What is the Difference Between `<context:component-scan>` and `<annotation-driven>` Tags in Spring MVC?

What is the difference between `<context:component-scan>` and `<annotation-driven>` tags in Spring MVC?

<context:component-scan base-package="com.mycompany.maventestwebapp" />

<annotation-driven />

In Spring MVC, both `<context:component-scan>` and `<annotation-driven>` serve different purposes in configuring the framework for handling requests and defining beans. It's important to understand their specific functions to effectively set up a Spring MVC application.

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd">

   <context:component-scan base-package="com.mycompany.maventestwebapp" />
   <mvc:annotation-driven />

</beans>

Causes

• The `<context:component-scan>` tag is used to automatically detect and register the Spring components (controllers, services, repositories, etc.) from a given package. It enables the scanning of classes for annotations like `@Controller`, `@Service`, etc. without having to declare them manually in the XML configuration.
• The `<annotation-driven>` tag activates Spring's MVC capabilities, specifically to support annotations like `@RequestMapping`, `@ResponseBody`, and others. This tag is essential for enabling automatic handling of `@Controller` annotations.

Solutions

• Use `<context:component-scan>` to specify the base package where Spring should search for annotated components to create and manage beans within the application context.
• Implement `<annotation-driven>` in your configuration to enable annotative-based request handling, providing a more flexible and streamlined model for dealing with MVC components.

Mistake: Not including `<annotation-driven>` in the configuration can lead to HTTP 404 errors, especially if your controllers rely on request mapping.

Solution: Always ensure that `<annotation-driven>` is present when working with annotations facing HTTP requests.

Mistake: Overlooking the correct package name in `<context:component-scan>` may result in components not being detected, leading to unregistered beans.

Solution: Double-check the base package in `<context:component-scan>` to ensure it correctly points to your annotated controller or service classes.