Spring入门第十四课
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 | com.logan.XxxAnnotation | 所有标注了XxxAnnotation的类,该类型采用目标类是否标注了某个注解进行过滤 |
| assinable | com.logan.XxxService | 所有继承或扩展XxxService的类,该类型采用目标类是否基层或扩展某个特定类型进行过滤 |
| aspecct | com.logan.*Service+ | 所有类名以Service结束的类以及继承或者扩展它们的类,该类型采用AspectJ表达式进行过滤。 |
| regex | com.logan.\anno\.* | 所有com.logan.anno包下的类,该类型采用正则表达式根据类的类名进行过滤 |
| custom | 采用XxxTypeFilter,通过代码的方式定义过滤规则,该类必须实现org.springframework.core.type.TypeFilter接口。 |
看如下配置:
<?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:exclude-filter type="annotation" expression="org.springframework.stereotype.Repository"></context:exclude-filter></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);
} }
下面是输出结果
五月 25, 2017 10:21:53 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@42110406: startup date [Thu May 25 22:21:53 CST 2017]; root of context hierarchy
五月 25, 2017 10:21:53 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@75881071
logan.spring.study.annotation.controller.UserController@2a70a3d8
logan.spring.study.annotation.service.UserService@289d1c02
看如下代码:
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);
}
}
<?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" use-default-filters="false">
<context:include-filter type="annotation" expression="org.springframework.stereotype.Repository"></context:include-filter></context:component-scan> </beans>
输出结果
五月 26, 2017 9:37:08 下午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@42110406: startup date [Fri May 26 21:37:08 CST 2017]; root of context hierarchy
五月 26, 2017 9:37:08 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@78ac1102
<context:include-filter>子节点包含哪些表达式的组件,该子节点需要use-default-filter配合使用。
看如下配置:(指定不包括谁)
<?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:exclude-filter type="assignable" expression="logan.spring.study.annotation.repository.UserRepository"></context:exclude-filter>
</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);
}
}
输出结果:
五月 27, 2017 11:04:35 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@42110406: startup date [Sat May 27 11:04:35 CST 2017]; root of context hierarchy
五月 27, 2017 11:04:36 上午 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@289d1c02
logan.spring.study.annotation.controller.UserController@22eeefeb
logan.spring.study.annotation.service.UserService@17d0685f
Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'userRepository' available
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:687)
at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1207)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:284)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1081)
at logan.spring.study.annotation.Main.main(Main.java:22)
看下面配置:(指定包含谁)
<?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" use-default-filters="false">
<context:include-filter type="assignable" expression="logan.spring.study.annotation.repository.UserRepository"></context:include-filter>
</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);
}
}
输出结果:
五月 27, 2017 11:07:17 上午 org.springframework.context.support.ClassPathXmlApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@42110406: startup date [Sat May 27 11:07:17 CST 2017]; root of context hierarchy
五月 27, 2017 11:07:17 上午 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@13eb8acf
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