How to use spring boot app1 into spring boot app2 as dependency where spring boot app1 is doing some DB operation?

Question

I am trying to create a spring boot app jar file which I need to use in another spring boot app. spring boot app1 is doing some DB operation. I want to add spring boot app1 to my spring boot app2 as a dependency and want to call service method which makes DB operations using MongoRepository.

I am attaching my code below. Can some help me with my problem?

Error:

  .   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::                (v2.7.7)

2023-01-06 22:51:27.472  INFO 13892 --- [           main] com.example.apptwo.ApptwoApplication     : Starting ApptwoApplication using Java 17.0.1 on HP with PID 13892 (C:\Users\saurabh\Desktop\apptwo\apptwo\target\classes started by saurabh in C:\Users\saurabh\Desktop\apptwo\apptwo)
2023-01-06 22:51:27.475  INFO 13892 --- [           main] com.example.apptwo.ApptwoApplication     : No active profile set, falling back to 1 default profile: "default"
2023-01-06 22:51:27.926  INFO 13892 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Bootstrapping Spring Data MongoDB repositories in DEFAULT mode.
2023-01-06 22:51:27.939  INFO 13892 --- [           main] .s.d.r.c.RepositoryConfigurationDelegate : Finished Spring Data repository scanning in 8 ms. Found 0 MongoDB repository interfaces.
2023-01-06 22:51:28.178  WARN 13892 --- [           main] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'appTwoService': Unsatisfied dependency expressed through field 'service'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'appone': Unsatisfied dependency expressed through field 'repo'; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'com.example.appone.repo.PersonRepo' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
2023-01-06 22:51:28.191  INFO 13892 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2023-01-06 22:51:28.217 ERROR 13892 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

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

Description:

Field repo in com.example.appone.service.PersonService required a bean of type 'com.example.appone.repo.PersonRepo' 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 'com.example.appone.repo.PersonRepo' in your configuration.

APP1

package com.example.appone.entity;

import lombok.ToString;
import org.springframework.data.annotation.Id;
import org.springframework.data.mongodb.core.mapping.Document;

@Document(collection = "test1")
@ToString
public class Person {
    @Id
    private String _id;
    private String name;
    private String email;
}

package com.example.appone.repo;

import com.example.appone.entity.Person;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.stereotype.Repository;

@Repository
public interface PersonRepo extends MongoRepository<Person, String> {
}

package com.example.appone.service;

import com.example.appone.entity.Person;
import com.example.appone.repo.PersonRepo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

import java.util.List;

@Component
public class PersonService implements CommandLineRunner {

    @Autowired
    private PersonRepo repo;

    public List<Person> getAllTest() {
        return repo.findAll();
    }

    @Override
    public void run(String... args) throws Exception {
        System.out.println(getAllTest());
    }
}

application.properties

spring.data.mongodb.uri=mongodb://localhost:27017/DB1
spring.data.mongodb.database=DB1

APP2

package com.example.apptwo.service;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.example.appone.service.PersonService;

@Configuration
public class AppOneConfig {

    @Bean
    public PersonService appone() {
        return new PersonService();
    }
}

package com.example.apptwo.service;

import com.example.appone.service.PersonService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

@Component
public class AppTwoService implements CommandLineRunner {
    
    @Autowired
    private PersonService service;

    @Override
    public void run(String... args) throws Exception {
        System.out.println(service.getAllTest());
    }
}

<?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>2.7.7</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>apptwo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>apptwo</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>17</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-mongodb</artifactId>
        </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>

        <dependency>
            <groupId>com.example</groupId>
            <artifactId>appone</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

I tried @Autowired but it did not worked then I created a config file where I am creating bean of the service class of app1, This time bean found for app1 service class but bean not found for repository interface.

Answer 1

Please remove this class from APP2.

@Configuration
public class AppOneConfig {

    @Bean
    public PersonService appone() {
        return new PersonService();
    }
}

and add scanBasePackages attribute in @SpringBootApplication annotation in APP2 main class like this and try again.

@SpringBootApplication(scanBasePackages = {"com.example.appone","com.example.apptwo"})
public class SpringBootDemoApplication {

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

}