速度初始化失败

Question

我使用velocity作为Java代码生成器，我正在运行一个Eclipse应用程序，它有多个插件，不同的插件调用velocity模块进行代码生成。

每当我运行一个特定的插件时，不管我运行多少次，它都可以单独工作，现在如果我试图运行另一个插件，它会抛出速度异常（我在下面提供了堆栈跟踪），我将再次重启eclipse，其他插件也可以工作。

结论：当一个插件在某个插件已经执行后运行时，Velocity初始化失败

    velocityEngine = new VelocityEngine();
    velocityEngine.setProperty(RuntimeConstants.RESOURCE_LOADER, LOCATION);
    velocityEngine.setProperty(RESOURCE_LOADER,ClasspathResourceLoader.class.getName());
    try {
        velocityEngine.init();
    } catch (Exception e) {
        LOG.error("Failed to load velocity templates e={}", e); 
    }

    velocityEngine = new VelocityEngine();
    velocityEngine.setProperty(RuntimeConstants.RESOURCE_LOADER, "class,file");
    velocityEngine.setProperty(RuntimeConstants.RUNTIME_LOG_LOGSYSTEM_CLASS, "org.apache.velocity.runtime.log.Log4JLogChute");
    velocityEngine.setProperty("runtime.log.logsystem.log4j.logger", "VELLOGGER");
    velocityEngine.setProperty("class.resource.loader.class", "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
    velocityEngine.setProperty("runtime.log.logsystem.class", "org.apache.velocity.runtime.log.NullLogSystem");
    /*  
    velocityEngine.setProperty(RuntimeConstants.RESOURCE_LOADER, LOCATION);
    velocityEngine.setProperty(RESOURCE_LOADER,ClasspathResourceLoader.class.getName());
     */
    try{
        LOG.debug("Velocity Initialisation In AbstractFactory");
        velocityEngine.init();
        LOG.debug("Velocity Initialisation Done!!!");
    }catch(Exception e){
        LOG.error("Error Occured In Initialising Velocity Engine {}",e); 
    }

但它还是失败了

template = velocityEngine.getTemplate(COMMAND_TEMPLATE_LOCATION.concat(command).concat(TEMPLATE_EXTENSION));

使用异常堆栈跟踪：

org.apache.velocity.exception.VelocityException: Error initializing log: Failed to initialize an instance of org.apache.velocity.runtime.log.NullLogSystem with the current runtime configuration.
at org.apache.velocity.runtime.RuntimeInstance.initializeLog(RuntimeInstance.java:875)
at org.apache.velocity.runtime.RuntimeInstance.init(RuntimeInstance.java:262)
at org.apache.velocity.app.VelocityEngine.init(VelocityEngine.java:93)
at com.yodlee.dap.cortex.generation.engine.AbstractTemplateFactory.<init>(AbstractTemplateFactory.java:68)
at com.yodlee.dap.cortex.generation.engine.GenericTemplateFactory.<init>(GenericTemplateFactory.java:26)
at com.yodlee.dap.cortex.generation.generator.CodeGenerator.generateCode(CodeGenerator.java:52)
at com.yodlee.dap.cortex.codegenerator.processor.CodeGenProcessor.process(CodeGenProcessor.java:75)
at com.yodlee.dap.cortex.codegenerator.handler.CortexHandler.handle(CortexHandler.java:80)
at com.yodlee.dap.cortex.codegenerator.handler.CortexHandler.handle(CortexHandler.java:48)
at com.yodlee.dap.cortex.codegenerator.generate.CodeGenHandler.generate(CodeGenHandler.java:23)
at com.yodlee.eclipse.json.template.generator.code.TemplateGenerator.writeJavaFile(TemplateGenerator.java:228)
at com.yodlee.eclipse.json.template.generator.code.TemplateGenerator.findNewStates(TemplateGenerator.java:291)
at com.yodlee.eclipse.json.template.generator.code.TemplateGenerator.codeParser(TemplateGenerator.java:137)
at com.yodlee.eclipse.json.site.flow.CodeGenerator.generate(CodeGenerator.java:24)
at com.yodlee.eclipse.json.editor.JsonEditor.addBrowserContent(JsonEditor.java:310)
at com.yodlee.eclipse.json.editor.JsonEditor.setJsonInput(JsonEditor.java:450)
at com.yodlee.eclipse.json.editor.JsonReconcileStrategy$1.run(JsonReconcileStrategy.java:66)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:182)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4211)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3827)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$4.run(PartRenderingEngine.java:1121)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1022)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:150)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:693)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:610)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:148)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:138)
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:388)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243)
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:483)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:673)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:610)
at org.eclipse.equinox.launcher.Main.run(Main.java:1519)
at org.eclipse.equinox.launcher.Main.main(Main.java:1492)
Caused by: org.apache.velocity.exception.VelocityException: Failed to initialize an instance of org.apache.velocity.runtime.log.NullLogSystem with the current runtime configuration.
at org.apache.velocity.runtime.log.LogManager.createLogChute(LogManager.java:220)
at org.apache.velocity.runtime.log.LogManager.updateLog(LogManager.java:269)
at org.apache.velocity.runtime.RuntimeInstance.initializeLog(RuntimeInstance.java:871)
... 42 common frames omitted
Caused by: org.apache.velocity.exception.VelocityException: The specified logger class org.apache.velocity.runtime.log.NullLogSystem does not implement the org.apache.velocity.runtime.log.LogChute interface.
at org.apache.velocity.runtime.log.LogManager.createLogChute(LogManager.java:181)
... 44 common frames omitted
  12:32:52.177 [main] DEBUG com.yodlee.dap.cortex.generation.engine.GenericTemplateFactory - Start getGenericTemplate For= GenericClass
12:32:52.180 [main] ERROR com.yodlee.dap.cortex.generation.engine.GenericTemplateFactory - Error Occured In Velocity initialisation Module  {}
org.apache.velocity.exception.VelocityException: Error initializing log: Failed to initialize an instance of org.apache.velocity.runtime.log.CommonsLogLogChute with the current runtime configuration.
at org.apache.velocity.runtime.RuntimeInstance.initializeLog(RuntimeInstance.java:875)
at org.apache.velocity.runtime.RuntimeInstance.init(RuntimeInstance.java:262)
at org.apache.velocity.app.VelocityEngine.init(VelocityEngine.java:93)
at com.yodlee.dap.cortex.generation.engine.GenericTemplateFactory.getGenericTemplate(GenericTemplateFactory.java:43)
at com.yodlee.dap.cortex.generation.generator.CodeGenerator.generateCode(CodeGenerator.java:52)
at com.yodlee.dap.cortex.codegenerator.processor.CodeGenProcessor.process(CodeGenProcessor.java:75)
at com.yodlee.dap.cortex.codegenerator.handler.CortexHandler.handle(CortexHandler.java:80)
at com.yodlee.dap.cortex.codegenerator.handler.CortexHandler.handle(CortexHandler.java:48)
at com.yodlee.dap.cortex.codegenerator.generate.CodeGenHandler.generate(CodeGenHandler.java:23)
at com.yodlee.eclipse.json.template.generator.code.TemplateGenerator.writeJavaFile(TemplateGenerator.java:228)
at com.yodlee.eclipse.json.template.generator.code.TemplateGenerator.findNewStates(TemplateGenerator.java:291)
at com.yodlee.eclipse.json.template.generator.code.TemplateGenerator.codeParser(TemplateGenerator.java:137)
at com.yodlee.eclipse.json.site.flow.CodeGenerator.generate(CodeGenerator.java:24)
at com.yodlee.eclipse.json.editor.JsonEditor.addBrowserContent(JsonEditor.java:310)
at com.yodlee.eclipse.json.editor.JsonEditor.setJsonInput(JsonEditor.java:450)
at com.yodlee.eclipse.json.editor.JsonReconcileStrategy$1.run(JsonReconcileStrategy.java:66)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:182)
at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4211)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3827)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$4.run(PartRenderingEngine.java:1121)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1022)
at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:150)
at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:693)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:610)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:148)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:138)
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:388)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243)
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:483)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:673)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:610)
at org.eclipse.equinox.launcher.Main.run(Main.java:1519)
at org.eclipse.equinox.launcher.Main.main(Main.java:1492)
Caused by: org.apache.velocity.exception.VelocityException: Failed to initialize an instance of org.apache.velocity.runtime.log.CommonsLogLogChute with the current runtime configuration.
at org.apache.velocity.runtime.log.LogManager.createLogChute(LogManager.java:220)
at org.apache.velocity.runtime.log.LogManager.updateLog(LogManager.java:269)
at org.apache.velocity.runtime.RuntimeInstance.initializeLog(RuntimeInstance.java:871)
... 41 common frames omitted
Caused by: org.apache.velocity.exception.VelocityException: The specified logger class org.apache.velocity.runtime.log.CommonsLogLogChute does not implement the org.apache.velocity.runtime.log.LogChute interface.
at org.apache.velocity.runtime.log.LogManager.createLogChute(LogManager.java:181)
... 43 common frames omitted

Answer 1

后来我找到了问题的真正根源。当一个插件初始化速度时，另一个插件无法重新初始化它，因为运行时环境是相同的。另外，这两个模块都是作为单独的模块出现的，因此它无法访问它，因为范围问题，因此速度初始化失败。

我们实现的解决方案是，我们把两个插件都放在一个模块下，因此从一个模块初始化的类可以被其他模块访问。