@Import、@ImportSource、@PropertySource、

spring導入bean的方式有三種：
Annotation-based configuration:
Java-based configuration:
XML-based configuration:

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annotation	functional
@Import	導入java配置
@ImportSource	導入xml配置
@PropertySource(value={“classpath:xxx.properties”})	導入配置變量

org.springframework.context.annotation.Import

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface Import {
	Class<?>[] value();
}

@Import的用法主要包括：
1、直接填 class數組 / 單個class
2、ImportSelector方式
3、ImportBeanDefinitionRegistrar方式

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1、直接填 class數組 / 單個class

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import({ZipkinServerConfiguration.class, BraveConfiguration.class, ZipkinQueryApiV1.class, ZipkinHttpCollector.class})
public @interface EnableZipkinServer {

}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@Import(EnableDiscoveryClientImportSelector.class)
public @interface EnableDiscoveryClient {
	/**
	 * If true, the ServiceRegistry will automatically register the local server.
	 */
	boolean autoRegister() default true;
}

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Inherited
@EnableDiscoveryClient
public @interface EnableEurekaClient {

}

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2、ImportSelector方式

@Target({ElementType.TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import({TransactionManagementConfigurationSelector.class})
public @interface EnableTransactionManagement {
    boolean proxyTargetClass() default false;

    AdviceMode mode() default AdviceMode.PROXY;

    int order() default 2147483647;
}

---

3、ImportBeanDefinitionRegistrar方式

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@SpringBootApplication
@EnableEurekaClient
@EnableZipkinServer
@EnableDiscoveryClient
public class Test_App {
  public static void main(String[] args) {
   SpringApplication.run(Test_App.class, args);
  }
}

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