基于注解的方式配置bean（基于注解配置Bean，基于注解来装配Bean的属性）
在classpath中扫描组件
组件扫描（component scanning）：Spring能够从classpath下自动扫描，侦测和实例化具有特定注解的组件。
特定组件包括：
-@Component：基本注解，表示了一个受Spring管理的组件
-@Respository:标识持久层组件
-@Service：标识服务层组（业务层）件
-@Controller:标识表现层组件
对于扫描到的组件，Spring有默认的命名策略：使用非限定类名，第一个字母小写，也可以在注解中通过value属性值标识组件的名称。
当在组件类上使用了特定的注解之后，还需要在Spring的配置文件中声明<context:component-scan>:
-base-package属性指定一个需要扫描的基类包，Spring容器将会扫描这个基类包里面及其子包中的所有类。
-当需要扫描多个包时，可以使用逗号分隔。
-如果仅希望扫描特定的类而不非基包下的所有类，可以使用resource-pattern属性过滤特定的类，示例：
<context:component-scan base-package="com.logan.spring.beans" resource-pattern="autowire/*.class"/>
-<context:include-filter>子节点表示要包含的目标类
-<context:exclude-filter>子节点表示要排除在外的目标
-<context:component-scan>下可以拥有若干个<context:include-filter>和<context:exclude-filter>子节点。
看代码
package logan.spring.study.annotation; import org.springframework.stereotype.Component; @Component public class TestObject { }
package logan.spring.study.annotation.repository; import org.springframework.stereotype.Repository; @Repository("userRepository") public class UserRepositoryImpl implements UserRepository { @Override public void save() { // TODO Auto-generated method stub System.out.println("UserRepository Save..."); } }
package logan.spring.study.annotation.service; import org.springframework.stereotype.Service; @Service public class UserService { public void add(){ System.out.println("UserService add..."); } }
package logan.spring.study.annotation.controller; import org.springframework.stereotype.Controller; @Controller public class UserController { public void execute(){ System.out.println("UserController execute..."); } }
配置文件
<?xml version="1.0" encoding="UTF-8"?> <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.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd"> <context:component-scan base-package="logan.spring.study.annotation"></context:component-scan> </beans>
package logan.spring.study.annotation; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import logan.spring.study.annotation.controller.UserController; import logan.spring.study.annotation.repository.UserRepository; import logan.spring.study.annotation.service.UserService; public class Main { public static void main(String[] args) { System.out.println(1); ApplicationContext ctx = new ClassPathXmlApplicationContext("beans-annotation.xml"); System.out.println(2); TestObject to = (TestObject) ctx.getBean("testObject"); System.out.println(to); UserController userController = (UserController) ctx.getBean("userController"); System.out.println(userController); UserService userService = (UserService) ctx.getBean("userService"); System.out.println(userService); UserRepository userRepository = (UserRepository) ctx.getBean("userRepository"); System.out.println(userRepository); } }
package logan.spring.study.annotation.repository; public interface UserRepository { void save(); }
返回的结果为
五月 24, 2017 10:25:12 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@42110406: startup date [Wed May 24 22:25:11 CST 2017]; root of context hierarchy 五月 24, 2017 10:25:12 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 信息: Loading XML bean definitions from class path resource [beans-annotation.xml] logan.spring.study.annotation.TestObject@78ac1102 logan.spring.study.annotation.controller.UserController@2de8284b logan.spring.study.annotation.service.UserService@396e2f39 logan.spring.study.annotation.repository.UserRepositoryImpl@a74868d
这里使用的jar包有：
可以如下改规则：（通过resource-pattern指定扫描资源）
<?xml version="1.0" encoding="UTF-8"?> <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.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd"> <context:component-scan base-package="logan.spring.study.annotation" resource-pattern="repository/*.class" ></context:component-scan> </beans>
package logan.spring.study.annotation; import org.springframework.context.ApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import logan.spring.study.annotation.controller.UserController; import logan.spring.study.annotation.repository.UserRepository; import logan.spring.study.annotation.service.UserService; public class Main { public static void main(String[] args) { ApplicationContext ctx = new ClassPathXmlApplicationContext("beans-annotation.xml"); // TestObject to = (TestObject) ctx.getBean("testObject"); // System.out.println(to); // UserController userController = (UserController) ctx.getBean("userController"); // System.out.println(userController); // UserService userService = (UserService) ctx.getBean("userService"); // System.out.println(userService); UserRepository userRepository = (UserRepository) ctx.getBean("userRepository"); System.out.println(userRepository); } }
输出的结果为：
五月 24, 2017 10:30:25 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh 信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@42110406: startup date [Wed May 24 22:30:25 CST 2017]; root of context hierarchy 五月 24, 2017 10:30:25 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions 信息: Loading XML bean definitions from class path resource [beans-annotation.xml] logan.spring.study.annotation.repository.UserRepositoryImpl@32eebfca
<context:include-filter>和<context:exclude-filter>子节点支持多种类型的过滤表达式：
| 类别 | 示例 | 说明 |
| annotation | ||
| assinable | ||
| aspecct | ||
| regex | ||
| custom |
原文：http://www.cnblogs.com/LoganChen/p/6886183.html