Why Can\'t My Spring Application Find My UserService Bean?

Addressing Issue: 'Field Required a Bean of Type That Could Not Be Found'

The error message, "Field userService in main.java.rest.UsersController required a bean of type 'main.java.service.UserService' that could not be found," indicates that the Spring application cannot find a registered bean of type 'main.java.service.UserService'.

Cause:

This issue arises when the Spring container cannot locate the bean definition for the specified type. Beans are normally defined using annotations like @Service, but when using MongoDB with Spring, you typically extend a repository interface from MongoRepository.

Solutions:

There are two possible solutions to resolve this issue:

Solution 1: Restructuring Project Structure

Move the UserService class into a package that is scanned by the Spring container. By default, Spring scans all packages under the base package where the @SpringBootApplication annotation is declared. If your main class is in com.example.something, move UserService to com.example.something.service.

Solution 2: Using @ComponentScan

Add the following line to your main class where the @SpringBootApplication annotation is declared:

<code class="java">@SpringBootApplication(scanBasePackages = {
    "com.example.something", // Your default scanned package
    "main.java.service"      // The package containing the UserService class
})</code>

This will explicitly include the "main.java.service" package in the bean scanning process.

The above is the detailed content of Why Can\'t My Spring Application Find My UserService Bean?. For more information, please follow other related articles on the PHP Chinese website!