根本原因是无法加载JDBC驱动程序类com.microsoft.sqlserver.jdbc.SQLServerDriver '

这是因为您的驱动程序在类路径中缺失。在SQL Server的情况下，您需要将jar复制到lib文件夹中。

在其他情况下，例如MySQL，您可以声明为maven依赖项。 b $ b

I was following the tutorial below but there must be some significant steps where knowledge, that I don't have, is being assumed.

http://padcom13.blogspot.co.uk/2011/01/setting-up-sql-server-2008-express-to.html

below is the setup in my datasource.groovy

username = "sa"
password = ""
url = "jdbc:sqlserver://localhost:1433;databaseName=Sandpit"
driverClassName = "com.microsoft.sqlserver.jdbc.SQLServerDriver"
dialect = "org.hibernate.dialect.SQLServerDialect"

and below is the error popping up on run app command

ERROR context.GrailsContextLoader  - Error executing bootstraps: 
Error creating bean with name 'transactionManagerPostProcessor': 
Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'transactionManager': 
Cannot resolve reference to bean 'sessionFactory' while setting bean property 'sessionFactory'; 
nested exception is org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'sessionFactory': 
Cannot resolve reference to bean 'lobHandlerDetector' while setting bean property 'lobHandler'; 
nested exception is org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'lobHandlerDetector': Invocation of init method failed; 
nested exception is org.springframework.jdbc.support.MetaDataAccessException: 
Error while extracting DatabaseMetaData; nested exception is org.apache.commons.dbcp.SQLNestedException: 
Cannot load JDBC driver class 'com.microsoft.sqlserver.jdbc.SQLServerDriver'
Message: Error creating bean with name 'transactionManagerPostProcessor': 
Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'transactionManager': Cannot resolve reference to bean 'sessionFactory' 
while setting bean property 'sessionFactory'; nested exception is 
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sessionFactory': 
Cannot resolve reference to bean 'lobHandlerDetector' while setting bean property 'lobHandler'; 
nested exception is org.springframework.beans.factory.BeanCreationException: 
Error creating bean with name 'lobHandlerDetector': 
Invocation of init method failed; nested exception is 
org.springframework.jdbc.support.MetaDataAccessException: 
Error while extracting DatabaseMetaData; nested exception is 
org.apache.commons.dbcp.SQLNestedException: 
Cannot load JDBC driver class 'com.microsoft.sqlserver.jdbc.SQLServerDriver'

Been working on this a couple of days without seeing my app run..... any advice?

The root cause is Cannot load JDBC driver class 'com.microsoft.sqlserver.jdbc.SQLServerDriver'

That's because your driver is missing in the classpath. In the case of SQL Server you need to copy the jar to the lib folder.

In other cases like MySQL you can declare as a maven dependency.