How do <context:include-filter> and <context:exclude-filter> work in Spring?

Question

I have several services:

• example.MailService
• example.LDAPService
• example.SQLService
• example.WebService
• example.ExcelService

annotated with @Service annotation. How can I exclude all services except one?

For example I want to use only MailService. I use the following configuration:

<context:component-scan base-package="example">     <context:include-filter type="aspectj" expression="example..MailService*" />     <context:exclude-filter type="aspectj" expression="example..*Service*" /> </context:component-scan> 

but now all services are excluded.

Why all services are excluded if exists one rule to include MailService?

Answer 1

Another way to perform this registration is with a single inclusion filter.

<context:component-scan base-package="example" use-default-filters="false">     <context:include-filter type="aspectj" expression="example..MailService*" /> </context:component-scan> 

The "use-default-filters" attribute must be set to "false" in this case to keep Spring from adding a default filter equivalent to

<context:include-filter type="annotation"                          expression="org.springframework.stereotype.Component"/> 

Answer 2

Include filters are applied after exclude filters, so you have to combine both expressions into one exclude filter. AspectJ expressions allow it (& is replaced by & due to XML syntax):

<context:exclude-filter type="aspectj"      expression="example..*Service* &amp;&amp; !example..MailService*" /> 

This is a regex, so your expression ".*Service" means 'any number of any character followed by "Service"'. This explicitly excludes the MailService you want to include.