Spring 自动扫描组件

来源：互联网发布：妩媚的女生知乎编辑：程序博客网时间：2024/05/05 22:05

一般情况下，我们会在xml文件定义bean和component，spring有了自动扫描可以不用再xml文件中写bean和component。

下面，我通过一个简单实例来演示。

用xml文件的方法：

CustomerDao.java

package com.lzyer.springel.dao;import org.springframework.stereotype.Component;public class CustomerDao {@Overridepublic String toString() {return "This is Customer Dao";}}

CustomerService.java

package com.lzyer.springel.service;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Component;import com.lzyer.springel.dao.CustomerDao;public class CustomerService {private CustomerDao customerDao;public CustomerDao getCustomerDao() {return customerDao;}public void setCustomerDao(CustomerDao customerDao) {this.customerDao = customerDao;}@Overridepublic String toString() {return "CustomerService [customerDao=" + customerDao + "]";}}

bean.xml

<beans xmlns="http://www.springframework.org/schema/beans"    xmlns:context="http://www.springframework.org/schema/context"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-3.0.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-3.0.xsd"><bean id="customerDao" class="com.lzyer.springel.dao.CustomerDao"></bean><bean id="customerService" class="com.lzyer.springel.service.CustomerService"><property name="customerDao" ref="customerDao"></property></bean></beans>

使用注解自动扫描的方式：

CustomerDao.java

package com.lzyer.springel.dao;import org.springframework.stereotype.Component;@Componentpublic class CustomerDao {@Overridepublic String toString() {return "This is Customer Dao";}}

CustomerService.java

package com.lzyer.springel.service;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Component;import com.lzyer.springel.dao.CustomerDao;@Componentpublic class CustomerService {@Autowiredprivate CustomerDao customerDao;public CustomerDao getCustomerDao() {return customerDao;}public void setCustomerDao(CustomerDao customerDao) {this.customerDao = customerDao;}@Overridepublic String toString() {return "CustomerService [customerDao=" + customerDao + "]";}}

bean.xml

<beans xmlns="http://www.springframework.org/schema/beans"    xmlns:context="http://www.springframework.org/schema/context"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-3.0.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-3.0.xsd"><context:component-scan base-package="com.lzyer.springel"></context:component-scan><!--  <bean id="customerDao" class="com.lzyer.springel.dao.CustomerDao"></bean><bean id="customerService" class="com.lzyer.springel.service.CustomerService"><property name="customerDao" ref="customerDao"></property></bean>--></beans>

测试类：

package com.lzyer.springel;import org.springframework.context.ApplicationContext;import org.springframework.context.support.ClassPathXmlApplicationContext;import com.lzyer.springel.service.CustomerService;public class ServiceAndDaoTest {public static void main(String[] args) {ApplicationContext context = new ClassPathXmlApplicationContext(new String[]{"bean.xml"});CustomerService cs = (CustomerService)context.getBean("customerService");System.out.println(cs);}}

结果：

参考资料：http://www.mkyong.com/spring/spring-auto-scanning-components/

0 0