WebSocket in Spring Boot app Could not autowire error - spring-boot

Question

I have a spring boot app that I want to handle both rest calls and websockets. In my RestController I am able to define an instance of my GameUnitService as autowired, and it works as expected. ie: Gets populated and I can use it.
#Autowired private GameUnitService gameUnitService;
But when I try to autowire the above service in my websocket config, I get the error Could not autowire. No beans of 'GameUnitService' type found.. No error on the ApplicationContext.
However when I run the app after I remove the autowired from GameUnitService, the appContext is null when McpWebSocketConfig gets constructed.
#Configuration
#EnableWebSocket
public class McpWebSocketConfig implements WebSocketConfigurer {
private static final Logger log = LoggerFactory.getLogger(McpWebSocketConfig.class);
#Autowired private GameUnitService gameUnitService; //error: Could not autowire
#Autowired private ApplicationContext appContext; //this will end up null
public McpWebSocketConfig() {
//appContext is null
}
#Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(new McpWebSocketHandler(), "/socket").setAllowedOrigins("*");
registry.addHandler(new McpWebSocketHandler(), "/").setAllowedOrigins("*");
}
I had also tried moving the GameUnitService into the handler, and while the bean error was no longer present, the gameUnitService is null.
public class McpWebSocketHandler extends AbstractWebSocketHandler {
#Autowired
private GameUnitService gameUnitService;
public McpWebSocketHandler() {
// gameUnitService is null
}

Answer 1

To find the bean (You will need the bean of GameUnitService for Autowire), you need to enable the behavior to scan your classpath which spring does not do by default.
#ComponentScan is the annotation to scan for components declared in your code . by default, #ComponentScan only scans the package and all the sub-packages of its annotated class.
This means you need to tell the #ComponentScan to scan different packages,
preferably your root package .
So you will need an additional annotation.
#ComponentScan(basePackageClasses = ApplicationLauncher.class)
ApplicationLauncher is the class annotated with #SpringBootApplication
Change your configuration class to read like so:
#Configuration
#EnableWebSocket
#ComponentScan(basePackageClasses = ApplicationLauncher.class)
public class McpWebSocketConfig implements WebSocketConfigurer {
private static final Logger log = LoggerFactory.getLogger(McpWebSocketConfig.class);
#Autowired private GameUnitService gameUnitService; //error: Could not autowire
#Autowired private ApplicationContext appContext; //this will end up null
public McpWebSocketConfig() {
//appContext is null
}
#Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(new McpWebSocketHandler(), "/socket").setAllowedOrigins("*");
registry.addHandler(new McpWebSocketHandler(), "/").setAllowedOrigins("*");
}