Spring Filter components in auto scanning

最新推荐文章于 2025-11-23 13:27:25 发布

转载最新推荐文章于 2025-11-23 13:27:25 发布 · 86 阅读

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原文链接：http://www.cnblogs.com/ghgyj/p/4749814.html

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#java

本文将指导您如何在Spring中实现组件自动扫描，并展示如何使用过滤器来筛选匹配特定规则的组件，包括如何包含或排除指定的组件。

In this Spring auto component scanning tutorial, you learn about how to make Spring auto scan your components. In this article, we show you how to do component filter in auto scanning process.

1. Filter component – include

See following example to use Spring “filtering” to scan and register components’ name which matched defined “regex”, even the class is not annotated with @Component.

DAO layer

package com.mkyong.customer.dao;

public class CustomerDAO 
{
    @Override
    public String toString() {
        return "Hello , This is CustomerDAO";
    }   
}

Service layer

package com.mkyong.customer.services;

import org.springframework.beans.factory.annotation.Autowired;
import com.mkyong.customer.dao.CustomerDAO;

public class CustomerService 
{
    @Autowired
    CustomerDAO customerDAO;

    @Override
    public String toString() {
        return "CustomerService [customerDAO=" + customerDAO + "]";
    }
        
}

Spring filtering.

<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.mkyong" >

        <context:include-filter type="regex" 
                       expression="com.mkyong.customer.dao.*DAO.*" />

        <context:include-filter type="regex" 
                       expression="com.mkyong.customer.services.*Service.*" />

    </context:component-scan>

</beans>

Run it

package com.mkyong.common;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.mkyong.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);
        
    }
}

Output

CustomerService [customerDAO=Hello , This is CustomerDAO]

In this XML filtering, all files’s name contains DAO or Service (*DAO.*, *Services.*) word will be detect and register in Spring container.

2. Filter component – exclude

On the other hand, you can also exclude specified components, to avoid Spring to detect and register it in Spring container.

Exclude those files annotated with @Service.

    <context:component-scan base-package="com.mkyong.customer" >
        <context:exclude-filter type="annotation" 
            expression="org.springframework.stereotype.Service" />      
    </context:component-scan>

Exclude those files name contains DAO word.

    <context:component-scan base-package="com.mkyong" >
        <context:exclude-filter type="regex" 
            expression="com.mkyong.customer.dao.*DAO.*" />      
    </context:component-scan>

转载于:https://www.cnblogs.com/ghgyj/p/4749814.html