@Autowired 在多模块应用程序中不起作用

Question

I need to @Autowire database services or repositores form "database" module in "game" module. Already added those annotations in main "Application" class:

@Configuration
@EnableMethodSecurity
@SpringBootApplication
@EnableAutoConfiguration
@EntityScan(basePackages="com.rydzwr.tictactoe")
@ComponentScan(basePackages="com.rydzwr.tictactoe")
@EnableJpaRepositories(basePackages="com.rydzwr.tictactoe")
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

Adding them in constructor is much more difficult, becouse I'm need to create list of instances of those classes in StrategySelector:

@Service
public class GameStrategySelector {
    private final List<BuildGameStrategy> strategyList = asList(
           new LocalPlayerGameStrategy(),
            new MultiPlayerGameStrategy()
    );

    public BuildGameStrategy chooseStrategy(GameDto gameDto) {
        return strategyList
                .stream()
                .filter(strategy -> strategy.applies(gameDto))
                .findFirst()
                .orElse(new ErrorGameTypeStrategy());
    }
}

Or, maybe someone has better idea, for StrategySelector logic?

Here is class with given problem:

@Component
public class LocalPlayerGameStrategy implements BuildGameStrategy {
    @Autowired
    private GameService gameService;
    @Autowired
    private UserService userService;
    @Autowired
    private PlayerService playerService;

    @Override
    @Transactional
    public void buildGame(GameDto gameDto) {
        Game game = new GameBuilder(gameDto.getGameSize(), gameDto.getGameDifficulty()).build();
        gameService.save(game);

        User caller = userService.findByName(SecurityContextHolder.getContext().getAuthentication().getName());
        assert caller != null;

        for (PlayerDto playerDto : gameDto.getPlayers()) {
            Player player = new PlayerBuilder().setGame(game).setUser(caller).setPlayerDetails(playerDto).build();
            playerService.save(player);
        }

        game.setState(GameState.IN_PROGRESS);

        gameService.save(game);
    }


    @Override
    public boolean applies(GameDto gameDto) {
        return gameDto.getPlayers().stream().allMatch(p -> p.getPlayerType().equals(PlayerType.LOCAL.name()));
    }
}

I tried to autowire repositores and services with implemented logic as well. Every time all of them:

@Autowired
    private GameService gameService;
    @Autowired
    private UserService userService;
    @Autowired
    private PlayerService playerService;

ARE NULL

I tried everything I found on google

Answer 1

You can't create new instances of LocalPlayerGameStrategy and MultiPlayerGameStrategy inside GameStrategySelector they won't be spring beans so they can't @Autowire other beans.

Modify your GameStrategySelector to inject all BuildGameStrategy instead of creating them manually

@Service
public class GameStrategySelector {
    private final List<BuildGameStrategy> strategyList;
    
    public GameStrategySelector(List<BuildGameStrategy> allStrategies){
        strategyList = allStrategies;
    }

    public BuildGameStrategy chooseStrategy(GameDto gameDto) {
        return strategyList
                .stream()
                .filter(strategy -> strategy.applies(gameDto))
                .findFirst()
                .orElse(new ErrorGameTypeStrategy());
    }
}