环境：
Kettle：kettle-spoon 版本stable release -4.3.0
Mysql：MySQL Server 5.5
数据库连接信息：
测试数据库连接情况。
错误连接数据库 [MySql-1] :org.pentaho.di.core.exception.KettleDatabaseException:
Erroroccured while trying to connect to the database
Exceptionwhile loading class
org.gjt.mm.mysql.Driver
org.pentaho.di.core.exception.KettleDatabaseException:
Erroroccured while trying to connect to the database
Exceptionwhile loading class
org.gjt.mm.mysql.Driver
atorg.pentaho.di.core.database.Database.normalConnect(Database.java:368)
at org.pentaho.di.core.database.Database.connect(Database.java:317)
atorg.pentaho.di.core.database.Database.connect(Database.java:279)
atorg.pentaho.di.core.database.Database.connect(Database.java:269)
atorg.pentaho.di.core.database.DatabaseFactory.getConnectionTestReport(DatabaseFactory.java:86)
atorg.pentaho.di.core.database.DatabaseMeta.testConnection(DatabaseMeta.java:2464)
atorg.pentaho.ui.database.event.DataHandler.testDatabaseConnection(DataHandler.java:533)
atsun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
atsun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
atsun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
atjava.lang.reflect.Method.invoke(Unknown Source)
atorg.pentaho.ui.xul.impl.AbstractXulDomContainer.invoke(AbstractXulDomContainer.java:329)
atorg.pentaho.ui.xul.impl.AbstractXulComponent.invoke(AbstractXulComponent.java:139)
atorg.pentaho.ui.xul.impl.AbstractXulComponent.invoke(AbstractXulComponent.java:123)
atorg.pentaho.ui.xul.swt.tags.SwtButton.access$500(SwtButton.java:26)
atorg.pentaho.ui.xul.swt.tags.SwtButton$4.widgetSelected(SwtButton.java:119)
atorg.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
atorg.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
atorg.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
atorg.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
atorg.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
atorg.eclipse.jface.window.Window.runEventLoop(Window.java:820)
atorg.eclipse.jface.window.Window.open(Window.java:796)
atorg.pentaho.ui.xul.swt.tags.SwtDialog.show(SwtDialog.java:378)
atorg.pentaho.ui.xul.swt.tags.SwtDialog.show(SwtDialog.java:304)
atorg.pentaho.di.ui.core.database.dialog.XulDatabaseDialog.open(XulDatabaseDialog.java:115)
atorg.pentaho.di.ui.core.database.dialog.DatabaseDialog.open(DatabaseDialog.java:62)
atorg.pentaho.di.ui.spoon.delegates.SpoonDBDelegate.editConnection(SpoonDBDelegate.java:88)
at org.pentaho.di.ui.spoon.Spoon.doubleClickedInTree(Spoon.java:2792)
atorg.pentaho.di.ui.spoon.Spoon.access$1900(Spoon.java:310)
atorg.pentaho.di.ui.spoon.Spoon$24.widgetDefaultSelected(Spoon.java:5275)
atorg.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(UnknownSource)
atorg.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
atorg.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
atorg.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
at org.pentaho.di.ui.spoon.Spoon.readAndDispatch(Spoon.java:1183)
atorg.pentaho.di.ui.spoon.Spoon.start(Spoon.java:6968)
atorg.pentaho.di.ui.spoon.Spoon.main(Spoon.java:567)
atsun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(UnknownSource)
atsun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
atjava.lang.reflect.Method.invoke(Unknown Source)
atorg.pentaho.commons.launcher.Launcher.main(Launcher.java:134)
Causedby: org.pentaho.di.core.exception.KettleDatabaseException:
Exceptionwhile loading class
org.gjt.mm.mysql.Driver
atorg.pentaho.di.core.database.Database.connectUsingClass(Database.java:423)
atorg.pentaho.di.core.database.Database.normalConnect(Database.java:352)
... 43 more
Causedby: java.lang.ClassNotFoundException: org.gjt.mm.mysql.Driver
atjava.net.URLClassLoader$1.run(Unknown Source)
atjava.net.URLClassLoader$1.run(Unknown Source)
atjava.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(UnknownSource)
atjava.lang.ClassLoader.loadClass(Unknown Source)
atjava.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(NativeMethod)
at java.lang.Class.forName(UnknownSource)
at org.pentaho.di.core.database.Database.connectUsingClass(Database.java:414)
... 44 more
主机名 : 192.168.2.1
端口 : 3306
数据库名:test
内事不决问百度，外事不决问谷歌。那就问问吧。
将对应的mysql驱动包（mysql-connector-java-5.1.15-bin.jar）放到下kettle的目录：data-integration\lib\下。
下载地址：http://dev.mysql.com/downloads/connector/j/
重启再次进行连接测试通过。