@ComponentScan excludeFilters 自定义过滤器
一、@ComponentScan的作用
- @ComponentScan用于类或接口上，主要是指定扫描路径并把带有指定注解的类注册到Spring容器中。
- 会被自动装配的注解包括@Component、@Bean、@Controller、@Service、@Repository等等。
二、定义组件
1. @Service注解的类
MyService类被扫描后，会生成名为myBeanService的实例
package info.pigg.study.java.service;
import org.springframework.stereotype.Service;
@Service("myBeanService")
public class MyService {
}
2. @Configuration+@Bean
MyConfig 类被扫描后，会生成名为myBeanPerson和myBeanUser两个实例
package info.pigg.study.java.config;
@Configuration
public class MyConfig {
@Bean(name = "myBeanPerson")
public Person myBeanPerson(){
return new Person("king", 31);
}
@Bean(name = "myBeanUser")
public User myBeanUser(){
return new User("king", 31);
}
}
三、在主程序类中测试
上面定义的组件都属于"info.pigg.study.java"，所以添加@ComponentScan(value = “info.pigg.study.java”)
@SpringBootApplication
@ComponentScan(value = "info.pigg.study.java")
public class DictApplication {
public static void main(String[] args) {
ConfigurableApplicationContext run = SpringApplication.run(DictApplication.class, args);
String[] names = run.getBeanDefinitionNames();
//打印出名称包含myBean的实例
for (String name : names) {
if (name.contains("myBean")) {
System.out.println(name);
}
}
}
}
测试结果如下：
myBeanService
myBeanPerson
myBeanUser
四、@ComponentScan中excludeFilters使用
在@ComponentScan可以设置includeFilters和excludeFilters，来自定义过滤器。一般excludeFilters用的比较多。
1. 过滤指定的类名
type = FilterType.ASSIGNABLE_TYPE是根据类class来过滤，后面classes指向类名
@SpringBootApplication
@ComponentScan(value = "info.pigg.study.java", excludeFilters = {
@ComponentScan.Filter(type = FilterType.ASSIGNABLE_TYPE, classes = {
MyService.class})})
public class DictApplication {
//和上面一样，省略
}
测试结果如下：
myBeanPerson
myBeanUser
2. 过滤指定的注解
在"info.pigg.study.java"包和子包下，排除有@Service注解的类
@SpringBootApplication
@ComponentScan(value = "info.pigg.study.java", excludeFilters = {
@ComponentScan.Filter(type = FilterType.ANNOTATION, classes = {
Service.class})})
public class DictApplication {
}
测试结果如下：
myBeanPerson
myBea
3. 自定义过滤
type = FilterType.CUSTOM,是自定义过滤，classes 指定的类要实现TypeFilter接口，在match方法中可以获取当前扫描到的类的信息，比如注解、类名和类路径。
@SpringBootApplication
@ComponentScan(value = "info.pigg.study.java", excludeFilters = {
@ComponentScan.Filter(type = FilterType.CUSTOM, classes = {
MyTypeFilter.class})})
public class DictApplication {
}
下面举例：在类名包含"MyService"时，match方法返回true，这样在excludeFilters时，包含"MyService"的类就会被排除掉。
package info.pigg.study.java.filter;
import org.springframework.core.io.Resource;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.core.type.ClassMetadata;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.core.type.filter.TypeFilter;
import java.io.IOException;
public class MyTypeFilter implements TypeFilter {
@Override
public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException {
//获取当前类注解的信息
AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata();
//获取当前类资源(类的路径)
Resource resource = metadataReader.getResource();
ClassMetadata classMetadata = metadataReader.getClassMetadata();
System.out.println("当前正在被扫描的类的类名" + classMetadata.getClassName());
if (classMetadata.getClassName().contains("MyService")){
return true;
}
return false;
}
}
测试结果如下：
myBeanPerson
myBea