JDBC configuires

databaseConnection.groovy

// PostgreSQL
@GrabConfig(systemClassLoader=true)
@Grab('postgresql:postgresql:9.0-801.jdbc4')
def sql = groovy.sql.Sql.newInstance(
  "jdbc:postgresql://host.example.org/database",
  "username", "password", "org.postgresql.Driver")

// MySQL
@GrabConfig(systemClassLoader=true)
@Grab('mysql:mysql-connector-java:5.1.12')
def sql = groovy.sql.Sql.newInstance(
  "jdbc:mysql://host.example.org/database",
  "username", "password", "com.mysql.jdbc.Driver")

// MS SQL Server
@GrabConfig(systemClassLoader=true)
@Grab('net.sourceforge.jtds:jtds:1.2.2')
def sql = groovy.sql.Sql.newInstance(
  "jdbc:jtds:sqlserver://host.example.org/database",
  "username", "password", "net.sourceforge.jtds.jdbc.Driver")

// HSQLDB embedded
@GrabConfig(systemClassLoader=true)
@Grab('org.hsqldb:hsqldb:2.0.0')
def sql = groovy.sql.Sql.newInstance(
  "jdbc:hsqldb:mem:database", "sa", "", "org.hsqldb.jdbcDriver")

// H2 embedded
@GrabConfig(systemClassLoader=true)
@Grab('com.h2database:h2:1.3.148')
def sql = groovy.sql.Sql.newInstance(
  "jdbc:h2:mem:database", "sa", "", "org.h2.Driver")