耶拿+顆粒+小程序中的滑

Question

我正在嘗試將Jena庫，Pellet和一些RPG 2d庫Slick集成到一個applet中。 因此，基本上，當我在瀏覽器中運行小程序時，我收到此文件許可權錯誤（我正在使用的jar均已簽名）：

   Exception in thread "Thread-15" java.lang.ExceptionInInitializerError
    at org.mindswap.pellet.ABox.<init>(ABox.java:208)
    at org.mindswap.pellet.KnowledgeBase.clear(KnowledgeBase.java:540)
    at org.mindswap.pellet.KnowledgeBase.<init>(KnowledgeBase.java:418)
    at org.mindswap.pellet.jena.PelletInfGraph.<init>(PelletInfGraph.java:99)
    at org.mindswap.pellet.jena.PelletReasoner.bind(PelletReasoner.java:95)
    at org.mindswap.pellet.jena.PelletReasoner.bind(PelletReasoner.java:53)
    at com.hp.hpl.jena.ontology.impl.OntModelImpl.generateGraph(OntModelImpl.java:2744)
    at com.hp.hpl.jena.ontology.impl.OntModelImpl.<init>(OntModelImpl.java:139)
    at com.hp.hpl.jena.ontology.impl.OntModelImpl.<init>(OntModelImpl.java:128)
    at com.hp.hpl.jena.rdf.model.ModelFactory.createOntologyModel(ModelFactory.java:410)
    at RPGGame.GameSelectionScreen.init(GameSelectionScreen.java:170)
    at RPGGame.RPGGame.initStatesList(RPGGame.java:39)
    at org.newdawn.slick.state.StateBasedGame.init(StateBasedGame.java:164)
    at org.newdawn.slick.AppletGameContainer$Container.initApplet(AppletGameContainer.java:272)
    at org.newdawn.slick.AppletGameContainer$ContainerPanel.initGL(AppletGameContainer.java:229)
    at org.newdawn.slick.AppletGameContainer$ContainerPanel.start(AppletGameContainer.java:216)
    at org.newdawn.slick.AppletGameContainer$1.run(AppletGameContainer.java:92)
    Caused by: java.security.AccessControlException: access denied      ("java.util.PropertyPermission"     "pellet.configuration" "read")
    at java.security.AccessControlContext.checkPermission(Unknown Source)
    at java.security.AccessController.checkPermission(Unknown Source)
    at java.lang.SecurityManager.checkPermission(Unknown Source)
    at java.lang.SecurityManager.checkPropertyAccess(Unknown Source)
    at java.lang.System.getProperty(Unknown Source)
    at org.mindswap.pellet.PelletOptions.<clinit>(PelletOptions.java:805)

在此先感謝，Ioana

Answer 1

該錯誤是因為ABox試圖從PelletOptions中讀取信息，這需要加載Pellet配置。 它通常會嘗試從jar中讀取此內容，但首先，它將仔細檢查用戶在系統屬性中指定的位置是否不同於默認位置。 正是這種檢查導致了錯誤。

您可以修改PelletOptions使其始終在jar中進行檢查，而不必進行系統屬性檢查，或者您可以通過旋轉applet安全性使它正常（我不知道這樣做是否可行，以前從未使用過Applet）。