Connection.close（）之后數據庫仍在使用中

Question

當我連接到數據庫（其位置由JFileChooser提供）時，我檢查數據庫是否已過時，並在必要時嘗試刪除它並替換它。 我得到的錯誤如下：

java.io.IOException: Unable to delete file: C:\Users\User\Documents\POS-Data\Tables\seg0\cd1.dat
at org.apache.commons.io.FileUtils.forceDelete(FileUtils.java:2279)
at org.apache.commons.io.FileUtils.cleanDirectory(FileUtils.java:1653)
at org.apache.commons.io.FileUtils.deleteDirectory(FileUtils.java:1535)
at org.apache.commons.io.FileUtils.forceDelete(FileUtils.java:2270)
at org.apache.commons.io.FileUtils.cleanDirectory(FileUtils.java:1653)
at org.apache.commons.io.FileUtils.deleteDirectory(FileUtils.java:1535)
at Admin.SendReceiveData.SendData(SendReceiveData.java:226)
at Admin.SendReceiveData.SendAllBActionPerformed(SendReceiveData.java:183)
at Admin.SendReceiveData.access$100(SendReceiveData.java:13)
at Admin.SendReceiveData$3.actionPerformed(SendReceiveData.java:151)
at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2346)
at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
at java.awt.Component.processMouseEvent(Component.java:6525)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3322)
at java.awt.Component.processEvent(Component.java:6290)
at java.awt.Container.processEvent(Container.java:2234)
at java.awt.Component.dispatchEventImpl(Component.java:4881)
at java.awt.Container.dispatchEventImpl(Container.java:2292)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4898)
at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4533)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4462)
at java.awt.Container.dispatchEventImpl(Container.java:2278)
at java.awt.Window.dispatchEventImpl(Window.java:2739)
at java.awt.Component.dispatchEvent(Component.java:4703)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:751)
at java.awt.EventQueue.access$500(EventQueue.java:97)
at java.awt.EventQueue$3.run(EventQueue.java:702)
at java.awt.EventQueue$3.run(EventQueue.java:696)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:86)
at java.awt.EventQueue$4.run(EventQueue.java:724)
at java.awt.EventQueue$4.run(EventQueue.java:722)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:75)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:721)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

我使用以下網址：

String URL = "jdbc:derby:" + DestinationFile.getAbsolutePath() + "\\Tables;create=true;user=root;password=root";

請注意，我始終使用Connection.close（），但在關閉程序之前，數據庫似乎處於打開狀態。 這使我無法更新數據庫，關於如何完全釋放數據庫資源的任何建議？

（System.gc無法正常工作）

Answer 1

斷開與數據庫的連接並不意味着datatbe將關閉並釋放其資源-如文件句柄。 您將需要先關閉數據庫。

此外，如果您正在應用程序中嵌入Derby，則意味着數據庫與應用程序在同一JVM中運行。 在這種情況下，通過使用API​​關機會為您提供幫助。

Answer 2

我找到了解決我問題的方法：

DriverManager.getConnection(URL+";shutdown=true");

將關閉數據庫！