SpringBoot 实现自定义的 @ConditionalOnXXX 注解示例详解

// 派生注解
@Retention(RetentionPolicy.RUNTIME)
@Target({ ElementType.TYPE, ElementType.METHOD })
@Documented
@Conditional(CustomConditional.class)
public @interface ConditionalOnCustom {
    String[] value() default {};
}

public class CustomConditional implements Condition {

	@Override
	public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
		// 获取到自定义注解中的 value 值
		String[] properties = (String[]) metadata.getAnnotationAttributes("smoketest.test.condition.ConditionalOnCustom").get("value");
		// 遍历自定义属性的 value 值
		for (String property : properties) {
			// 获取定义在配置文件中的值，并且 equals("customBean") 则返回 true
			if ("customBean".equals(context.getEnvironment().getProperty(property))) {
				return true;
			}
		}
		return false;
	}
}

@Component
@ConditionalOnCustom({"smoketest.test.condition.bean"})
public class ConditionalUse {
}

smoketest.test.condition.bean = customBean

@SpringBootApplication
@ConfigurationPropertiesScan
public class SampleTestApplication {

	public static void main(String[] args) {
		ConfigurableApplicationContext context = SpringApplication.run(SampleTestApplication.class, args);
		ConditionalUse bean = context.getBean(ConditionalUse.class);
		System.out.println(bean);
	}

}