SpringBoot整合MongoDB遇UnsatisfiedDependencyException报错求助

报错信息 #

初始报错：

ConfigServletWebServerApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'productController': Unsatisfied dependency expressed through field 'productServiceImpl'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.cts.eaution.impl.ProductServiceImpl' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

完整错误日志：

Error creating bean with name 'productController': Unsatisfied dependency expressed through field 'productService'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'productServiceImpl': Unsatisfied dependency expressed through field 'productRepository'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'productRepository' defined in com.cts.eauction.repository.ProductRepository defined in @EnableMongoRepositories declared on MongoRepositoriesRegistrar.EnableMongoRepositoriesConfiguration: Cannot resolve reference to bean 'mongoTemplate' while setting bean property 'mongoOperations'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'mongoTemplate' defined in class path resource [org/springframework/boot/autoconfigure/data/mongo/MongoDatabaseFactoryDependentConfiguration.class]: Unsatisfied dependency expressed through method 'mongoTemplate' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'mongoDatabaseFactory' defined in class path resource [org/springframework/boot/autoconfigure/data/mongo/MongoDatabaseFactoryConfiguration.class]: Bean instantiation via factory method failed; nested exception is org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.data.mongodb.core.MongoDatabaseFactorySupport]: Factory method 'mongoDatabaseFactory' threw exception; nested exception is java.lang.IllegalArgumentException: Database name must not contain slashes, dots, spaces, quotes, or dollar signs!

相关代码与配置 #

Controller类 #

@RestController
@RequestMapping("/e-auction/api/v1/seller/")
public class ProductController {
    
    @Autowired
    public ProductServiceImpl productServiceImpl;
    
/*  @Autowired
    public ProductRepository productRepository;
    */
    @GetMapping("/show-bids")
    public List<Product> getAllProducts() {
        System.out.println("Hello Product...");
        return productServiceImpl.findAll();
        //return productRepository.findAll();
    }
    
    
}

ServiceImpl类 #

class ProductServiceImpl implements ProductService {
    
    @Autowired
    private ProductRepository productRepository;

    @Override
    public List<Product> findAll() {
        return productRepository.findAll();
    }

}

Service接口 #

@Service
public interface ProductService {
    
    List<Product> findAll();

}

Repository接口 #

public interface ProductRepository extends MongoRepository<Product, String> {

}

POM.xml #

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <!-- <version>2.7.5</version> -->
        <version>2.6.13</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.cts</groupId>
    <artifactId>eauction</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>eauction</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
    <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-rest</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

application.properties配置 #

#server
server.port=8082
spring.data.mongodb.host=localhost
spring.data.mongodb.port=27017
spring.data.mongodb.database=productdb 

解决方案 #

从报错日志能定位到两个核心问题，逐一修正即可：

1. Service实现类未纳入Spring容器管理
   ProductServiceImpl类缺少@Service注解，导致Spring无法扫描并创建该类的Bean实例，Controller注入时找不到匹配对象。修改后的代码如下：

   @Service
   public class ProductServiceImpl implements ProductService {
       
       @Autowired
       private ProductRepository productRepository;
   
       @Override
       public List<Product> findAll() {
           return productRepository.findAll();
       }
   }
   

   同时建议Controller注入接口而非实现类，降低代码耦合：

   @Autowired
   public ProductService productService;
   

2. MongoDB数据库名包含非法空格
   报错提示数据库名不能包含空格，你的配置spring.data.mongodb.database=productdb 末尾多了一个空格，修改配置文件：

   spring.data.mongodb.database=productdb
   

完成以上两处修改后，重启应用即可解决启动报错问题。

内容的提问来源于stack exchange，提问作者Karthikeyan