Service required a bean of type that could not be found

[Sam Peterson]

I'm working on a spring boot project (following this tutorial). Consequently, I'm relying on the Apache Derby database to store my data.
When I tried running my spring boot application, I got this error:

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

Description:

Field TR in sam.springboot.service.TopicService required a bean of type 'sam.springboot.dao.TopicRepo' that could not be found.

The injection point has the following annotations:
- @org.springframework.beans.factory.annotation.Autowired(required=true)


Action:

Consider defining a bean of type 'sam.springboot.dao.TopicRepo' in your configuration.


Here is my code:

CourseAPIdatabaseApp.java

package sam.springboot;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;

@SpringBootApplication
@EnableAutoConfiguration(exclude={DataSourceAutoConfiguration.class})
public class CourseAPIdatabaseApp {

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

TopicRepo.java

package sam.springboot.dao;

import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
import sam.springboot.model.TopicEntity;

@Repository
public interface TopicRepo extends CrudRepository<TopicEntity, Integer>{

}

TopicService.java

package sam.springboot.service;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import sam.springboot.dao.TopicRepo;
import sam.springboot.model.TopicEntity;
/*
 * Remember how we @Autowired the "private TopicService service" instance in the 
 * TopicController class. The @Service annotation connects all of that to the database. 
 */
@Service
public class TopicService {
	
	@Autowired
	private TopicRepo TR;
	
	public List<TopicEntity> getAllTopics(){
		List<TopicEntity> topics = new ArrayList<>();
		TR.findAll().forEach(topics::add);
		return topics;
	}
	
	public TopicEntity getTopic(String id) {
		List<TopicEntity> topics = getAllTopics();
		/*
		for(TopicEntity topic: topics) {
			if(topic.getId().equals(id)) {
				return topic;
			}
		}
		*/
		//lambda expression for comparing the topic id passed in for a match while 
		//iterating the existing topic ids:
		return topics.stream().filter(t -> t.getId().equals(id)).findFirst().get();
	}
	
	public void addTopic(TopicEntity topic) {
		TR.save(topic);
	}
	/*
	public void updateTopic(String id, TopicEntity topic) {
		for(int i = 0; i < topics.size(); i++) {
			TopicEntity t = topics.get(i);//for each topic int the ArrayList,
			if(t.getId().equals(id)) {//if the id matches the inputted id,
				topics.set(i, topic);//overwrite the topic with the updated topic.
				return;
			}
		}
	}
	*/
}

TopicController.java

package sam.springboot.controller;

import java.util.Arrays;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.PutMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import sam.springboot.model.TopicEntity;
import sam.springboot.service.TopicService;

@RestController
public class TopicController {
	
	@Autowired	
	private TopicService service;	
	
	@GetMapping("/topics")
	public List<TopicEntity> getAllTopics() {
		return service.getAllTopics();
	}
	
	@GetMapping("/topics/{id}")//To test this, we will give the id we want to look for in the URL instead of by user input.
								   //As an example, lets use the URL: localhost:8080/topics/Spring
	public TopicEntity getTopic(@PathVariable String id) {
		return service.getTopic(id);
	}
	
	//@RequestMapping(method=RequestMethod.POST, value="/topics")
	@PostMapping("/topics")
	public void addTopic(@RequestBody TopicEntity topic) {
		service.addTopic(topic);
	}
	/*
	@PutMapping("/topics/{id}")
	public void updateTopic(@RequestBody TopicEntity topic, @PathVariable String id) {
		service.updateTopic(id,topic);
	}
	*/
}

application.properties

spring.jpa.hibernate.hbm2ddl-auto=update
spring.jpa.show-sql=true
spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.OracleDialect
spring.datasource.driver-class-name=org.h2.Driver
#spring.datasource.url=jdbc.h2.mem.localhost
spring.datasource.url=http://localhost:8080
spring.datasource.username=admin

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>2.1.9.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>sam.springboot</groupId>
	<artifactId>maven-api-database</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>maven-api-database</name>
	<description>Springboot database connection</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-web</artifactId>
		</dependency>

		<dependency>
			<groupId>org.apache.derby</groupId>
			<artifactId>derby</artifactId>
			<scope>runtime</scope>
		</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>

What am I missing?

EDIT: here is my project structure by the way:

[Al Hobbs]

You should run with debug logs.  You will be able to see if its being made and any errors.

[Himai Minh]

Hi, Sam,
Can you try to annotate @EnableJpaRespositories(basePackages="sam.springboot.dao") in the CourseAPIdatabaseApp ?
This way, the repository can be enabled.

[Himai Minh]

Hi, Sam,
I have a second suggestion. Can you try to rebuild your project? How about right click on the project, select "Maven run..." and put "clean install" in the "Goal" ?
The reason why I am asking because I guess the spring boot data jpa is not on the classpath yet.

[Himai Minh]

Hi Sam,
One more thing you can try is to remove @Repository from the TopicRepo interface.

[Himai Minh]

Hi, Sam,
One more try is to use embedded h2 database instead of Derby. And also comment out each line of application.properties by adding # in front of each key/value pair.
Run the application and visit localhost:8080/topics

The pom.xml becomes like this:

<?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>2.1.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>demo</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>11</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <scope>runtime</scope>
            <optional>true</optional>
        </dependency>


        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <version>1.3.176</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </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>

Give a try to see if it works.