osgi中使用ucanaccess时出错

Question

我读过问题UcanAccess intro，但无法让驱动程序在OSGi / RCP应用程序中工作。我认为这是一个类加载器问题，但不知道如何解决它。

相关的代码片段，它在第二行失败。MDB存在，使用UcanAccess的非OSGi应用程序可以成功地打开它。

Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");
con = DriverManager.getConnection("jdbc:ucanaccess://" + FILENAME);

我得到以下例外：

**4302 INFO  org.eclipse.ecf.osgi.services.remoteserviceadmin - [S:{org.osgi.framework.hooks.service.EventListenerHook}={service.id=274, service.bundleid=86, service.scope=singleton}] ServiceEvent REGISTERED
net.ucanaccess.jdbc.UcanaccessSQLException: user lacks privilege or object not found java.lang.ClassNotFoundException: net.ucanaccess.converters.Functions cannot be found by org.hsqldb.hsqldb_2.3.1 net.ucanaccess.converters.Functions in statement [CREATE FUNCTION SLN(par0 DOUBLE,par1 DOUBLE,par2 DOUBLE) RETURNS DOUBLE  LANGUAGE JAVA DETERMINISTIC NO SQL  EXTERNAL NAME 'CLASSPATH:net.ucanaccess.converters.Functions.sln']
    at net.ucanaccess.jdbc.UcanaccessDriver.connect(UcanaccessDriver.java:247)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:270)
    at com.easa.motordb.load.HornerLoad.execute(HornerLoad.java:26)
    at org.eclipse.ui.internal.handlers.HandlerProxy.execute(HandlerProxy.java:294)
    at org.eclipse.ui.internal.handlers.E4HandlerProxy.execute(E4HandlerProxy.java:90)
    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.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:55)
    at org.eclipse.e4.core.internal.di.InjectorImpl.invokeUsingClass(InjectorImpl.java:247)
    at org.eclipse.e4.core.internal.di.InjectorImpl.invoke(InjectorImpl.java:229)
    at org.eclipse.e4.core.contexts.ContextInjectionFactory.invoke(ContextInjectionFactory.java:132)
    at org.eclipse.e4.core.commands.internal.HandlerServiceHandler.execute(HandlerServiceHandler.java:149)
    at org.eclipse.core.commands.Command.executeWithChecks(Command.java:499)
    at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:508)
    at org.eclipse.e4.core.commands.internal.HandlerServiceImpl.executeHandler(HandlerServiceImpl.java:210)
    at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.executeItem(HandledContributionItem.java:825)
    at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.handleWidgetSelection(HandledContributionItem.java:701)
    at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem.access$6(HandledContributionItem.java:685)
    at org.eclipse.e4.ui.workbench.renderers.swt.HandledContributionItem$4.handleEvent(HandledContributionItem.java:613)
    at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
    at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4353)
    at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1061)
    at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4172)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3761)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1151)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1032)
    at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:148)
    at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:636)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:579)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:150)
    at com.easa.acmotor.base.Application.start(Application.java:24)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:380)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:235)
    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.eclipse.equinox.launcher.Main.invokeFramework(Main.java:648)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:603)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1465)
    at org.eclipse.equinox.launcher.Main.main(Main.java:1438)
Caused by: java.sql.SQLSyntaxErrorException: user lacks privilege or object not found java.lang.ClassNotFoundException: net.ucanaccess.converters.Functions cannot be found by org.hsqldb.hsqldb_2.3.1 net.ucanaccess.converters.Functions in statement [CREATE FUNCTION SLN(par0 DOUBLE,par1 DOUBLE,par2 DOUBLE) RETURNS DOUBLE  LANGUAGE JAVA DETERMINISTIC NO SQL  EXTERNAL NAME 'CLASSPATH:net.ucanaccess.converters.Functions.sln']
    at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
    at org.hsqldb.jdbc.JDBCUtil.sqlException(Unknown Source)
    at org.hsqldb.jdbc.JDBCStatement.fetchResult(Unknown Source)
    at org.hsqldb.jdbc.JDBCStatement.executeUpdate(Unknown Source)
    at net.ucanaccess.converters.LoadJet.exec(LoadJet.java:1258)
    at net.ucanaccess.converters.LoadJet.access$0(LoadJet.java:1253)
    at net.ucanaccess.converters.LoadJet$FunctionsLoader.createFunctions(LoadJet.java:156)
    at net.ucanaccess.converters.LoadJet$FunctionsLoader.addFunctions(LoadJet.java:151)
    at net.ucanaccess.converters.LoadJet$FunctionsLoader.loadMappedFunctions(LoadJet.java:178)
    at net.ucanaccess.converters.LoadJet$FunctionsLoader.access$2(LoadJet.java:177)
    at net.ucanaccess.converters.LoadJet.loadDB(LoadJet.java:1310)
    at net.ucanaccess.jdbc.UcanaccessDriver.connect(UcanaccessDriver.java:236)
    ... 48 more
Caused by: org.hsqldb.HsqlException: user lacks privilege or object not found java.lang.ClassNotFoundException: net.ucanaccess.converters.Functions cannot be found by org.hsqldb.hsqldb_2.3.1 net.ucanaccess.converters.Functions
    at org.hsqldb.error.Error.error(Unknown Source)
    at org.hsqldb.Routine.getMethods(Unknown Source)
    at org.hsqldb.Routine.getMethod(Unknown Source)
    at org.hsqldb.Routine.resolveReferences(Unknown Source)
    at org.hsqldb.Routine.resolve(Unknown Source)
    at org.hsqldb.StatementSchema.getResult(Unknown Source)
    at org.hsqldb.StatementSchema.execute(Unknown Source)
    at org.hsqldb.Session.executeCompiledStatement(Unknown Source)
    at org.hsqldb.Session.executeDirectStatement(Unknown Source)
    at org.hsqldb.Session.execute(Unknown Source)
    ... 58 more
Caused by: java.lang.ClassNotFoundException: net.ucanaccess.converters.Functions cannot be found by org.hsqldb.hsqldb_2.3.1
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:432)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at java.lang.Class.forName0(Native Method)
    at java.lang.Class.forName(Class.java:264)
    ... 67 more

我已采取下列步骤：

1. 从ucanaccess创建插件/包
2. Require bundle: org.hsqldb.hsqldb;bundle-version="2.3.1“
3. 让它成为注册伙伴(：已注册)
4. 让我的包知道它(Eclipse-RegisterBuddy: ucanaccess)
5. 确保所有包都自动启动(ucanaccess、hsql和my bundle)

Answer 1

我最初只在新包中包含了ucanaccess.jar文件，并将其他jar文件放在目标平台/插件列表中。

解决方案是使用所有UcanAccess所需的jar文件(ucanaccess-2.0.9.4.jar、Common-lang-2.6.jar、commons 1.1.1.jar、hsqldb.jar、jackcess-2.0.8.jar)创建新的包。

Answer 2

您忽略了在getConnection中放置数据库用户名和密码的空“”。试试下面的代码：

con = DriverManager.getConnection("jdbc:ucanaccess://" + FILENAME, "", "");

Answer 3

你的问题现在可能已经解决了，但对于那些能用另一条小贴士来说:放下电话。

Class.forName("net.ucanaccess.jdbc.UcanaccessDriver");

对我来说效果很好。我真正使用JDK 1.8和Jackcess 2.08年