Spring Bean XML Declaration From Different JAR - java

Suppose I'm trying to declare a bean in my dispatcher-servlet.xml:
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context.xsd">
...
<bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix">
<value>/WEB-INF/views/</value>
</property>
<property name="suffix">
<value>.jsp</value>
</property>
</bean>
...
</beans>
But here's the problem: in my own project, I've got a package named exactly org.springframework.web.servlet.view and in that package, I don't have the same classes as Spring does. What this does is it "confuses" Spring and as such, looks for the class in my project but I want it to fetch the class from the Spring libraries/jars. This results in an error along the lines of that it can't find the class. How can I tell Spring to look at its own classes and not mine?
I can't tell you how odd this is, but in my project, even my IDE can't tell where the class definition is. But in another project, I've tried yet it still works.

If you don't have any classes that share a name, there shouldn't be any issues with having the same package name. I personally recommend that you change your package name because that will help you identify the problem. If your IDE can't find the Spring classes then the Spring jar that you need probably isn't on the classpath.
There are some useful takeaways on package and class collisions here that I used to form my answer.

Can't really help you without knowing more about your environment. Your IDE may load packages in a different order than say Tomcat or just the standard JVM. Your projects manifest file may contain some clues. Here's some info on how java loads jar files and packages. Java: how classes are found
Bottom line is..
You shouldn't have a package with the name org.springframework.web.servlet.view in your project.
Java Package naming standards

Related

Conditionally load a bean in spring boot using xml configuration?

I am using Spring Boot 2.1.
I have some mixed configuration in my project : XML files and java classes with annotations.
We have this current configuration which works :
application.properties :
spring.profiles.active=dev, component1, component2
applicationContext-file.xml :
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd"
profile="component1">
<beans>
<bean id="myserviceimpl"
class="org.blabla.MyServiceImpl">
<property name="mydao">
<ref bean="mydao"></ref>
</property>
</bean>
</beans>
</beans>
We want to extract the component values from the spring.profiles.active property since they have nothing to do with the environment :
application.properties :
spring.profiles.active=dev
component1=true
component2=true
How can i condition the instantiation of the myserviceimpl bean inside the applicationContext-file.xml ?
I can no longer rely on the profile attribute since the spring.profiles.active property no longer includes
the values of the components.
Thanks for helping.
I haven't tried it by myself but I suggest to check the following:
Step 1
Create one XML file per profile (say, dev and prod for the sake of example):
app-config-dev.xml:
------------------
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd"
profile="dev">
<beans>
<!-- here define only beans that you want to load in __dev__ environment -->
<bean id="myserviceimpl"
class="org.blabla.MyServiceImpl">
<property name="mydao">
<ref bean="mydao"></ref>
</property>
</bean>
</beans>
</beans>
app-config-prod.xml:
------------------
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans.xsd"
profile="prod">
<beans>
<!-- here define only beans that you want to load in __production__ environment -->
<bean id="myserviceimpl"
class="org.blabla.MyServiceProdImpl">
<property name="mydao">
<ref bean="mydao"></ref>
</property>
</bean>
</beans>
</beans>
Step 2
Now in your "primary" applicationContext-file.xml instead of defining beans directly, include all the xml files that you've created during the step 1:
<import resource="classpath:app-config-dev.xml" />
<import resource="classpath:app-config-prod.xml" />
Read this thread for more details on this step if needed
Step 3
Remove the component1=true and component2=true from aplication properties, you don't need it anymore, the profile itself defines which beans should be loaded.
Update 1
Based OP's first comment:
You probably can try another option but I consider it a "low-level" solution and it requires deep understanding of how does spring loading process work under the hood.
So when spring starts it finds the definitions of beans (in xml, java config, annotations like #Component and so forth) and creates out of all this information a BeanDefinition - a metadata object that aggregates all the information about the bean (for example whether its singleton or prototype). At this point no beans are not created yet. Lets call this point in time a "Bean Definitions Done" point" (for the sake of explanations, its my term out of my head...
Then spring starts to build a graph of dependencies and starts creating beans, initializing them (Autowiring, post-construct methods, and so on) and placing them onto application context (if they're singletons).
Now, in spring there is an option to provide a hook called BeanFactoryPostProcessor that is invoked exactly at the "Bean Definitions Done" point. This is basically a java code that implements some interface and by itself is a spring bean that spring treats in a special way.
So you can implement this interface and manipulate the results of Bean factory.
Namely you can access every bean definition that spring has opened and if you think that the bean of this definition should not be created (here comes your custom logic that would check properties, whatever) - remove the bean definition from the registry:
For technical method of removing bean definitions see this thread
Here is an example of Bean Factory Post processor that actually adds a new bean although it wasn't registered

Spring - Beans into classes from another project

Previously I had only one project named "projectA".
I have a XML bean configuration file "service.xml" in "projectA" with bean of class "com.home.karoom.impl.adapter"
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-2.5.xsd">
<bean id="<bean id="espAdapter" class="com.home.karoom.impl.adapter">
<property name="writer" ref="writer" />
</bean>
</beans>
Now, I created new project called "projectB" and moved the bean-class "com.home.karoom.impl.adapter" to "projectB".
Now, the bean-class "com.home.karoom.impl.adapter" doesn't exist anymore in "projectA"
How ca I refer to the new class location in "projectB" using "service.xml" ?
I think you have to import the file into your project
<import resource="classpath:spring-config.xml" />
here is a good explanation on how to share code/class between projects.
Short answer is, your class com.home.karoom.impl.adapter should be put in separate project and package as a jar. Then added as dependency to your projects (A and B).
Be sure to follow convention and name your classes starting with capital letter

Error loading messages from .properties file

I'm trying to have my project's Strings/ messages stored in an external .properties file. I think I have everything wired up OK, but still I get:
org.springframework.context.NoSuchMessageException: No message found under code 'subtype.user.client' for locale 'null'.
Whenever I try:
String string = messageSource.getMessage("subtype.user.client", null, null);
My spring xml config files are as follows. Since the project is really big with lots of beans, I have different spring xml config files defining different types of beans, and a main spring.config.xml file that wires them all together.
Messages file named messages.subtypes
subtype.user.user=User
subtype.user.client=Client props
subtype.user.staff=Staff
subtype.user.clerk=Clerk
subtype.user.secretary=Secretary
Messages beans file called spring.messages.config.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
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/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">
<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basename">
<list>
<value>messages.subtypes</value>
</list>
</property>
</bean>
<bean id="myProjectLangs" class="myprojectbase.MyProjectLangs">
<property name="messageSource" ref="messageSource"></property>
</bean>
</beans>
The main spring.config.xml config file that wires all the beans together via <import resource="classpath:filename.xml"/>
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
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/aop
http://www.springframework.org/schema/aop/spring-aop-3.0.xsd ">
<aop:aspectj-autoproxy />
<import resource="classpath:spring.messages.config.xml"/>
<bean id="messageSource" class="org.springframework.context.support.ReloadableResourceBundleMessageSource" />
<context:annotation-config />
<context:component-scan base-package="myprojectbase"/>
</beans>
You get this error because you pass the Locale parameter as null. Try
String string = messageSource.getMessage("subtype.user.client", null, Locale.ENGLISH);
Even though you have not defined a file messages.subtypes_en.properties defined it should fall back to messages.subtypes.properties
A couple of things come to mind looking at your code any of which might cause the problem:
Your xml config name contains "." as separators. This is against conventions. Consider renaming your config file to spring-messages-config.xml
Your language properties file has no properties suffix, again convention suggests to name this file messages-subtypes.properties
In both your application context xml files you define a bean named messageSource. Consider deleting one of them.
My prime suspicion as to why your code does not work lies with the way you define basename on ReloadableResourceBundleMessageSource. Looking at the JavaDoc for setBasename method there is some form of convention of configuration at work:
Set a single basename, following the basic ResourceBundle convention of not specifying file extension or language codes, but in contrast to {#link ResourceBundleMessageSource} referring to a Spring resource location: e.g. "WEB-INF/messages" for "WEB-INF/messages.properties", "WEB-INF/messages_en.properties", etc. XML properties files are also supported: .g. "WEB-INF/messages" will find and load "WEB-INF/messages.xml", "WEB-INF/messages_en.xml", etc as well.
This suggests that once you have renamed your message properties file to messages-subtypes.properties, you should change your config to <value>classpath:messages-subtypes</value>, make sure that the file is in the classpath and everything should start working.
Try renaming the messages.subtypes file to messages.subtypes.properties.

Spring Framework Unable to Resolve References in IntelliJ

I set up a application configuration file for spring, added it to the facets, and set it up according to another configuration file that works perfectly.
All of the references to the spring components are visible and seem to work, but all references to items within the xml file fail to be found.
An example is with the tasks:
<task:scheduler id="taskScheduler" />
<task:executor id="taskExecutor" pool-size="1" />
<task:annotation-driven executor="taskExecutor" scheduler="taskScheduler" />
Both taskScheduler and taskExecutor cannot be resolved. As a result, the task bean never gets set up so all of my #Scheduled annotations never work.
Setting up the factory provider for services works just fine (all #Service and #Autowired annotations work), so I am completely certain the issue is with some configuration issue in the project.
What else needs to be configured in IntelliJ for the beans to work? Why does spring not rescan the file to find references to beans?
Here is where all of the springframework beans are referenced:
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:task="http://www.springframework.org/schema/task"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:cache="http://www.springframework.org/schema/cache"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.1.xsd
http://www.springframework.org/schema/task
http://www.springframework.org/schema/task/spring-task-3.1.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.1.xsd
http://www.springframework.org/schema/cache
http://www.springframework.org/schema/cache/spring-cache.xsd"
default-lazy-init="true">
The issue is having multiple contexts for application configuration files. To fix it, go to the configuration file in IntelliJ, then there is a section at the top where you can select which application context you want to put the context file into (Reads something like "Spring Application Context in module [your module]. File is included in [n] contexts"). Try selecting each one until the references resolve; it will remove it from the other contexts. My particular issue was that it was in the MVC context and it needed to be in the Spring Application Context.

Spring expression in xml configuration file

It is useful to have different property sets for different users.
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<context:property-placeholder
location="classpath:/path/to/package/default.properties,
classpath:/path/to/package/#{ systemProperties['user.name'] }.properties"/>
</beans>
When executing the application, spring does not recognize the expression. The context does not start and spring says: class path resource [path/to/package/#{ systemProperties['user.name'] }.properties] cannot be opened
When I replace the expression manually with a string resulting in a valid resource then the behaviour is as expected. The manual states it should work.
The spring-context and spring-core (3.1.2-RELEASE) are in classpath.
How come spring does not pick up the environment variable?
I'm open to alternate solutions solving the same functional problem.
SpEL expressions are not allowed there; you can do what you want indirectly, though...
<context:property-placeholder properties-ref="props"/>
<util:properties id="props" location="classpath:#{systemProperties['foo']}"/>
Here is the complete answer to the question. Keeping the override of user properties over default properties. My edit of the accepted answer got rejected.
<context:property-placeholder properties-ref="springContextCongifurationProperties"
location="classpath:/path/to/package/default.properties"
local-override="true"/>
<util:properties id="springContextCongifurationProperties"
location="classpath:/path/to/package/#{ systemProperties['user.name'] }.properties"/>

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