java - JDBC替换: SQLNonTransientConnectionException

Question

在我的java项目中，我从utf8切换到utf8mb4。我删除了数据库，然后使用 utf8mb4 创建了一个新数据库。我还使用 https://mathiasbynens.be/notes/mysql-utf8mb4 的输入更改了 mysql-Configuration: my.ini现在的更改如下所示:

[client]
default-character-set = utf8mb4
[mysql]
default-character-set = utf8mb4
[mysqld]
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci

我检查过:

SHOW VARIABLES WHERE Variable_name LIKE 'character\_set\_%' OR Variable_name LIKE 'collation%';

character_set_filesystem, binary
character_set_client, utf8
character_set_connection, utf8
character_set_results, utf8
character_set_system, utf8
collation_connection, utf8_general_ci
character_set_database, utf8mb4
character_set_server, utf8mb4
collation_database, utf8mb4_unicode_ci
collation_server, utf8mb4_unicode_ci

我尝试添加 - 但 mysql 现在没有启动 - 所以我删除了它:

character_set_client=utf8mb4
character_set_connection=utf8mb4
character_set_results=utf8mb4

现在我重新启动了数据库。

然后我将新的驱动程序加载到项目中，并用最新的驱动程序替换旧的驱动程序。 (-> 现在:mysql-connector-java-6.0.5-bin)我还将我的java代码更改为(因为驱动程序错误告诉我这样做):Class.forName("com.mysql.cj.jdbc.Driver");

后来我改变了:

    String databaseUrl = "jdbc:mysql://localhost:3306/myDB?useSSL=false&autoReconnect=true&characterEncoding=utf8mb4";

(because: SQLException: java.sql.SQLException: Unsupported character encoding 'utf8mb4'
Exception in thread "JavaFX Application Thread" java.lang.ExceptionInInitializerError)

至:

    String databaseUrl = "jdbc:mysql://localhost:3306/myDB?useSSL=false&autoReconnect=true";

使用新方法会抛出:

    SQLException: java.sql.SQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
Exception in thread "JavaFX Application Thread" java.lang.ExceptionInInitializerError
    at auxiliary.InputCreater.saveFile(InputCreater.java:100)
    at auxiliary.InputCreater.searchnewfiles(InputCreater.java:54)
    at gui.EingabefensterController$3.handle(EingabefensterController.java:70)
    at gui.EingabefensterController$3.handle(EingabefensterController.java:1)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:86)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:49)
    at javafx.event.Event.fireEvent(Event.java:198)
    at javafx.scene.control.MenuItem.fire(MenuItem.java:462)
    at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.doSelect(ContextMenuContent.java:1405)
    at com.sun.javafx.scene.control.skin.ContextMenuContent$MenuItemContainer.lambda$createChildren$343(ContextMenuContent.java:1358)
    at com.sun.javafx.event.CompositeEventHandler$NormalEventHandlerRecord.handleBubblingEvent(CompositeEventHandler.java:218)
    at com.sun.javafx.event.CompositeEventHandler.dispatchBubblingEvent(CompositeEventHandler.java:80)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:238)
    at com.sun.javafx.event.EventHandlerManager.dispatchBubblingEvent(EventHandlerManager.java:191)
    at com.sun.javafx.event.CompositeEventDispatcher.dispatchBubblingEvent(CompositeEventDispatcher.java:59)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:58)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.BasicEventDispatcher.dispatchEvent(BasicEventDispatcher.java:56)
    at com.sun.javafx.event.EventDispatchChainImpl.dispatchEvent(EventDispatchChainImpl.java:114)
    at com.sun.javafx.event.EventUtil.fireEventImpl(EventUtil.java:74)
    at com.sun.javafx.event.EventUtil.fireEvent(EventUtil.java:54)
    at javafx.event.Event.fireEvent(Event.java:198)
    at javafx.scene.Scene$MouseHandler.process(Scene.java:3757)
    at javafx.scene.Scene$MouseHandler.access$1500(Scene.java:3485)
    at javafx.scene.Scene.impl_processMouseEvent(Scene.java:1762)
    at javafx.scene.Scene$ScenePeerListener.mouseEvent(Scene.java:2494)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:380)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler$MouseEventNotification.run(GlassViewEventHandler.java:294)
    at java.security.AccessController.doPrivileged(Native Method)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.lambda$handleMouseEvent$354(GlassViewEventHandler.java:416)
    at com.sun.javafx.tk.quantum.QuantumToolkit.runWithoutRenderLock(QuantumToolkit.java:389)
    at com.sun.javafx.tk.quantum.GlassViewEventHandler.handleMouseEvent(GlassViewEventHandler.java:415)
    at com.sun.glass.ui.View.handleMouseEvent(View.java:555)
    at com.sun.glass.ui.View.notifyMouse(View.java:937)
    at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
    at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.NullPointerException
    at java.util.concurrent.ArrayBlockingQueue.checkNotNull(ArrayBlockingQueue.java:150)
    at java.util.concurrent.ArrayBlockingQueue.offer(ArrayBlockingQueue.java:325)
    at java.util.AbstractQueue.add(AbstractQueue.java:95)
    at java.util.concurrent.ArrayBlockingQueue.add(ArrayBlockingQueue.java:312)
    at mysql.ConnectionPoolManager.initializeConnectionPool(ConnectionPoolManager.java:49)
    at mysql.ConnectionPoolManager.initialize(ConnectionPoolManager.java:43)
    at mysql.ConnectionPoolManager.<init>(ConnectionPoolManager.java:28)
    at mysql.CrawlerUpdate.<clinit>(CrawlerUpdate.java:18)
    ... 46 more

为什么没有连接？在我进行所有这些更改之前，一切都运行良好。

Answer 1

问题出在缺失

&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=UTC

我通过改变网址发现了它。