Question

我为RMI编写了一个简单的Hello world程序。当客户端在控制台中时，它运行良好。我尝试使用Swing应用程序作为我的客户端，它甚至可以正常工作。

但是当我使用applet作为客户端时，会抛出以下异常：

Exception in thread "AWT-EventQueue-1" java.security.AccessControlException: access denied (java.net.SocketPermission 127.0.0.1:1099 connect,resolve)
        at java.security.AccessControlContext.checkPermission(AccessControlContext.java:323)
        at java.security.AccessController.checkPermission(AccessController.java:546)
        at java.lang.SecurityManager.checkPermission(SecurityManager.java:532)
        at java.lang.SecurityManager.checkConnect(SecurityManager.java:1034)
        at java.net.Socket.connect(Socket.java:524)
        at java.net.Socket.connect(Socket.java:478)
        at java.net.Socket.<init>(Socket.java:375)
        at java.net.Socket.<init>(Socket.java:189)
        at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(RMIDirectSocketFactory.java:22)
        at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(RMIMasterSocketFactory.java:128)
        at sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:595)
        at sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:198)
        at sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:184)
        at sun.rmi.server.UnicastRef.newCall(UnicastRef.java:322)
        at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
        at java.rmi.Naming.lookup(Naming.java:84)
        at Client.<init>(Client.java:23)
        at MyApplet.submitActionPerformed(MyApplet.java:179)
        at MyApplet.access$300(MyApplet.java:22)
        at MyApplet$4.actionPerformed(MyApplet.java:84)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
        at java.awt.Component.processMouseEvent(Component.java:6263)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
        at java.awt.Component.processEvent(Component.java:6028)
        at java.awt.Container.processEvent(Container.java:2041)
        at java.awt.Component.dispatchEventImpl(Component.java:4630)
        at java.awt.Container.dispatchEventImpl(Container.java:2099)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4574)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4238)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4168)
        at java.awt.Container.dispatchEventImpl(Container.java:2085)
        at java.awt.Component.dispatchEvent(Component.java:4460)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

为什么会如此，我该怎么做才能使我的计划有效？

Answer 1

查看this link是否可以为您提供解决此问题所需的信息：

所有小程序和任何应用程序必须使用安全管理器调用被授予明确的许可分别访问本地系统资源从读取访问目录和它的子目录所在的程序被调用。 Java平台提供允许各种级别的权限访问不同类型的本地信息。

有关不同权限和策略文件的详细信息，请参阅上面的链接。

Answer 2

对于applet，网络访问的简单安全规则是：它有权连接它来自的远程服务器，但没有别的。

因此，您必须在同一服务器上运行RMI注册表，该服务器也是applet所在的Web服务器。

为什么在从applet使用RMI时会出现AccessControlException？

2 个答案: