我正在尝试使用带有 Eclipse 的应用程序引擎运行示例程序。我根据本网站中的说明安装谷歌插件： https ://developers.google.com/appengine/docs/java/gettingstarted/installing
按照教程。但由于某种原因，我的应用程序不会运行。我收到以下错误：
14/12/2012 14:13:41 com.google.apphosting.utils.jetty.JettyLogger info
INFO: Logging to JettyLogger(null) via com.google.apphosting.utils.jetty.JettyLogger
14/12/2012 14:13:41 com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
INFO: Successfully processed C:\Users\rona\workspace\Guestbook\war\WEB-INF/appengine-web.xml
14/12/2012 14:13:41 com.google.apphosting.utils.config.AppEngineWebXmlReader readAppEngineWebXml
SEVERE: Received exception processing C:\Users\rona\workspace\Guestbook\war\WEB-INF/appengine-web.xml
com.google.apphosting.utils.config.AppEngineConfigException: appengine-web.xml does not contain a <threadsafe> element.
See http://code.google.com/appengine/docs/java/config/appconfig.html#Using_Concurrent_Requests for more information.
You probably want to enable concurrent requests.
at com.google.apphosting.utils.config.AppEngineWebXmlReader.readAppEngineWebXml(AppEngineWebXmlReader.java:79)
at com.google.apphosting.utils.config.EarHelper.readWebModule(EarHelper.java:130)
at com.google.appengine.tools.development.AbstractContainerService.loadAppEngineWebXml(AbstractContainerService.java:334)
at com.google.appengine.tools.development.JettyContainerService.initContext(JettyContainerService.java:160)
at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:227)
at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:157)
at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:333)
at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:269)
at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:245)
com.google.apphosting.utils.config.AppEngineConfigException: Invalid appengine-web.xml(C:\Users\rona\workspace\Guestbook\war\WEB-INF/appengine-web.xml) - appengine-web.xml does not contain a <threadsafe> element.
See http://code.google.com/appengine/docs/java/config/appconfig.html#Using_Concurrent_Requests for more information.
You probably want to enable concurrent requests.
at com.google.apphosting.utils.config.EarHelper.readWebModule(EarHelper.java:132)
at com.google.appengine.tools.development.AbstractContainerService.loadAppEngineWebXml(AbstractContainerService.java:334)
at com.google.appengine.tools.development.JettyContainerService.initContext(JettyContainerService.java:160)
at com.google.appengine.tools.development.AbstractContainerService.startup(AbstractContainerService.java:227)
at com.google.appengine.tools.development.DevAppServerImpl.start(DevAppServerImpl.java:157)
at com.google.appengine.tools.development.DevAppServerMain$StartAction.apply(DevAppServerMain.java:333)
at com.google.appengine.tools.util.Parser$ParseResult.applyArgs(Parser.java:48)
at com.google.appengine.tools.development.DevAppServerMain.<init>(DevAppServerMain.java:269)
at com.google.appengine.tools.development.DevAppServerMain.main(DevAppServerMain.java:245)
该应用程序的代码是从谷歌开发人员复制的完全相同。我知道该程序在另一台计算机上运行。我安装中的某些东西不起作用。