Scan Spring's component classes by annotating @ComponentScan on the class.

Optional parameters for @ComponentScan

• basePackages: Specifies the root package directory that needs to be scanned, and its subdirectories will also be scanned. The default path is the @ComponentScan annotation class directory and its subdirectories
• Alias for value:basePackages
• basePackageClasses: Specifies the root class directory that needs to be scanned, and its subdirectories will also be scanned
• lazyInit: lazy to load, default false
• useDefaultFilters: Whether the auto-scan component is enabled, default true; false means that only the filter rules specified below are applied
• excludeFilters: Specify component types that do not require scanning (see @Filter configuration for details)
• IncudeFilters: Specify the type of component to scan (see @Filter configuration for details)
• scopedProxy: Proxy mode ScopedProxyMode
  • DEFAULT: Default, usually NO
  • NO: No need to create proxy
  • INTERFACES: Create JDK Proxy
  • TARGET_CLASS: Create proxy using CGLIB
• nameGenerator: Specifies the class that implements the interface BeanNameGenerator, which can be used to define the generation rules for BeanName
• scopeResolver: Specifies the class that implements the interface AnnotationScopeMetadataResolver, configures the scope, and proxy mode scopedProxy
• resourcePattern: Used to match the appropriate components, default is **/*.class, includeFilters and excludeFilters are recommended

Methods for configuring multiple @ComponentScan s

All three of the following are possible

@ComponentScans(
    @ComponentScan({"com.xxx.aaa","com.xxx.bbb"})
)
@Configuration
public class Config {}

@ComponentScan({"com.xxx.aaa","com.xxx.bbb"})
@Configuration
public class Config {}

@ComponentScan({"com.xxx.aaa"})
@ComponentScan({"com.xxx.bbb"})
@Configuration
public class Config {}

Configure Filter@Filter

1. Filter @Service annotation classes

@Configuration
@ComponentScan(
    excludeFilters = {
        @Filter(type = FilterType.ANNOTATION, classes = Service.class)
    }
)
public class Config {}

2. Filter Dog Classes

@Configuration
@ComponentScan(
    excludeFilters = {
        @Filter(type = FilterType.ASSIGNABLE_TYPE, classes = Dog.class)
    }
)
public class Config {}

3. Regular Matching, Filtering Classes Suffixed with a

@Configuration
@ComponentScan(
    excludeFilters = {
        @Filter(type = FilterType.REGEX, pattern = {"..*a"})
    }
)
public class Config {}

4. Customize the filter rule class to filter the class containing a

@Configuration
@ComponentScan(
    excludeFilters = {
        @Filter(type = FilterType.CUSTOM, classes = MyFilterType.class)
    }
)
public class Config {}
// Implement TypeFilter custom rule: filter BeanName containing a
public class MyFilterType implements TypeFilter Custom Rules {
  @Override
  public boolean match(MetadataReader reader, MetadataReaderFactory factory) throws IOException {
    return reader.getClassMetadata().getClassName().contains("a");
  }
}

An example

Config class is configured with the following rules:

1. The package paths com.xxx.aaa, com.xxx.bbb need to be scanned
2. Exclude the @Service annotation class and the Dog class under the com.xxx.aaa path
3. com.xxx.bbb does not enable automatic scanning, but requires the Cat class to be included

@ComponentScan(
    value = {"com.xxx.aaa"},
    excludeFilters = {
        @Filter(type = FilterType.ANNOTATION, classes = Service.class),
        @Filter(type = FilterType.ASSIGNABLE_TYPE, classes = Dog.class)
    }
)
@ComponentScan(
    value = {"com.xxx.bbb"},
    useDefaultFilters = false,
    includeFilters = {
        @Filter(type = FilterType.ASSIGNABLE_TYPE, classes = Cat.class)
    }
)
@Configuration
public class Config {
}