SpringBoot超详细讲解@Enable*注解和@Import

package com.you.boot;
import com.you.config.EnableUser;
import com.you.config.UserConfig;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Import;
@SpringBootApplication
public class BootEnable02Application {
    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(BootEnable02Application.class, args);
//      获取Bean
        Object user = context.getBean("user");
        System.out.println(user);
    }
}

package com.you.domain;
public class User {
}

package com.you.config;
import com.you.domain.User;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class UserConfig {
    @Bean
    public User user()
    {
        return new User();
    }
}

<dependency>
         <groupId>com.you</groupId>
         <artifactId>boot-enable-other</artifactId>
         <version>0.0.1-SNAPSHOT</version>
</dependency>

package com.you.config;
import org.springframework.context.annotation.Import;
import java.lang.annotation.*;
@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(UserConfig.class)
public @interface EnableUser {
}

@SpringBootApplication
@Import(User.class)
public class BootEnable02Application {
    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(BootEnable02Application.class, args);
        User user = context.getBean(User.class);
        System.out.println(user);
    }
}

package com.you.config;
import org.springframework.context.annotation.ImportSelector;
import org.springframework.core.type.AnnotationMetadata;
public class MySelector implements ImportSelector {
    @Override
    public String[] selectImports(AnnotationMetadata importinGClaSSMetadata) {
        return new String[]{"com.you.domain.User"};
    }
}

package com.you.config;
import com.you.domain.User;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanNameGenerator;
import org.springframework.context.annotation.ImportBeanDefinitionRegistrar;
import org.springframework.core.type.AnnotationMetadata;
public class MyImportBeanDefinitionRegistrar implements ImportBeanDefinitionRegistrar {
    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata, BeanDefinitionRegistry registry, BeanNameGenerator importBeanNameGenerator) {
        AbstractBeanDefinition beanDefinition = BeanDefinitionBuilder.rootBeanDefinition(User.class).getBeanDefinition();
        registry.registerBeanDefinition("user",beanDefinition);
    }
}