问题描述
tomcat 7.0.39中托管的Java Web应用程序需要xvbf写入图像并将其输出到客户端.当我打开处理图像写入的servlet时，出现以下错误消息:
My java webapp hosted within a tomcat 7.0.39 needs xvbf to write into images and output them to the client. When I open the servlet which handles the image writing I get the following error message:
15.05.2013 21:24:56 org.apache.catalina.core.ApplicationContext log
SCHWERWIEGEND: StandardWrapper.Throwable
java.awt.HeadlessException
at java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:159)
at java.awt.Window.<init>(Window.java:414)
at java.awt.Frame.<init>(Frame.java:403)
at java.awt.Frame.<init>(Frame.java:368)
at serv.GroupOverview.init(GroupOverview.java:46)
at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1280)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1193)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:865)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:136)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:200)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
15.05.2013 21:24:56 org.apache.catalina.core.StandardWrapperValve invoke
SCHWERWIEGEND: Allocate exception for servlet GroupOverview
java.awt.HeadlessException
at java.awt.GraphicsEnvironment.checkHeadless(GraphicsEnvironment.java:159)
at java.awt.Window.<init>(Window.java:414)
at java.awt.Frame.<init>(Frame.java:403)
at java.awt.Frame.<init>(Frame.java:368)
at serv.GroupOverview.init(GroupOverview.java:46)
at org.apache.catalina.core.StandardWrapper.initServlet(StandardWrapper.java:1280)
at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1193)
at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:865)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:136)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:947)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.ajp.AjpProcessor.process(AjpProcessor.java:200)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:619)
引发错误的代码块如下:
The block of code where the error is thrown is the following:
public void init(ServletConfig servletConfig) throws ServletException {
super.init(servletConfig);
//
m_frame = new Frame(); // Line 46 in GroupOverview.java
m_frame.addNotify();
}
我该如何解决这个问题?
How do I solve this issue?
推荐答案
我无法理解为什么您认为需要xvfb才能在无头环境中写入图像. 您当然可以在没有xvfb的情况下进行图像(甚至是Graphics2D)操作和ImageIO.我在没有xvfb且无需创建Frame的无头环境中进行TIFF转换，颜色模型转换等.您可能需要更深入地研究.
I fail to understand why you think you need xvfb to write to images in a headless environment. You most certainly can do image (even Graphics2D) manipulation and ImageIO without xvfb. I do TIFF transformations, color model conversions, etc. in a headless environment without xvfb, and without needing to create Frame. You may want to dig a bit deeper.
但是，作为快速解决方案，请尝试设置-Djava.awt.headless = true，看看是否有帮助.
But as a quick fix, try setting -Djava.awt.headless=true and see if that helps.