1.使用注解配置包扫描

1.1.创建相关类

分别创建BookDao、BookService、BookServiceImpl以及BookController这三个类，并在这三个类中分别添加@Repository、@Service、@Controller注解

• BookDao

  package com.tianxia.springannotation.dao;import org.springframework.stereotype.Repository;/* BookDao* @author liqb* @date 2023-04-21 16:37/
  // 名字默认是类名首字母小写
  @Repository
  public class BookDao {
  }
  

• BookService

  package com.tianxia.springannotation.service;/* BookService* @author liqb* @date 2023-04-21 16:38/
  public interface BookService {
  }
  

• BookServiceImpl

  package com.tianxia.springannotation.service.impl;import com.tianxia.springannotation.service.BookService;
  import org.springframework.stereotype.Service;/* BookServiceImpl* @author liqb* @date 2023-04-21 16:38/
  @Service
  public class BookServiceImpl implements BookService {
  }
  

• BookController

  package com.tianxia.springannotation.controller;import org.springframework.stereotype.Controller;/* BookController* @author liqb* @date 2023-04-21 16:39/
  @Controller
  public class BookController {
  }
  

1.2.SpringBoot启动类默认就有配置@ComponentScan

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@SpringBootConfiguration
@EnableAutoConfiguration
@ComponentScan(excludeFilters = { @Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),@Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
public @interface SpringBootApplication {
}

1.3.查看IOC中的bean的名称

package com.tianxia.springannotation;import com.tianxia.springannotation.config.MainConfig;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;/* ComponentScanTest* @author liqb* @date 2023-04-21 16:45/
@SpringBootTest
@RunWith(SpringJUnit4ClassRunner.class)
public class ComponentScanTest {/* 查看IOC容器中有哪些bean* @author liqb* @date 2023-04-21 16:45*/@Testpublic void test() {AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(SpringAnnotationApplication.class);// 我们现在就来看一下IOC容器中有哪些bean，即容器中所有bean定义的名字String[] definitionNames = applicationContext.getBeanDefinitionNames();for (String name : definitionNames) {System.out.println(name);}}
}

2.扫描时排除注解标注的类

在注解类上通过@ComponentScan注解的excludeFilters()方法

package com.tianxia.springannotation;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.FilterType;
import org.springframework.stereotype.Controller;
import org.springframework.stereotype.Service;/* 启动类* @author liqb* @date 2023-04-21 16:12/
@SpringBootApplication
// value指定要扫描的包
@ComponentScan(value="com.tianxia.springannotation", excludeFilters={/ type：指定你要排除的规则，是按照注解进行排除，还是按照给定的类型进行排除，还是按照正则表达式进行排除，等等* classes：除了@Controller和@Service标注的组件之外，IOC容器中剩下的组件我都要，即相当于是我要排除@Controller和@Service这俩注解标注的组件。*/@ComponentScan.Filter(type= FilterType.ANNOTATION, classes={Controller.class, Service.class})
})
public class SpringAnnotationApplication {public static void main(String[] args) {SpringApplication.run(SpringAnnotationApplication.class, args);}
}

3.扫描时只包含注解标注的类

在注解类中的includeFilters()方法来指定Spring在进行包扫描时，只包含哪些注解标注的

这里需要注意的是，当我们使用includeFilters()方法来指定只包含哪些注解标注的类时，需要禁用掉默认的过滤规则

package com.tianxia.springannotation;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.FilterType;
import org.springframework.stereotype.Controller;/* 启动类* @author liqb* @date 2023-04-21 16:12/
@SpringBootApplication
// value指定要扫描的包
@ComponentScan(value="com.tianxia.springannotation", includeFilters={/ type：指定你要排除的规则，是按照注解进行排除，还是按照给定的类型进行排除，还是按照正则表达式进行排除，等等* classes：我们需要Spring在扫描时，只包含@Controller注解标注的类*/@ComponentScan.Filter(type=FilterType.ANNOTATION, classes={Controller.class})
}, useDefaultFilters=false)
public class SpringAnnotationApplication {public static void main(String[] args) {SpringApplication.run(SpringAnnotationApplication.class, args);}
}

4.重复注解

@ComponentScans({@ComponentScan(value="com.tianxia.springannotation", includeFilters={/ type：指定你要排除的规则，是按照注解进行排除，还是按照给定的类型进行排除，还是按照正则表达式进行排除，等等* classes：我们需要Spring在扫描时，只包含@Controller注解标注的类*/@ComponentScan.Filter(type=FilterType.ANNOTATION, classes={Controller.class})}, useDefaultFilters=false),@ComponentScan(value="com.tianxia.springannotation", includeFilters={/ type：指定你要排除的规则，是按照注解进行排除，还是按照给定的类型进行排除，还是按照正则表达式进行排除，等等* classes：我们需要Spring在扫描时，只包含@Controller注解标注的类*/@ComponentScan.Filter(type=FilterType.ANNOTATION, classes={Service.class})}, useDefaultFilters=false)
})