How to access a in-memory database in spring - spring-boot

Question

I am developing a standalone java application using in-memory embedded database. I refereed few documents and I wrote the following code. I am using spring Boot.
These are the steps I did so far:
In, pom file I added these dependencies.
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-jdbc</artifactId>
</dependency>
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.36</version>
</dependency>
In application.properties file
spring.datasource.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/test
spring.datasource.username=root
spring.datasource.password=admin
I created a scripts schema.sql and data.sql
schema.sql
CREATE TABLE users
(
id int(11) NOT NULL AUTO_INCREMENT,
name varchar(100) NOT NULL,
email varchar(100) DEFAULT NULL,
PRIMARY KEY (id)
);
data.sql
insert into users(id, name, email) values(1,'demouser','user#test.com');
Here is my repository class.
#Repository
public class UserRepository {
#Autowired
private JdbcTemplate jdbcTemplate;
#Transactional(readOnly = true)
public List<User> findAll() {
return jdbcTemplate.query("select * from users", new UserRowMapper());
}
class UserRowMapper implements RowMapper<User> {
#Override
public User mapRow(ResultSet rs, int rowNum) throws SQLException {
User user = new User();
user.setId(rs.getInt("id"));
user.setName(rs.getString("name"));
user.setEmail(rs.getString("email"));
return user;
}
Here is my junit class
#Autowired
private UserRepository userRepository;
private EmbeddedDatabase db;
#Before
public void setUp() {
// db = new EmbeddedDatabaseBuilder().addDefaultScripts().build();
Object db = new EmbeddedDatabaseBuilder().setType(EmbeddedDatabaseType.H2).addScript("schema.sql")
.addScript("data.sql").build();
}
#Test
public void findAllUsers() {
List<User> users = userRepository.findAll();
System.out.println(users.get(0).getName());
assertNotNull(users);
assertTrue(!users.isEmpty());
}
when I run my junit I am getting the following error.
org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'userRepository': Unsatisfied dependency expressed through field 'jdbcTemplate': Error creating bean with name 'org.springframework.boot.autoconfigure.jdbc.JdbcTemplateAutoConfiguration': Unsatisfied dependency expressed through constructor parameter 0: Error creating bean with name 'dataSource' defined in class path resource [org/springframework/boot/autoconfigure/jdbc/DataSourceConfiguration$Tomcat.class]: Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSourceInitializer': Invocation of init method failed; nested exception is org.springframework.jdbc.datasource.init.UncategorizedScriptException: Failed to execute database script; nested exception is org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
Do I have to add any other dependency or download a database.

Answer 1

Since you want to use In-memory database which is H2 so you shouldn't be having MySql dependecy in pom.xml and mysql related properties in application.properties.
Remove the MySql connector dependency from pom.xml
<!--Delete This-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.36</version>
And delete all the properties in application.properties file.
Keep it blank, Spring boot will auto-configure these properties for H2 database.
Checkout the complete Spring Boot JDBC Demo project in the GitHub repository.