java - 找不到Spring Boot Bean类型

我正在Spring网站上关注此SpringBoot Demo，以学习如何创建一个可以接受上传的文件。我收到一条错误消息:

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

Description:

Parameter 0 of constructor in com.example.springdemouploadingfiles.FileUploadController required a bean of type 'com.example.springdemouploadingfiles.storage.StorageService' that could not be found.


Action:

Consider defining a bean of type 'com.example.springdemouploadingfiles.storage.StorageService' in your configuration.


Execution failed for task ':bootRun'.

Process 'command '/Applications/IntelliJ IDEA CE.app/Contents/jbr/Contents/Home/bin/java'' finished with non-zero exit value 1

我尝试通过将@Bean批注添加到FileUploadController来修复它。

我尝试添加以下依赖项implementation 'org.springframework.boot:spring-boot-starter-data-jpa'runtimeOnly 'com.h2database:h2'build.gradle

注意:我不想将数据库连接到此演示项目。该演示承认，它不是在此演示中尝试连接数据库，而是在生产环境中进行连接。

我尝试在Storage Service界面上方添加@Service批注。

我尝试在StorageService接口(interface)上方添加@Component。

我尝试在主应用程序类@ComponentScan("com.example.springdemouploadingfiles")上方添加SpringDemoUploadingFilesApplication.java批注。

无论如何，我很乐意为您解决此错误提供帮助，以便我可以运行演示。以下是我的配置。

build.gradle

plugins {
    id 'org.springframework.boot' version '2.2.6.RELEASE'
    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
    id 'java'
}

group = 'com.example'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = '1.8'

repositories {
    mavenCentral()
}

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-thymeleaf'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    runtimeOnly 'com.h2database:h2'
    testImplementation('org.springframework.boot:spring-boot-starter-test') {
        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
    }
}

test {
    useJUnitPlatform()
}

FileUploadController.java

@Controller
public class FileUploadController {

    private final StorageService storageService;

    @Autowired
    public FileUploadController(StorageService storageService) {
        this.storageService = storageService;
    }

SpringDemoUploadingFilesApplication.java

@SpringBootApplication
@EnableConfigurationProperties(StorageProperties.class)
public class SpringDemoUploadingFilesApplication {

    public static void main(String[] args) {
        SpringApplication.run(SpringDemoUploadingFilesApplication.class, args);
    }

    @Bean
    CommandLineRunner init(StorageService storageService) {
        return (args) -> {
            storageService.deleteAll();
            storageService.init();
        };
    }
}

StorageService接口(interface)

@Service
public interface StorageService {
// implements interface.
}

最佳答案

您可能缺少StorageService的实现:



您可以从以下内容开始:

@Service
public class StorageServiceImpl implements StorageService {
    // Implement all the methods from StorageService.
}