need to be proxied.
It works the same way with #EnableScheduling causing Spring to detect #Scheduled methods, and #EnableCaching to detect #Cached method.
I have a project where I need to bootstrap #Configuration java-config classes into the XML configuration.
To do that, I'm reading that I also need to include the following bean definition (along with the bean definitions of the classes annotated with #Configuration).
<bean class="org.springframework.config.java.process.ConfigurationPostProcessor" />
But, I end up receiving the following error:
Caused by: java.lang.ClassNotFoundException: org.springframework.config.java.process.ConfigurationPostProcessor
I have to assume I'm missing a jar somewhere, but my various web searches hasn't resulted in an answer yet. Any help would be greatly appreciated. Thanks.
EDIT: Evidently, I was reading old documentation, which is no longer current. Let me back up. My project contains older XML-based configuration. The newer code is all using 'Java-config'. With that said, the contexts are apparently completely separate. I'd like to 'import' a java-config class into the XML configuration, so that both contexts have those particular beans. Does anyone know how I can do that?
This actually ended up being fairly simple. To get a Java-config bean definition into the xml-config, simply define the Java-config class as a bean within the XML-config. There are no extra jars necessary.
#Configuration
public class SomeJavaConfig {
#bean
... [bean definition]
}
inside the XML-config, you define this class as a bean.
<!-- needed to pick up the annotated java-config -->
<context:annotation-config />
<!-- Importing java-config class, which are annotated with #Configuration -->
<bean name="SomeJavaConfig" class="[fully qualified path].SomeJavaConfig" />
The XML-config, which may be part of a different context, now has all the bean definitions defined within the JavaConfig class.
UPDATED - to included Alan Franzoni's comment below in the answer.
Alternatively to annotation-config you can use component-scan. Then you do not have to include the Configuration Bean in XML:
<context:component-scan base-package="[fully qualified package path]" />
See Difference between <context:annotation-config> vs <context:component-scan> for more details.
Should be in:
spring-javaconfig-<version>.jar
I've created a custom annotation (in Spring 3.05) that works great. I'd like to take that code and make it part of a library, packaged in a jar file, so I don't have to include my custom annotation code in each web app I write.
I'm unable to get Spring to act on the annotation, however. My library jar is in my web app's classpath and I tried scanning for it in applicationContext.xml:
<context:component-scan base-package="my.annotation.pkg" />
The field annotated with my custom annotation continues to be null.
Ideally I'd like to this to just work with a minimum of fuss and configuration, but so far I haven't had any success.
What part of Spring's wiring am I missing to get my custom annotation recognized when it's part of an external library?
Update
Here is how I "solved" it...just had to read a little more closely. In each context file (i.e. applicationContext.xml, dispatch-servlet.xml) I added the line:
<bean class="my.annotation.CustomInjector" />
...where my CustomInjector implements BeanPostProcessor. I based this on the code at this blog post: Implementing Seam style #Logger injection with Spring.
The author says I needed to do exactly what I did, so bad on me for not reading thoroughly. Why, though, is adding that bean definition required? Maybe Spring annotations are configured similarly under the hood - I just don't get why having the jar file on the classpath isn't enough.
Is your custom annotation annotated with the #Component annotation? From the Spring reference manual:
By default, classes annotated with #Component, #Repository, #Service, #Controller, or a custom annotation that itself is annotated with #Component are the only detected candidate components.
Alternatively, you could add a custom include-filter to the component-scan element in your XML configuration.
In order to use the #Autowire annotation, the object where you use the annotation must come from the spring context.
JSF managed beans are created by JSF's IOC not Springs, therefor i cannot use #Autowire inside of them must must use faces-config.xml and managed properties.
I already setup an EL resolver that lets be have spring beans as managed properties, i want to take it one step further and get rid of the need to go into the faces-config.xml every time i need to autowire something. Is this possible?
Just annotate your managed beans with #Controller (or #Component), and #Scope("request") (or session) and add <context:component-scan> (if you haven't), and managed beans will automatically be detected as spring beans. And since you are already using the ELResolver, that should be it - you should be able to use #Autowired (or better - #Inject, if using spring 3.0).
You can use #ManagedProperty(#{'someBean'}) for autowire other beans in jsf bean
I am moving from an xml config to annoations. i want to convert a session scoped bean that is
<aop:scoped-proxy>
can this be done with annotations, and if not, what can i do to still keep that declaration working?
edit:
I am interested in doing this in Spring 2.5
In Spring 3.0 it can be specified by the proxyMode attribute of #Scope annotation:
#Scope(value = "session", proxyMode = ScopedProxyMode.INTERFACES)
in the spring context xml, do something like:
<context:component-scan base-package="com.startup.failure" scoped-proxy="interfaces" />
Note that you would need to write interfaces for all classes in that package, though.
In Spring 2.5.x
If I do in spring-context.xml something like
<context:component-scan base-package="com.startup.failure" scoped-proxy="TARGET_CLASS" />
So this way I don't need my proxied beans to implement interfaces? (using CGLIB not JDK standard).
Didn't tested this but i think it should work.
Of course you need to have cglib library, you need it with <aop:scoped-proxy> anyway.