Spring boot JPA error in gradle build from docker

Question

I have a Gradle project, i added jpa to it with:

implementation group: 'org.springframework.boot', name: 'spring-boot-starter-data-jpa', version: '2.4.3'
implementation group: 'mysql', name: 'mysql-connector-java', version: '8.0.23'

And in application.properties i have added the following lines:

spring.datasource.url=jdbc:mysql://user:pass@localhost/dbname
spring.datasource.username=null
spring.datasource.password=null
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
### Hibernate Properties
spring.jpa.properties.hibernate.dialect = org.hibernate.dialect.MySQL5InnoDBDialect
spring.jpa.hibernate.ddl-auto = update

It's working fine when the mysql server is hosted on the machine. But when i am building my spring boot application inside the docker with ./gradlew build command, without hosting the mysql its giving me the exception:

oreApplicationTests > contextLoads() FAILED
    java.lang.IllegalStateException at DefaultCacheAwareContextLoaderDelegate.java:132
        Caused by: org.springframework.beans.factory.BeanCreationException at AbstractAutowireCapableBeanFactory.java:1796
            Caused by: javax.persistence.PersistenceException at AbstractEntityManagerFactoryBean.java:403
                Caused by: org.hibernate.exception.JDBCConnectionException at SQLStateConversionDelegate.java:112
                    Caused by: com.mysql.cj.jdbc.exceptions.CommunicationsException at SQLError.java:174
                        Caused by: com.mysql.cj.exceptions.CJCommunicationsException at NativeConstructorAccessorImpl.java:-2
                            Caused by: java.net.UnknownHostException at InetAddress.java:797

I don't want these errors during the build, I only want to turn on the mysql server when i will be using the jars. So i don't want these errors during the compile time.

Answer 1

I ran into a similar error when using MySQL. The solution for me was to add in the dialect to the.properties folder. I figured out the error was coming from JPA not knowing which dialect to use based on the database.

spring.jpa.database-platform=org.hibernate.dialect.{your dialect here}

Also keep in mind tests want to run with an in memory database by default so you need to wire up your tests to run as expected.