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第一次用Kettle连接MySQL数据库时，报下面错误，

错误信息，

错误连接数据库 [mysqllocal] : org.pentaho.di.core.exception.KettleDatabaseException: Error occurred while trying to connect to the databaseDriver class 'org.gjt.mm.mysql.Driver' could not be found, make sure the 'MySQL' driver (jar file) is installed.org.gjt.mm.mysql.Driverorg.pentaho.di.core.exception.KettleDatabaseException: Error occurred while trying to connect to the databaseDriver class 'org.gjt.mm.mysql.Driver' could not be found, make sure the 'MySQL' driver (jar file) is installed.org.gjt.mm.mysql.Driver	at org.pentaho.di.core.database.Database.normalConnect(Database.java:477)	at org.pentaho.di.core.database.Database.connect(Database.java:373)	at org.pentaho.di.core.database.Database.connect(Database.java:344)	at org.pentaho.di.core.database.Database.connect(Database.java:334)	at org.pentaho.di.core.database.DatabaseFactory.getConnectionTestReport(DatabaseFactory.java:83)	at org.pentaho.di.core.database.DatabaseFactory.getConnectionTestResults(DatabaseFactory.java:112)	at org.pentaho.di.core.database.DatabaseMeta.testConnectionSuccess(DatabaseMeta.java:2843)	at org.pentaho.ui.database.event.DataHandler.testDatabaseConnection(DataHandler.java:631)	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)	at java.lang.reflect.Method.invoke(Method.java:497)	at org.pentaho.ui.xul.impl.AbstractXulDomContainer.invoke(AbstractXulDomContainer.java:313)	at org.pentaho.ui.xul.impl.AbstractXulComponent.invoke(AbstractXulComponent.java:157)	at org.pentaho.ui.xul.impl.AbstractXulComponent.invoke(AbstractXulComponent.java:141)	at org.pentaho.ui.xul.swt.tags.SwtButton.access$500(SwtButton.java:43)	at org.pentaho.ui.xul.swt.tags.SwtButton$4.widgetSelected(SwtButton.java:137)	at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)	at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)	at org.eclipse.swt.widgets.Display.sendEvent(Unknown Source)	at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)	at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)	at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)	at org.eclipse.jface.window.Window.runEventLoop(Window.java:820)	at org.eclipse.jface.window.Window.open(Window.java:796)	at org.pentaho.di.ui.xul.KettleDialog.show(KettleDialog.java:89)	at org.pentaho.di.ui.xul.KettleDialog.show(KettleDialog.java:56)	at org.pentaho.di.ui.core.database.dialog.XulDatabaseDialog.open(XulDatabaseDialog.java:117)	at org.pentaho.di.ui.core.database.dialog.DatabaseDialog.open(DatabaseDialog.java:61)	at org.pentaho.di.ui.spoon.delegates.SpoonDBDelegate.editConnection(SpoonDBDelegate.java:96)	at org.pentaho.di.ui.spoon.Spoon.doubleClickedInTree(Spoon.java:3139)	at org.pentaho.di.ui.spoon.Spoon.doubleClickedInTree(Spoon.java:3074)	at org.pentaho.di.ui.spoon.Spoon.access$1700(Spoon.java:372)	at org.pentaho.di.ui.spoon.Spoon$26.widgetDefaultSelected(Spoon.java:6335)	at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)	at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)	at org.eclipse.swt.widgets.Display.sendEvent(Unknown Source)	at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)	at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)	at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)	at org.pentaho.di.ui.spoon.Spoon.readAndDispatch(Spoon.java:1384)	at org.pentaho.di.ui.spoon.Spoon.waitForDispose(Spoon.java:7949)	at org.pentaho.di.ui.spoon.Spoon.start(Spoon.java:9331)	at org.pentaho.di.ui.spoon.Spoon.main(Spoon.java:710)	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)	at java.lang.reflect.Method.invoke(Method.java:497)	at org.pentaho.commons.launcher.Launcher.main(Launcher.java:92)Caused by: org.pentaho.di.core.exception.KettleDatabaseException: Driver class 'org.gjt.mm.mysql.Driver' could not be found, make sure the 'MySQL' driver (jar file) is installed.org.gjt.mm.mysql.Driver	at org.pentaho.di.core.database.Database.connectUsingClass(Database.java:520)	at org.pentaho.di.core.database.Database.normalConnect(Database.java:461)	... 48 moreCaused by: java.lang.ClassNotFoundException: org.gjt.mm.mysql.Driver	at java.net.URLClassLoader.findClass(URLClassLoader.java:381)	at java.lang.ClassLoader.loadClass(ClassLoader.java:424)	at java.lang.ClassLoader.loadClass(ClassLoader.java:357)	at org.pentaho.di.core.database.Database.connectUsingClass(Database.java:495)	... 49 more主机名       : 127.0.0.1端口           : 3306数据库名:mytest

原因很简单，缺少mysql的connector jar包。然后在lib目录下引入jar即可。

引入connector jar之后，需要重启kettle，然后测试，连接成功。

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