SpringBoot - Unsatisfied dependency expressed through field - spring

Question

I was trying for CRUD services using springboot with mongodb.
Getting error while running main application.
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)}
Controller class :
#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 class :
class ProductServiceImpl implements ProductService {
#Autowired
private ProductRepository productRepository;
#Override
public List<Product> findAll() {
return productRepository.findAll();
}
}
Service interface :
#Service
public interface ProductService {
List<Product> findAll();
}
Repository interface :
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>
I tried multiple option by adding annotation like (service, repository, component, componentscan) non of this solve the problem.
application properties :
#server
server.port=8082
spring.data.mongodb.host=localhost
spring.data.mongodb.port=27017
spring.data.mongodb.database=productdb
Full Error logs :
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!

Answer 1

You have to place the #Service annotation on the implementation and not on the interface in order to make it autodetected by the component scan. Like this:
#Service
class ProductServiceImpl implements ProductService {
#Autowired
private ProductRepository productRepository;
#Override
public List<Product> findAll() {
return productRepository.findAll();
}
}
Also you should ask for a bean of the interface type and not the implementation in your controller:
#RestController
#RequestMapping("/e-auction/api/v1/seller/")
public class ProductController {
#Autowired
public ProductService productService;
}
This way you can have different implementations of the same interface, also you should not use field injection unless you have a good reason to use it.

Answer 2

If the above solution didn't work then another way you can try is by putting -
#ComponentScan(basePackages = {"com.package.class", "com.package.anotherClass"})
in your main application class.
This will scan all your classes present inside the packages.