spring中@ComponentScan自动扫描并指定扫描规则
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;
// 名字默认是类名首字母小写
@Repository
public class BookDao {
}
BookService
package com.tianxia.springannotation.service;
public interface BookService {
}
BookServiceImpl
package com.tianxia.springannotation.service.impl;
import com.tianxia.springannotation.service.BookService;
import org.springframework.stereotype.Service;
@Service
public class BookServiceImpl implements BookService {
}
BookController
package com.tianxia.springannotation.controller;
import org.springframework.stereotype.Controller;
@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;
@SpringBootTest
@RunWith(SpringJUnit4ClassRunner.class)
public class ComponentScanTest {
@Test
public 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;
@SpringBootApplication
// value指定要扫描的包
@ComponentScan(value="com.tianxia.springannotation", excludeFilters={
@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;
@SpringBootApplication
// value指定要扫描的包
@ComponentScan(value="com.tianxia.springannotation", includeFilters={
@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={
@ComponentScan.Filter(type=FilterType.ANNOTATION, classes={Controller.class})
}, useDefaultFilters=false),
@ComponentScan(value="com.tianxia.springannotation", includeFilters={
@ComponentScan.Filter(type=FilterType.ANNOTATION, classes={Service.class})
}, useDefaultFilters=false)
})
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