How to exclude classes/packages from Component Scan in Spring Framework? The task is a bit tricky, especially when regexp is involved. See how it works!
Example Spring beans
Let’s say that we’ve got the following two classes in com.farenda.java.spring.excludescan package:
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package com.farenda.java.spring.excludescan;
import org.springframework.stereotype.Service;
@Service
public class ExcludedService {
public ExcludedService() {
System.out.println("Instantiating " + getClass().getSimpleName());
}
}
package com.farenda.java.spring.excludescan;
import org.springframework.stereotype.Service;
@Service
public class IncludedService {
public IncludedService() {
System.out.println("Instantiating " + getClass().getSimpleName());
}
}
We want to scan the whole package and include every component except ExcludedService. In our case included beans should contain only IncludedService.
ComponentScan exclude - using annotations
To exclude some beans we can use excludeFilters on the @ComponentScan annotation like this:
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package com.farenda.java.spring;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.*;
import org.springframework.context.annotation.ComponentScan.Filter;
import java.util.Arrays;
@ComponentScan(basePackages = "com.farenda.java.spring.excludescan",
excludeFilters =@Filter(
type = FilterType.REGEX,
pattern = "com\\.farenda\\.java\\.spring\\.excludescan\\.Excluded.*"))
@EnableAutoConfiguration
public class ExcludingFromComponentScanExample {
public static void main(String[] args) throws Exception {
ApplicationContext context =
SpringApplication.run(ExcludingFromComponentScanExample.class, args);
String[] beans = context.getBeanDefinitionNames();
// sort names only to make output more readable:
Arrays.sort(beans);
System.out.println("Defined beans: ");
for (String bean : beans) {
System.out.println(bean);
}
}
}
We apply REGEX FilterType that allows us nicely exclude single classes and whole packages. When we run the application you can see that only includedService is among beans in ApplicationContext built from ComponentScan:
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...
:: Spring Boot :: (v1.2.3.RELEASE)
2015-12-20 13:08:37.601 INFO 4077 --- [ main] .f.j.s.ExcludingFromComponentScanExample
2015-12-20 13:08:37.660 INFO 4077 --- [ main] s.c.a.AnnotationConfigApplicationContext
Instantiating IncludedService
...
2015-12-20 13:08:39.292 INFO 4077 --- [ main] .f.j.s.ExcludingFromComponentScanExample : Started ExcludingFromComponentScanExample in 2.204 seconds (JVM running for 2.841)
Defined beans:
excludingFromComponentScanExample
includedService
mbeanExporter
mbeanServer
objectNamingStrategy
org.springframework.boot.autoconfigure.AutoConfigurationPackages
org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration
org.springframework.boot.autoconfigure.condition.BeanTypeRegistry
org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration
org.springframework.context.annotation.ConfigurationClassPostProcessor.enhancedConfigurationProcessor
org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor
org.springframework.context.annotation.internalAutowiredAnnotationProcessor
org.springframework.context.annotation.internalCommonAnnotationProcessor
org.springframework.context.annotation.internalConfigurationAnnotationProcessor
org.springframework.context.annotation.internalRequiredAnnotationProcessor
propertySourcesPlaceholderConfigurer
2015-12-20 13:08:39.295 INFO 4077 --- [ Thread-1] s.c.a.AnnotationConfigApplicationContext : Closing org.springframework.context.annotation.AnnotationConfigApplicationContext@7a187f14: startup date [Sun Dec 20 13:08:37 CET 2015]; root of context hierarchy
2015-12-20 13:08:39.298 INFO 4077 --- [ Thread-1] o.s.j.e.a.AnnotationMBeanExporter : Unregistering JMX-exposed beans on shutdown
Process finished with exit code 0
The same filtering mechanism can be used with includeFilters attribute, to select classes/packages that should be included in Spring ApplicationContext.
ComponentScan exclude - XML version
If you happen to still work with XML Spring Configuration, then the same thing can be done in the following way:
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<context:component-scan
base-package="com.farenda.java.spring.excludescan">
<context:exclude-filter type="regex"
expression="com\.farenda\.java\.spring\.excludescan\.Excluded.*"/>
</context:component-scan>
Resources
- Check out Spring Framework Tutorial!