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I am following this tutorial ( https://www.youtube.com/watch?v=Hu-cyytqfp8 ) and trying to connect to MongoDB on a remote server in Spring Boot. I get the following message when I run the application.
Description: Parameter 0 of constructor in com.mongotest.demo.Seeder required a bean of type 'com.mongotest.repositories.StudentRepository' that could not be found.
Action: Consider defining a bean of type 'com.mongotest.repositories.StudentRepository' in your configuration.
The project structure.
And here are my classes
@Document(collection = "Students")
public class Student {
@Id
private String number;
private String name;
@Indexed(direction = IndexDirection.ASCENDING)
private int classNo;
//Constructor and getters and setters.
}
================================
@Repository
public interface StudentRepository extends MongoRepository<Student, String>{
}
================================
@Component
@ComponentScan({"com.mongotest.repositories"})
public class Seeder implements CommandLineRunner{
private StudentRepository studentRepo;
public Seeder(StudentRepository studentRepo) {
super();
this.studentRepo = studentRepo;
}
@Override
public void run(String... args) throws Exception {
// TODO Auto-generated method stub
Student s1 = new Student("1","Tom",1);
Student s2 = new Student("2","Jerry",1);
Student s3 = new Student("3","Kat",2);
studentRepo.deleteAll();
studentRepo.save(Arrays.asList(s1,s2,s3));
}
}
================================
@SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.mongotest</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>demo</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.9.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.mongodb</groupId>
<artifactId>mongo-java-driver</artifactId>
<version>3.4.2</version>
</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-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>
745
Declaring a bean. To declare a bean, simply annotate a method with the @Bean annotation. When JavaConfig encounters such a method, it will execute that method and register the return value as a bean within a BeanFactory .
Annotating a class with the @Configuration indicates that the class can be used by the Spring IoC container as a source of bean definitions. The @Bean annotation tells Spring that a method annotated with @Bean will return an object that should be registered as a bean in the Spring application context.
Spring @Bean Annotation is applied on a method to specify that it returns a bean to be managed by Spring context. Spring Bean annotation is usually declared in Configuration classes methods. In this case, bean methods may reference other @Bean methods in the same class by calling them directly.
In Spring, the objects that form the backbone of your application and that are managed by the Spring IoC container are called beans. A bean is an object that is instantiated, assembled, and otherwise managed by a Spring IoC container. Otherwise, a bean is simply one of many objects in your application.
Please add below annotations in DemoApplication
@SpringBootApplication
@ComponentScan("com.mongotest") //to scan packages mentioned
@EnableMongoRepositories("com.mongotest") //to activate MongoDB repositories
public class DemoApplication { ... }
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