【报错】
Caused by: java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at java.net.URLClassLoader$1.run(Unknown Source)
at java.net.URLClassLoader$1.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at org.apache.tomcat.jdbc.pool.ClassLoaderUtil.loadClass(ClassLoaderUtil.java:38)
... 85 common frames omitted
===================================================
解决办法：
在工程主目录中build.gradle添加如下代码：
runtime "mysql:mysql-connector-java:5.1.38"
【参考】http://stackoverflow.com/questions/33968150/grails-3-0-9-classnotfoundexception-com-mysql-jdbc-driver
grails3.1.5 com.mysql.jdbc.Driver
原文：http://www.cnblogs.com/zhzhang/p/5396528.html