"" 中构造函数的参数 0 需要一个无法找到的类型为 "" 的 bean

Question

The @RestController and its setup works well. I hit a snag when I was trying to add the service to the controller and auto-wiring them.

As far as I know everything looks like they've been wired well: it builds fine, and the IDE can't detect any problems. But I seem to be lacking something because it won't run.

***************************
APPLICATION FAILED TO START
***************************

Description:

Parameter 0 of constructor in org.church.id.controller.ChapterController required a bean of type 'org.church.id.service.ChapterService' that could not be found.


Action:

Consider defining a bean of type 'org.church.id.service.ChapterService' in your configuration.

ChapterController.java

@RestController
@Log4j
public class ChapterController {

    @Getter
    private Map<Integer, Chapter> chapters;

    private ChapterService chapterService;

    @Autowired
    public ChapterController(ChapterService chapterService) {

        this.chapterService = chapterService;
    }

    public void loadChapters() throws SQLException {

        log.debug("Loading chapters...");

        if (chapters != null) {
            chapters.clear();
        }
        chapters = chapterService.findAll().stream().collect(Collectors.toMap(Chapter::getId, Function.identity()));
    }

    @GetMapping("/chapter/list")
    public String list() throws SQLException {

        if (chapters == null) {
            loadChapters();
        }
        return chapters.values().stream().map(Chapter::getName).collect(Collectors.joining(", "));
    }
}

Inside my applicationContext.xml (My bad. I originally typed pom.xml)

    ...
    <bean id="chapterController" class="org.church.id.controller.ChapterController">
        <constructor-arg name="chapterService" ref="chapterService"/>
    </bean>

    <bean id="chapterService" class="org.church.id.service.impl.ChapterServiceImpl">
        <constructor-arg name="config" ref="dbConfig"/>
        <constructor-arg name="addressUtil" ref="addressUtil"/>
    </bean>
    ...

The real pom.xml

        ...
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-autoconfigure</artifactId>
            <version>${spring.boot.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
            <version>${spring.boot.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <version>${spring.boot.version}</version>
            <scope>test</scope>
        </dependency>
        ...

ChapterServiceImpl.java

@Log4j
@AllArgsConstructor
@Setter
@Service
public class ChapterServiceImpl implements ChapterService {

    private DBConfig config;

    private AddressUtil addressUtil;
    ...
}

ChapterService.java (Interface)

public interface ChapterService extends Service<Chapter> {

    Collection<Chapter> findByCountry(Country country) throws SQLException;
}

I've looked around here but the following have /not/ worked for me

• [x] Adding (exclude = {DataSourceAutoConfiguration.class}) to @SpringBootApplication
• [x] Prepending @Qualifier("chapterService") to the constructor's param: ChapterService chapterService

Also to note: I've modified it to have only a default constructor, but the same type of error happens when I try to inject through a setter. I don't know what's wrong. :(

EDIT: MainClassController.java

@SpringBootApplication
public class MainClassController {

    private ClassInfo model;

    private HashMap<Integer, String> classMap;

    public MainClassController() {
        loadData();
    }

    public void loadData() {

    }

    public static void main(String[] args) {

        SpringApplication.run(MainClassController.class, args);
    }
}

Answer 1

A little background: I started my project years ago, but got side tracked and now picking it up again.

What worked for me was starting with a base spring-boot project and adding my classes and fixing as I went.

As what @JoãoDias linked in the comments: https://www.baeldung.com/spring-boot-start is where I got my base spring boot. (Check Spring Initializr in the article).

Also advised by@AbhijitSarkar was that "no one uses Spring XML config anymore" which actually is a reflection on when I started this project. Very perceptive too that he was able to get the hint that my problem was due to combined internet searches.