Spring 3 JavaConfig @Import example
Normally, you will split a large Spring XML bean files into multiple small files, group by module or category, to make things more maintainable and modular. For example,
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd"> <import resource="config/customer.xml"/> <import resource="config/scheduler.xml"/> </beans>
In Spring3 JavaConfig, the equivalent functionality is @Import.
package com.mkyong.config; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.Import; @Configuration @Import({ CustomerConfig.class, SchedulerConfig.class }) public class AppConfig { }
@Import Example
See a full example of using JavaConfig @Import.
1. Directory Structure
Directory structure of this example.

2. Spring Beans
Two simple Spring beans.
File : CustomerBo.java
package com.mkyong.core; public class CustomerBo { public void printMsg(String msg) { System.out.println("CustomerBo : " + msg); } }
File : SchedulerBo.java
package com.mkyong.core; public class SchedulerBo { public void printMsg(String msg) { System.out.println("SchedulerBo : " + msg); } }
3. @Configuration example
Now, use JavaConfig @Configuration to declare above beans.
File : CustomerConfig.java
package com.mkyong.config; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import com.mkyong.core.CustomerBo; @Configuration public class CustomerConfig { @Bean(name="customer") public CustomerBo customerBo(){ return new CustomerBo(); } }
File : SchedulerConfig.java
package com.mkyong.config; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; import com.mkyong.core.SchedulerBo; @Configuration public class SchedulerConfig { @Bean(name="scheduler") public SchedulerBo suchedulerBo(){ return new SchedulerBo(); } }
4. @Import example
Use @Import to load multiple configuration files.
File : AppConfig.java
package com.mkyong.config; import org.springframework.context.annotation.Configuration; import org.springframework.context.annotation.Import; @Configuration @Import({ CustomerConfig.class, SchedulerConfig.class }) public class AppConfig { }
5. Run it
Load the main configuration file , and test it.
package com.mkyong.core; import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.AnnotationConfigApplicationContext; import com.mkyong.config.AppConfig; public class App { public static void main(String[] args) { ApplicationContext context = new AnnotationConfigApplicationContext( AppConfig.class); CustomerBo customer = (CustomerBo) context.getBean("customer"); customer.printMsg("Hello 1"); SchedulerBo scheduler = (SchedulerBo) context.getBean("scheduler"); scheduler.printMsg("Hello 2"); } }
Output
CustomerBo : Hello 1 SchedulerBo : Hello 2
Download Source Code
Download It – Spring3-JavaConfig-Import-Example.zip (7 KB)
References
Tags : javaconfig spring3

Thanks!
It seems we can also extend the classes annotated with @Configuration.
I tried something like
@Configuration
public class ParentConfig{
@Bean(name=”a”)
public A getA(){…}
}
@Configuration
public class ChildConfig extends ParentConfig{
@Bean(name =”b”)
public B getB(){….}
}
ApplicationContext ctx = new AnnotationConfigApplicationContext(ChildConfig.class);
ctx.getBean(“a”) returns object of type “A”
So more or less some thing like include vs import
So define 1 file AppConfig.java which will configure every needed bean instead of bean_nameConfig.java for each bean ( 1 main config file instead many )
OR
each needed class as bean will have his configFile like in the example above?
OR
Instead of beanNameConfig.java , there is another way to declare a class as a bean , @Component , If i’m not wrong , (and another ways ? @Service ? ) , is it Spring 2.5 way? no needed for Spring 3 way?
Better practice is group related beans in in a single module file, then create a main config file to include all, centralize control.
It will make your project more modular and easy to maintain.
Of course, @Component is still supported in Spring3 :). JavaConfig is just a new way to define the configuration stuff in Spring3.