我使用macbook pro和最新版本mojave for localhost我使用xampp服务器，当我想连接db时，消息如下：

Error connecting to database [LAB_DW]:org.pentaho.di.core.exception.KettleDatab        aseException: 
     Error occurred while trying to connect to the  database

    Error connecting to database: (using class org.gjt.mm.mysql.Driver)
    Communications link failure

    The last packet sent successfully to the server was 0 milliseconds ago. The driver has not   received any packets from the server.

    org.pentaho.di.core.exception.KettleDatabaseException: 
    Error occurred while trying to connect to the database
    Error connecting to database: (using class org.gjt.mm.mysql.Driver)
    Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

        at org.pentaho.di.core.database.Database.normalConnect(Database.java:472)
        at org.pentaho.di.core.database.Database.connect(Database.java:370)
        at org.pentaho.di.core.database.Database.connect(Database.java:341)
        at org.pentaho.di.core.database.Database.connect(Database.java:331)
        at org.pentaho.di.core.database.DatabaseFactory.getConnectionTestReport(DatabaseFactory.java:80)
        at org.pentaho.di.core.database.DatabaseMeta.testConnection(DatabaseMeta.java:2786)
        at org.pentaho.ui.database.event.DataHandler.testDatabaseConnection(DataHandler.java:619)
        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:498)
        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.Widget.sendEvent(Unknown Source)
        at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
        at org.eclipse.swt.widgets.Widget.notifyListeners(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:80)

    Caused by: org.pentaho.di.core.exception.KettleDatabaseException: 
    Error connecting to database: (using class org.gjt.mm.mysql.Driver)
    Communications link failure

    The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

        ... 80 more

    Hostname       :localhost
    Port           :3306
    Database name  :LAB_DW

有时我把端口改成8080，我下载了mysql连接器，但我解决不了这个问题！