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source/_posts/ATipInSpringIOC.md

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+---
+title: A tip in Spring IOC
+date: 2024-05-02 14:35:53
+tags: Tips
+categories: Coding Tips
+---
+
+These days, I'm learning how Apache Kafka is used in Springboot. And I found an interesting tip in Springboot ioc.
+
+<!--more-->
+
+Before, I injected the bean into another bean like this:
+
+```java
+@Service
+public class KafkaProducer {
+
+    private KafkaTemplate<String, String> kafkaTemplate;
+
+    @Autowired
+    public KafkaProducer(KafkaTemplate<String, String> kafkaTemplate) {
+        this.kafkaTemplate = kafkaTemplate;
+    }
+}
+```
+
+Or like this:
+
+```java
+@Service
+public class KafkaProducer {
+
+    @Autowired
+    private KafkaTemplate<String, String> kafkaTemplate;
+}
+```
+
+But, when I learned with this tutorial, the author inject the `kafkaTemplate` like this:
+
+```java
+@Service
+public class KafkaProducer {
+
+    private KafkaTemplate<String, String> kafkaTemplate;
+
+    public KafkaProducer(KafkaTemplate<String, String> kafkaTemplate) {
+        this.kafkaTemplate = kafkaTemplate;
+    }
+}
+```
+
+In other words, this way of injecting without `@Autowired`, made me feel amazed.
+
+He said Spring framework will automatically inject this dependency(`kafkaTemplate`) whenever this bean(`KafkaProducer`) has only one parameterized constructor. I think is a useful and elegant way.