Spring框架bean的配置（3）：基于注解的配置

Z时代
2024-01-10
分类：综合

本文内容纲要：Spring框架bean的配置（3）：基于注解的配置

1.基于注解的配置：

@Component: 基本注解, 标识了一个受 Spring 管理的组件

@Respository: 标识持久层组件

@Service: 标识服务层(业务层)组件

@Controller: 标识表现层组件

将这些架包放入在工程目录下建立的lib文件夹里，并解压

commons-logging-1.1.1

spring-aop-4.0.0.RELEASE

spring-beans-4.0.0.RELEASE

spring-context-4.0.0.RELEASE

spring-core-4.0.0.RELEASE

spring-expression-4.0.0.RELEASE

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建立接口：UserRepository

package com.atguigu.spring.beans.annotation.test;
public interface UserRepository {
    void save();
}

建立类：UserRepositoryImpl继承于接口：UserRepository

package com.atguigu.spring.beans.annotation.test;
import org.springframework.stereotype.Repository;
@Repository("userRepository") //标识持久层组件
public class UserRepositoryImpl implements UserRepository {
    public void save() {
        System.out.println("panpan123");
    }
}

建立类：UserService

package com.atguigu.spring.beans.annotation.test;
import org.springframework.stereotype.Service;
@Service  //标识服务层(业务层)组件
public class UserService {
    public void add(){
        System.out.println("panpan456");
    }
}

建立类：UserController

package com.atguigu.spring.beans.annotation.test;
import org.springframework.stereotype.Controller;
@Controller  //标识表现层组件
public class UserController {
    public void test(){
        System.out.println("panpan789");
    }
}

上述类都是建立在包com.atguigu.spring.beans.annotation.test之下；

spring的xml配置文件：beansannotation.xml，在com.atguigu.spring.beans.annotation.test包或子包下带有上述四个注解的，可以被IOC容器识别

<context:component-scan  base-package="com.atguigu.spring.beans.annotation.test" >    
</context:component-scan>

加入resource-pattern="repository/*.class，是指识别repository注解的类；

<context:component-scan   base-package="com.atguigu.spring.beans.annotation.test"  resource-pattern="repository/*.class">    
</context:component-scan>

注解过滤：指不包含类型是注解，导入的包（import后面的）是org.springframework.stereotype.Repository的类；

<context:component-scan
base-package="com.atguigu.spring.beans.annotation"
<context:exclude-filter type="annotation" 
expression="org.springframework.stereotype.Repository"/>
</context:component-scan>

取消默认的use-default-filters="false"，包含...

<context:component-scan
base-package="com.atguigu.spring.beans.annotation" use-default-filters="false">
<context:include-filter type="annotation" 
expression="org.springframework.stereotype.Repository"/>
</context:component-scan>

类过滤：type="assignable"，不包含全类名是com.atguigu.spring.beans.annotation.test.UserRepository

<context:component-scan 
base-package="com.atguigu.spring.beans.annotation"
<context:exclude-filter type="assignable" expression="com.atguigu.spring.beans.annotation.test.UserRepository"/>
</context:component-scan>

类过滤：type="assignable"，取消默认的use-default-filters="false"，只包含全类名为com.atguigu.spring.beans.annotation.test.UserRepositoryImpl类

<context:component-scan 
base-package="com.atguigu.spring.beans.annotation" use-default-filters="false">
<context:exclude-filter type="assignable" expression="com.atguigu.spring.beans.annotation.test.UserRepositoryImpl"/>
</context:component-scan>

建立Main类，进行测试：

package com.atguigu.spring.beans.annotation.test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
public class Main {
    public static void main(String[] args) {
        ApplicationContext ctx=new ClassPathXmlApplicationContext("beansannotation.xml");
        TestObject test=(TestObject) ctx.getBean("testObject");
        System.out.println(test);
        UserController controller=(UserController) ctx.getBean("userController");
        System.out.println(controller);
        UserService service=(UserService) ctx.getBean("userService");
        System.out.println(service);
        UserRepositoryImpl repository=(UserRepositoryImpl) ctx.getBean("userRepository");
        System.out.println(repository);
    }
}