在这个Spring自动组件扫描的教程,您已经了解如何使Spring自动扫描您的组件。在这篇文章中,我们将展示如何使用组件过滤器自动扫描过程。
1.过滤组件 - 包含
参见下面的例子中使用Spring “过滤” 扫描并注册匹配定义“regex”,即使该类组件的名称未标注 @Component 。
DAO 层
package com.yiibai.customer.dao; public class CustomerDAO { @Override public String toString() { return "Hello , This is CustomerDAO"; } }
Service 层
package com.yiibai.customer.services; import org.springframework.beans.factory.annotation.Autowired; import com.yiibai.customer.dao.CustomerDAO; public class CustomerService { @Autowired CustomerDAO customerDAO; @Override public String toString() { return "CustomerService [customerDAO=" + customerDAO + "]"; } }
Spring 过滤
<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-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"> <context:component-scan base-package="com.yiibai" > <context:include-filter type="regex" expression="com.yiibai.customer.dao.*DAO.*" /> <context:include-filter type="regex" expression="com.yiibai.customer.services.*Service.*" /> </context:component-scan> </beans>
执行
package com.yiibai.common; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import com.yiibai.customer.services.CustomerService; public class App { public static void main( String[] args ) { ApplicationContext context = new ClassPathXmlApplicationContext(new String[] {"Spring-AutoScan.xml"}); CustomerService cust = (CustomerService)context.getBean("customerService"); System.out.println(cust); } }
输出
CustomerService [customerDAO=Hello , This is CustomerDAO]
在这个XML过滤中,所有文件的名称中包含 DAO 或 Service(*DAO.*, *Services.*) 单词将被检测并在 Spring 容器中注册。
2.过滤组件 - 不包含
另外,您还可以排除指定组件,以避免 Spring 检测和 Spring 容器注册。不包括在这些文件中标注有 @Service 。
<context:component-scan base-package="com.yiibai.customer" > <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Service" /> </context:component-scan>
不包括那些包含DAO这个词组文件名。
<context:component-scan base-package="com.yiibai" > <context:exclude-filter type="regex" expression="com.yiibai.customer.dao.*DAO.*" /> </context:component-scan>