这是不正确的。如果你使用@Configuration而不使用proxyBeanMethods = false：

/**
 * Specify whether {@code @Bean} methods should get proxied in order to enforce
 * bean lifecycle behavior, e.g. to return shared singleton bean instances even
 * in case of direct {@code @Bean} method calls in user code. This feature
 * requires method interception, implemented through a runtime-generated CGLIB
 * subclass which comes with limitations such as the configuration class and
 * its methods not being allowed to declare {@code final}.
 * <p>The default is {@code true}, allowing for 'inter-bean references' via direct
 * method calls within the configuration class as well as for external calls to
 * this configuration's {@code @Bean} methods, e.g. from another configuration class.
 * If this is not needed since each of this particular configuration's {@code @Bean}
 * methods is self-contained and designed as a plain factory method for container use,
 * switch this flag to {@code false} in order to avoid CGLIB subclass processing.
 * <p>Turning off bean method interception effectively processes {@code @Bean}
 * methods individually like when declared on non-{@code @Configuration} classes,
 * a.k.a. "@Bean Lite Mode" (see {@link Bean @Bean's javadoc}). It is therefore
 * behaviorally equivalent to removing the {@code @Configuration} stereotype.
 * @since 5.2
 */
boolean proxyBeanMethods() default true;

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然后这个类中的所有@Bean方法都被代理，每当我们调用它们时，示例只创建一次。
参数注入确实更好，因为我们不通过代理，但这已经超出了Spring for Apache Kafka的范围。我相信那些bean方法调用风格的示例更适合理解而不是性能等。
这也是一个事实，使用Sping Boot ，你可能不需要那些工厂bean，因为它们只是自动配置的。然而，这并不意味着你总是使用Sping Boot 。因此，普通的Spring for Apache Kafka示例往往充满了信息。