Unable to Autowire an interface which extends CRUD repository - spring

Question

I am new to spring boot and trying to build a demo app. I would like to connect to a mysql DB using hibernate and fetch contents from a table. This is what my project structure looks like:
The class DemoApplication.java looks like this:
package com.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}
The HibernateTestController.java looks like this:
package com.example.controllers;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import com.example.repositories.PatchRepository;
#Controller
public class HibernateTestController {
#Autowired
PatchRepository patchRepository;
#RequestMapping(value={"/hibernateTest"})
public ModelAndView home() {
//List<Patch> patches = patchRepository.findAll();
return new ModelAndView("hibernateTest");
}
}
The PatchRepository.java looks like this:
package com.example.repositories;
import java.util.List;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
import com.example.models.Patch;
#Repository
public interface PatchRepository extends CrudRepository<Patch, Long> {
List<Patch> findAll();
}
Now, whenever I start the application, I get an error saying:
*************************** APPLICATION FAILED TO START
Description:
Field patchRepository in
com.example.controllers.HibernateTestController required a bean of
type 'com.example.repositories.PatchRepository' that could not be
found.
Action:
Consider defining a bean of type
'com.example.repositories.PatchRepository' in your configuration.
I am not able to figure out why the Autowire for PatchRepository is not working. I think my project structure is right and that PatchRepository should automatically be detected by spring as a bean.
This is what the POM.xml looks like:
<?xml version="1.0" encoding="UTF-8"?>
http://maven.apache.org/xsd/maven-4.0.0.xsd">
4.0.0
<groupId>com.example</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>1.4.2.RELEASE</version>
<relativePath />
</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.springframework.boot</groupId>
<artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jersey</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</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>org.webjars</groupId>
<artifactId>jquery</artifactId>
<version>3.1.1-1</version>
</dependency>
<dependency>
<groupId>org.webjars</groupId>
<artifactId>bootstrap</artifactId>
<version>3.3.7</version>
</dependency>
<dependency>
<groupId>org.hibernate.javax.persistence</groupId>
<artifactId>hibernate-jpa-2.1-api</artifactId>
<version>1.0.0.Final</version>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-commons-core</artifactId>
<version>1.4.1.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework.data</groupId>
<artifactId>spring-data-jpa</artifactId>
<version>1.10.6.RELEASE</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

Answer 1

try using the repository scan in your DemoApplication class
#SpringBootApplication
#EnableJpaRepositories("com.example.repositories")
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}

Answer 2

lets try to add "#ComponentScan"
#SpringBootApplication
#ComponentScan("com.example")
public class DemoApplication {
public static void main(String[] args) {
SpringApplication.run(DemoApplication.class, args);
}
}

Answer 3

Be sure that you have
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
and
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
into your pom.xml
Proper configs
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
And your Patch class is annotated with #Entity and have an Id Attribute annotated with #Id.
Everything should work.

Answer 4

I refactored my code as follows and things worked:
package com.example.repositories;
import java.util.List;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
import com.example.models.Patch;
public interface PatchRepository extends CrudRepository<Patch, Long> {
List<Patch> findAll();
}
<?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.example</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>1.4.3.RELEASE</version>
<relativePath />
</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.webjars</groupId>
<artifactId>jquery</artifactId>
<version>3.1.1-1</version>
</dependency>
<dependency>
<groupId>org.webjars</groupId>
<artifactId>bootstrap</artifactId>
<version>3.3.7</version>
</dependency>
<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-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
spring.thymeleaf.cache: false
##DB connections##
spring.datasource.url=jdbc:mysql://localhost/testdb
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
# Keep the connection alive if idle for a long time (needed in production)
spring.datasource.testWhileIdle = true
spring.datasource.validationQuery = SELECT 1
# Hibernate Configuration
spring.jpa.hibernate.ddl-auto=update
packagesToScan=com.example
hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
hibernate.show_sql=false
hibernate.format_sql=true
# Naming strategy
spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy
entitymanager.packagesToScan=com.example
# Use spring.jpa.properties.* for Hibernate native properties (the prefix is
# stripped before adding them to the entity manager)
#logging.level.org.springframework.web=DEBUG
#logging.level.org.hibernate=DEBUG
package com.example.controllers;
import java.util.List;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.servlet.ModelAndView;
import com.example.models.Patch;
import com.example.repositories.PatchRepository;
#Controller
public class HibernateTestController {
#Autowired
PatchRepository patchRepository;
#RequestMapping(value={"/hibernateTest"})
public ModelAndView home() {
List<Patch> patches = patchRepository.findAll();
return new ModelAndView("hibernateTest");
}
}
Application.properties looks like this:
spring.thymeleaf.cache: false
##DB connections## spring.datasource.url=jdbc:mysql://localhost/testdb spring.datasource.username=root spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
# Keep the connection alive if idle for a long time (needed in production) spring.datasource.testWhileIdle = true
spring.datasource.validationQuery = SELECT 1
# Hibernate Configuration spring.jpa.hibernate.ddl-auto=update packagesToScan=com.example
hibernate.dialect=org.hibernate.dialect.MySQL5Dialect
hibernate.show_sql=false hibernate.format_sql=true
# Naming strategy spring.jpa.hibernate.naming-strategy = org.hibernate.cfg.ImprovedNamingStrategy
entitymanager.packagesToScan=com.example
# Use spring.jpa.properties.* for Hibernate native properties (the prefix is
# stripped before adding them to the entity manager)
#logging.level.org.springframework.web=DEBUG
#logging.level.org.hibernate=DEBUG