Question

我在Tomcat 6上安装的servlet应用程序中的文件系统上使用嵌入式apache derby数据库。

不幸的是，我几乎无法控制tomcat配置和其他servlet安装，我无法使用网络/服务器模式进行derby。

每当重新加载servlet时（例如出于调试目的），我都会遇到一个小问题，即旧的线程/ servlet实例和Tomcat初始化的新数据库似乎保持锁定或使用数据库。

我的应用程序尝试打开/创建数据库并且它工作正常，除非我说，我重新加载servlet。这似乎发生了，因为每当tomcat重新加载servlet并且我没有时间从正确的线程关闭数据库连接时都不会调用任何方法，当我尝试在重新加载的实例上启动新连接时，我得到：

java.sql.SQLException: Failed to start database 'C:\mydb.db' with class loader WebappClassLoader
context: /Myapp
delegate: false
repositories:
/WEB-INF/classes/
----------> Parent Classloader:
org.apache.catalina.loader.StandardClassLoader@482923
, see the next exception for details.
at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.Util.newEmbedSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.Util.seeNextException(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedConnection.bootDatabase(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedConnection.<init>(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedConnection30.<init>(Unknown Source)
at org.apache.derby.impl.jdbc.EmbedConnection40.<init>(Unknown Source)
at org.apache.derby.jdbc.Driver40.getNewEmbedConnection(Unknown Source)
at org.apache.derby.jdbc.InternalDriver.connect(Unknown Source)
at org.apache.derby.jdbc.AutoloadedDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at java.sql.DriverManager.getConnection(Unknown Source)
at myapp.Myapp.init(Myapp.java:88)
at javax.servlet.GenericServlet.init(GenericServlet.java:212)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1173)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:809)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:129)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Unknown Source)
Caused by: java.sql.SQLException: Failed to start database 'C:\mydb.db' with class loader WebappClassLoader
context: /Myapp
delegate: false
repositories:
/WEB-INF/classes/
----------> Parent Classloader:
org.apache.catalina.loader.StandardClassLoader@482923
, see the next exception for details.
at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown Source)
... 31 more
Caused by: java.sql.SQLException: Another instance of Derby may have already booted the database C:\mydb.db.
at org.apache.derby.impl.jdbc.SQLExceptionFactory.getSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.SQLExceptionFactory40.wrapArgsForTransportAcrossDRDA(Unknown Source)
at org.apache.derby.impl.jdbc.SQLExceptionFactory40.getSQLException(Unknown Source)
at org.apache.derby.impl.jdbc.Util.generateCsSQLException(Unknown Source)
... 28 more
Caused by: ERROR XSDB6: Another instance of Derby may have already booted the database C:\mydb.db.
at org.apache.derby.iapi.error.StandardException.newException(Unknown Source)
at org.apache.derby.impl.store.raw.data.BaseDataFileFactory.privGetJBMSLockOnDB(Unknown Source)
at org.apache.derby.impl.store.raw.data.BaseDataFileFactory.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at org.apache.derby.impl.store.raw.data.BaseDataFileFactory.getJBMSLockOnDB(Unknown Source)
at org.apache.derby.impl.store.raw.data.BaseDataFileFactory.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.startModule(Unknown Source)
at org.apache.derby.iapi.services.monitor.Monitor.bootServiceModule(Unknown Source)
at org.apache.derby.impl.store.raw.RawStore.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.startModule(Unknown Source)
at org.apache.derby.iapi.services.monitor.Monitor.bootServiceModule(Unknown Source)
at org.apache.derby.impl.store.access.RAMAccessManager.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.startModule(Unknown Source)
at org.apache.derby.iapi.services.monitor.Monitor.bootServiceModule(Unknown Source)
at org.apache.derby.impl.db.BasicDatabase.bootStore(Unknown Source)
at org.apache.derby.impl.db.BasicDatabase.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.boot(Unknown Source)
at org.apache.derby.impl.services.monitor.TopService.bootModule(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.bootService(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.startProviderService(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.findProviderAndStartService(Unknown Source)
at org.apache.derby.impl.services.monitor.BaseMonitor.startPersistentService(Unknown Source)
at org.apache.derby.iapi.services.monitor.Monitor.startPersistentService(Unknown Source)
... 28 more

我还尝试在尝试创建新连接之前删除db.lck文件，但此文件被tomcat锁定且无法删除。还使用以下命令关闭所有derby系统：DriverManager.getConnection（“jdbc：derby :; shutdown = true”）;

导致正确的异常，但是当应用程序创建新连接时，存在多次访问的相同错误。

有什么方法可以避免这种情况吗？

Answer 1

我的建议是您需要修改context.xml文件的内容。

<Context>
    <Resource name="jdbc/testDB" auth="Container" type="javax.sql.DataSource"
            maxActive="20" maxIdle="10" username="classiccars" password="classiccars"
            driverClassName="org.apache.derby.jdbc.EmbeddedDriver"
            url="jdbc:derby:C:\Users\Nakshatra\.myeclipse\derby\myeclipse"/>
</Context>


   Note:you need to log on as an Administrator if you use Windows 7 OS.
   http://www.mytechguide.org/106/how-to-log-on-as-administrator-in-windows-7/

Answer 2

在更改Tomcat 8.0的上下文路径后，我遇到了同样的问题。什么真正帮助了我 - Eclipse重新启动。

Apache Derby - 嵌入式模式 - 重新加载servlet时无法启动数据库

2 个答案: