@Conditional与Condition接口

@Conditional来指定一定条件下注册组件对像，所有的条件必须实现org.springframework.context.annotation.Condition接口，重写matches方法，通过matches中的返回值(boolean)来决定组件是否注册。

下方案例依赖于Spring的依赖+Lombok

@Slf4j
public class Test1 {

    @Test
    public void t1() {
        ApplicationContext ac = new AnnotationConfigApplicationContext(MainCfg.class);
        System.out.println("\n\n\n\n\n");
        log.debug("{}", ac.getBean("person", Person.class));
        log.debug("{}", ac.getBean("person1", Person.class));
    }
}

@Configuration
class MainCfg {

    @Bean
    @Conditional(CustomCondition1.class)
    public Person person() {
        return new Person();
    }
    @Bean
    @Conditional(CustomCondition2.class)
    public Person person1() {
        return new Person();
    }
}

@Data
class Person {
    private String name;
    private int age;
}

@Slf4j
class CustomCondition1 implements Condition {
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        log.debug("自定义condition返回true，使用该注解部分应该被加载！");
        return true;
    }
}

@Slf4j
class CustomCondition2 implements Condition {
    @Override
    public boolean matches(ConditionContext context, AnnotatedTypeMetadata metadata) {
        log.debug("自定义condition返回false，使用该注解的部分不因该被加载！");
        return false;
    }
}