can't connect grails application to a mySql database, Cannot load JDBC driver class 'com.mysql.jdbc.Driver'

Question

I already copied the mysql/j connector to the grails-app/lib folder of my grails application. and my DataSource.groovy file looks like this

dataSource {
    pooled = true
    driverClassName = "com.mysql.jdbc.Driver"
    username = "root"
    password = "password"
}
hibernate {
    cache.use_second_level_cache = true
    cache.use_query_cache = false
    cache.region.factory_class = 'net.sf.ehcache.hibernate.EhCacheRegionFactory'
}
// environment specific settings
environments {
    development {
        dataSource {
            dbCreate = "create-drop" // one of 'create', 'create-drop', 'update',     'validate', ''
            url = "jdbc:mysql://localhost:3306/tewhareoteata3test"
            dialect = "org.hibernate.dialect.MySQL5InnoDBDialect"
        }
    }
    test {
        dataSource {
            dbCreate = "update"
            url = "jdbc:h2:mem:testDb;MVCC=TRUE;LOCK_TIMEOUT=10000"
        }
    }
    production {
        dataSource {
            dbCreate = "update"
            url = "jdbc:h2:prodDb;MVCC=TRUE;LOCK_TIMEOUT=10000"
            pooled = true
            properties {
               maxActive = -1
               minEvictableIdleTimeMillis=1800000
               timeBetweenEvictionRunsMillis=1800000
               numTestsPerEvictionRun=3
               testOnBorrow=true
               testWhileIdle=true
               testOnReturn=true
               validationQuery="SELECT 1"
            }
        }
    }
}

but it gives me this error

Cannot load JDBC driver class 'com.mysql.jdbc.Driver'

Answer 1

In BuildConfig.groovy add

dependencies {
        runtime 'mysql:mysql-connector-java:5.1.16'
    }

In fact it may be there already just commented out.

This tells grails to download mysql-connector and its dependencies.

You'll need to tell Grails which maven repositories to use (also in BuildConfig.groovy ) :

repositories {
        grailsPlugins()
        grailsHome()
        grailsCentral()
        mavenCentral()
    }

Answer 2

Uncomment

runtime 'mysql:mysql-connector-java:5.1.20'

in BuildConfig.groovy.

Answer 3

If you want to include jar files without using automatic dependency resolution, you need to put it in the lib directory in the project root, not grails-app/lib. The layout should look like this:

|-- grails-app
|   |-- conf
|   |   |-- hibernate
|   |   `-- spring
|   |-- controllers
|   |-- domain
|   |-- i18n
|   |-- services
|   |-- taglib
|   |-- utils
|   `-- views
|       `-- layouts
|-- lib                  <-- jars go here
|-- scripts
|-- src
|   |-- groovy
|   `-- java
|-- target
|-- test
|   |-- integration
|   `-- unit
`-- web-app