代码在 JavaSE 中工作，但在 Wildfly 中崩溃并出现 NullPointerException
Code works in JavaSE, but crashes in Wildfly with NullPointerException
我正在使用 gephi-toolkit (0.9.1) 生成图表，编写了一个 javaSE 应用程序，测试了它等等。
在将此代码复制粘贴到我的 EJB 时（尝试了所有三种类型）代码开始生成：
java.lang.RuntimeException: java.lang.NullPointerException
关于将图表导出为 SVG（还有 PNG）。
我明确检查了我的对象 - 它们不为空。因此，gephi-toolkit 内部的某些东西与 JavaSE 兼容，但与 JavaEE 不兼容。
任何提示或建议如何查找和解决问题？
我尝试导出到文件 (File.createTempFile())
然后流式传输 - StringWriter 和 OutputStream。
三个都失败了。
ExportController ec = Lookup.getDefault().lookup(ExportController.class);
SVGExporter exp = (SVGExporter) ec.getExporter("svg");
StringWriter sw = new StringWriter();
exp.setWriter(sw);
exp.setWorkspace(workspace);
System.out.println(" exec: " + exp.execute());
ec、exp 和 sw 不为空，但我在 exp.execute()
上得到 NPE
更新：
java.lang.RuntimeException: java.lang.NullPointerException
at org.gephi.io.exporter.preview.SVGExporter.execute(SVGExporter.java:113)
at model.GraphBuilder.generateGraph(GraphBuilder.java:155)
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:498)
at org.jboss.as.ee.component.ManagedReferenceMethodInterceptor.processInvocation(ManagedReferenceMethodInterceptor.java:52)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.doMethodInterception(Jsr299BindingsInterceptor.java:82)
at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.processInvocation(Jsr299BindingsInterceptor.java:93)
at org.jboss.as.ee.component.interceptors.UserInterceptorFactory.processInvocation(UserInterceptorFactory.java:63)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.invocationmetrics.ExecutionTimeInterceptor.processInvocation(ExecutionTimeInterceptor.java:43)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.jpa.interceptor.SBInvocationInterceptor.processInvocation(SBInvocationInterceptor.java:47)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437)
at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:64)
at org.jboss.as.weld.ejb.EjbRequestScopeActivationInterceptor.processInvocation(EjbRequestScopeActivationInterceptor.java:83)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ee.concurrent.ConcurrentContextInterceptor.processInvocation(ConcurrentContextInterceptor.java:45)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InitialInterceptor.processInvocation(InitialInterceptor.java:21)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
at org.jboss.as.ee.component.interceptors.ComponentDispatcherInterceptor.processInvocation(ComponentDispatcherInterceptor.java:52)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.pool.PooledInstanceInterceptor.processInvocation(PooledInstanceInterceptor.java:51)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:275)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:327)
at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:239)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.invocationmetrics.WaitTimeInterceptor.processInvocation(WaitTimeInterceptor.java:47)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.security.SecurityContextInterceptor.processInvocation(SecurityContextInterceptor.java:100)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.deployment.processors.StartupAwaitInterceptor.processInvocation(StartupAwaitInterceptor.java:22)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory.processInvocation(ShutDownInterceptorFactory.java:64)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:67)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.as.ejb3.component.interceptors.AdditionalSetupInterceptor.processInvocation(AdditionalSetupInterceptor.java:54)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.ContextClassLoaderInterceptor.processInvocation(ContextClassLoaderInterceptor.java:64)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356)
at org.wildfly.security.manager.WildFlySecurityManager.doChecked(WildFlySecurityManager.java:636)
at org.jboss.invocation.AccessCheckingInterceptor.processInvocation(AccessCheckingInterceptor.java:61)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356)
at org.jboss.invocation.PrivilegedWithCombinerInterceptor.processInvocation(PrivilegedWithCombinerInterceptor.java:80)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:198)
at org.jboss.as.ee.component.ViewDescription.processInvocation(ViewDescription.java:185)
at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340)
at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61)
at org.jboss.as.ee.component.ProxyInvocationHandler.invoke(ProxyInvocationHandler.java:73)
at model.GraphBuilder$$$view20.generateGraph(Unknown Source)
at beans.Controller.submit3(Controller.java:193)
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:498)
at com.sun.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:181)
at com.sun.el.parser.AstValue.invoke(AstValue.java:289)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304)
at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40)
at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40)
at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50)
at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105)
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
at javax.faces.component.UICommand.broadcast(UICommand.java:315)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790)
at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282)
at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292)
at io.undertow.servlet.handlers.ServletInitialHandler.access0(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler.call(ServletInitialHandler.java:138)
at io.undertow.servlet.handlers.ServletInitialHandler.call(ServletInitialHandler.java:135)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction.call(ServletRequestContextThreadSetupAction.java:48)
at io.undertow.servlet.core.ContextClassLoaderSetupAction.call(ContextClassLoaderSetupAction.java:43)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272)
at io.undertow.servlet.handlers.ServletInitialHandler.access[=19=]0(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler.handleRequest(ServletInitialHandler.java:104)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202)
at io.undertow.server.HttpServerExchange.run(HttpServerExchange.java:805)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:748)
ERROR [stderr] (default task-11) Caused by: java.lang.NullPointerException
at org.gephi.preview.plugin.renderers.NodeLabelRenderer.renderSVG(NodeLabelRenderer.java:277)
at org.gephi.preview.plugin.renderers.NodeLabelRenderer.render(NodeLabelRenderer.java:198)
at org.gephi.preview.PreviewControllerImpl.render(PreviewControllerImpl.java:251)
at org.gephi.preview.PreviewControllerImpl.render(PreviewControllerImpl.java:208)
at org.gephi.io.exporter.preview.SVGExporter.execute(SVGExporter.java:95)
执行摘要：代码在桌面上工作但在服务器上失败，因为服务器处于无头模式，并且代码使用了一些功能（此处getBBox()) 在 Batik 中 需要 GUI.
简单 Java SE 程序中的代码 运行 与服务器环境中的相同代码 运行 之间的主要区别在于，后者最有可能 无头.
Gephi delegates to Batik for SVG generation，反过来 Batik 使用 java.awt 来处理一些渲染细节，并且渲染（可能）是边界框计算所必需的（getBBox()），不幸的是，gephi 依赖于上。
Batik 源代码中用于 crash on headless environments. Now it mostly works. See this example 的旧版本 Batik：
/**
* Returns the active screen resolution. If Batik is run in a headless environment, this
* method will return the default "96" unlike {@link Toolkit#getScreenResolution()} which
* will throw a {@link HeadlessException}.
* @return the screen resolution in dpi
*/
public static int getScreenResolution() {
if (GraphicsEnvironment.isHeadless()) {
return 96;
} else {
return Toolkit.getDefaultToolkit().getScreenResolution();
}
}
但在尝试计算边界框时似乎仍然有限。
因此，如果可能的话，一个值得尝试的建议（根据您的情况，它可能非常简单，也可能非常复杂）：在非无头环境中启动您的服务器 .
Wildfly（和大多数服务器）在命令行中默认 runs with -Djava.awt.headless=true。应该可以通过编辑 standalone.conf.
来改变它
为此，您需要一个显示器。例如在 Linux 上，给它一个有效的 $DISPLAY 来使用，它将指向一个虚拟显示器，比如 VNC 服务器，或者更好的是使用虚拟帧缓冲区，它是一个 'fake' X 服务器（避免在服务器上使用 X-windows，CentOS 的软件包是 xorg-x11-server-xvfb，Debian 的是 xvfb）。
也许这不是一个令人满意的生产解决方案，但如果可行，它至少是一个很好的线索，可以帮助确定下一步要看的地方：如何让 getBBox() 在无头环境中工作，或者让 gephi 工作而不需要 getBBox().
我正在使用 gephi-toolkit (0.9.1) 生成图表，编写了一个 javaSE 应用程序，测试了它等等。
在将此代码复制粘贴到我的 EJB 时（尝试了所有三种类型）代码开始生成：
java.lang.RuntimeException: java.lang.NullPointerException
关于将图表导出为 SVG（还有 PNG）。
我明确检查了我的对象 - 它们不为空。因此，gephi-toolkit 内部的某些东西与 JavaSE 兼容，但与 JavaEE 不兼容。
任何提示或建议如何查找和解决问题？
我尝试导出到文件 (File.createTempFile())
然后流式传输 - StringWriter 和 OutputStream。
三个都失败了。
ExportController ec = Lookup.getDefault().lookup(ExportController.class);
SVGExporter exp = (SVGExporter) ec.getExporter("svg");
StringWriter sw = new StringWriter();
exp.setWriter(sw);
exp.setWorkspace(workspace);
System.out.println(" exec: " + exp.execute());
ec、exp 和 sw 不为空，但我在 exp.execute()
更新：
java.lang.RuntimeException: java.lang.NullPointerException at org.gephi.io.exporter.preview.SVGExporter.execute(SVGExporter.java:113) at model.GraphBuilder.generateGraph(GraphBuilder.java:155) 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:498) at org.jboss.as.ee.component.ManagedReferenceMethodInterceptor.processInvocation(ManagedReferenceMethodInterceptor.java:52) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437) at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.doMethodInterception(Jsr299BindingsInterceptor.java:82) at org.jboss.as.weld.ejb.Jsr299BindingsInterceptor.processInvocation(Jsr299BindingsInterceptor.java:93) at org.jboss.as.ee.component.interceptors.UserInterceptorFactory.processInvocation(UserInterceptorFactory.java:63) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.component.invocationmetrics.ExecutionTimeInterceptor.processInvocation(ExecutionTimeInterceptor.java:43) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.jpa.interceptor.SBInvocationInterceptor.processInvocation(SBInvocationInterceptor.java:47) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.invocation.InterceptorContext$Invocation.proceed(InterceptorContext.java:437) at org.jboss.weld.ejb.AbstractEJBRequestScopeActivationInterceptor.aroundInvoke(AbstractEJBRequestScopeActivationInterceptor.java:64) at org.jboss.as.weld.ejb.EjbRequestScopeActivationInterceptor.processInvocation(EjbRequestScopeActivationInterceptor.java:83) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ee.concurrent.ConcurrentContextInterceptor.processInvocation(ConcurrentContextInterceptor.java:45) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.invocation.InitialInterceptor.processInvocation(InitialInterceptor.java:21) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) at org.jboss.as.ee.component.interceptors.ComponentDispatcherInterceptor.processInvocation(ComponentDispatcherInterceptor.java:52) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.component.pool.PooledInstanceInterceptor.processInvocation(PooledInstanceInterceptor.java:51) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.tx.CMTTxInterceptor.invokeInOurTx(CMTTxInterceptor.java:275) at org.jboss.as.ejb3.tx.CMTTxInterceptor.required(CMTTxInterceptor.java:327) at org.jboss.as.ejb3.tx.CMTTxInterceptor.processInvocation(CMTTxInterceptor.java:239) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.component.interceptors.CurrentInvocationContextInterceptor.processInvocation(CurrentInvocationContextInterceptor.java:41) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.component.invocationmetrics.WaitTimeInterceptor.processInvocation(WaitTimeInterceptor.java:47) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.security.SecurityContextInterceptor.processInvocation(SecurityContextInterceptor.java:100) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.deployment.processors.StartupAwaitInterceptor.processInvocation(StartupAwaitInterceptor.java:22) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.component.interceptors.ShutDownInterceptorFactory.processInvocation(ShutDownInterceptorFactory.java:64) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:67) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ee.component.NamespaceContextInterceptor.processInvocation(NamespaceContextInterceptor.java:50) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.as.ejb3.component.interceptors.AdditionalSetupInterceptor.processInvocation(AdditionalSetupInterceptor.java:54) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.invocation.ContextClassLoaderInterceptor.processInvocation(ContextClassLoaderInterceptor.java:64) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356) at org.wildfly.security.manager.WildFlySecurityManager.doChecked(WildFlySecurityManager.java:636) at org.jboss.invocation.AccessCheckingInterceptor.processInvocation(AccessCheckingInterceptor.java:61) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.invocation.InterceptorContext.run(InterceptorContext.java:356) at org.jboss.invocation.PrivilegedWithCombinerInterceptor.processInvocation(PrivilegedWithCombinerInterceptor.java:80) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) at org.jboss.as.ee.component.ViewService$View.invoke(ViewService.java:198) at org.jboss.as.ee.component.ViewDescription.processInvocation(ViewDescription.java:185) at org.jboss.invocation.InterceptorContext.proceed(InterceptorContext.java:340) at org.jboss.invocation.ChainedInterceptor.processInvocation(ChainedInterceptor.java:61) at org.jboss.as.ee.component.ProxyInvocationHandler.invoke(ProxyInvocationHandler.java:73) at model.GraphBuilder$$$view20.generateGraph(Unknown Source) at beans.Controller.submit3(Controller.java:193) 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:498) at com.sun.el.util.ReflectionUtil.invokeMethod(ReflectionUtil.java:181) at com.sun.el.parser.AstValue.invoke(AstValue.java:289) at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:304) at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40) at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50) at org.jboss.weld.util.el.ForwardingMethodExpression.invoke(ForwardingMethodExpression.java:40) at org.jboss.weld.el.WeldMethodExpression.invoke(WeldMethodExpression.java:50) at com.sun.faces.facelets.el.TagMethodExpression.invoke(TagMethodExpression.java:105) at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:87) at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102) at javax.faces.component.UICommand.broadcast(UICommand.java:315) at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:790) at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1282) at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81) at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:198) at javax.faces.webapp.FacesServlet.service(FacesServlet.java:658) at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:85) at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62) at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36) at org.wildfly.extension.undertow.security.SecurityContextAssociationHandler.handleRequest(SecurityContextAssociationHandler.java:78) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131) at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46) at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64) at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60) at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77) at io.undertow.security.handlers.NotificationReceiverHandler.handleRequest(NotificationReceiverHandler.java:50) at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at org.wildfly.extension.undertow.security.jacc.JACCContextIdHandler.handleRequest(JACCContextIdHandler.java:61) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43) at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292) at io.undertow.servlet.handlers.ServletInitialHandler.access0(ServletInitialHandler.java:81) at io.undertow.servlet.handlers.ServletInitialHandler.call(ServletInitialHandler.java:138) at io.undertow.servlet.handlers.ServletInitialHandler.call(ServletInitialHandler.java:135) at io.undertow.servlet.core.ServletRequestContextThreadSetupAction.call(ServletRequestContextThreadSetupAction.java:48) at io.undertow.servlet.core.ContextClassLoaderSetupAction.call(ContextClassLoaderSetupAction.java:43) at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44) at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44) at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44) at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44) at io.undertow.servlet.api.LegacyThreadSetupActionWrapper.call(LegacyThreadSetupActionWrapper.java:44) at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272) at io.undertow.servlet.handlers.ServletInitialHandler.access[=19=]0(ServletInitialHandler.java:81) at io.undertow.servlet.handlers.ServletInitialHandler.handleRequest(ServletInitialHandler.java:104) at io.undertow.server.Connectors.executeRootHandler(Connectors.java:202) at io.undertow.server.HttpServerExchange.run(HttpServerExchange.java:805) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:748) ERROR [stderr] (default task-11) Caused by: java.lang.NullPointerException at org.gephi.preview.plugin.renderers.NodeLabelRenderer.renderSVG(NodeLabelRenderer.java:277) at org.gephi.preview.plugin.renderers.NodeLabelRenderer.render(NodeLabelRenderer.java:198) at org.gephi.preview.PreviewControllerImpl.render(PreviewControllerImpl.java:251) at org.gephi.preview.PreviewControllerImpl.render(PreviewControllerImpl.java:208) at org.gephi.io.exporter.preview.SVGExporter.execute(SVGExporter.java:95)
执行摘要：代码在桌面上工作但在服务器上失败，因为服务器处于无头模式，并且代码使用了一些功能（此处getBBox()) 在 Batik 中 需要 GUI.
简单 Java SE 程序中的代码 运行 与服务器环境中的相同代码 运行 之间的主要区别在于，后者最有可能 无头.
Gephi delegates to Batik for SVG generation，反过来 Batik 使用 java.awt 来处理一些渲染细节，并且渲染（可能）是边界框计算所必需的（getBBox()），不幸的是，gephi 依赖于上。
Batik 源代码中用于 crash on headless environments. Now it mostly works. See this example 的旧版本 Batik：
/**
* Returns the active screen resolution. If Batik is run in a headless environment, this
* method will return the default "96" unlike {@link Toolkit#getScreenResolution()} which
* will throw a {@link HeadlessException}.
* @return the screen resolution in dpi
*/
public static int getScreenResolution() {
if (GraphicsEnvironment.isHeadless()) {
return 96;
} else {
return Toolkit.getDefaultToolkit().getScreenResolution();
}
}
但在尝试计算边界框时似乎仍然有限。
因此，如果可能的话，一个值得尝试的建议（根据您的情况，它可能非常简单，也可能非常复杂）：在非无头环境中启动您的服务器 .
Wildfly（和大多数服务器）在命令行中默认 runs with -Djava.awt.headless=true。应该可以通过编辑 standalone.conf.
为此，您需要一个显示器。例如在 Linux 上，给它一个有效的 $DISPLAY 来使用，它将指向一个虚拟显示器，比如 VNC 服务器，或者更好的是使用虚拟帧缓冲区，它是一个 'fake' X 服务器（避免在服务器上使用 X-windows，CentOS 的软件包是 xorg-x11-server-xvfb，Debian 的是 xvfb）。
也许这不是一个令人满意的生产解决方案，但如果可行，它至少是一个很好的线索，可以帮助确定下一步要看的地方：如何让 getBBox() 在无头环境中工作，或者让 gephi 工作而不需要 getBBox().