Java：无安全管理器：RMI类加载器已禁用

Question

嗨，我有RMI应用程序，现在我尝试从客户端在服务器上调用一些方法。我有以下代码：

public static void main(final String[] args) {
    try {
        //Setting the security manager

        System.setSecurityManager(new RMISecurityManager());
        IndicatorsService server = (IndicatorsService) Naming
                .lookup("rmi://localhost/" + IndicatorsService.SERVICE_NAME);
        DataProvider provider = new OHLCProvider(server);
        server.registerOHLCProvider(provider);
    } catch (MalformedURLException e) {
        e.printStackTrace();
    } catch (RemoteException e) {
        e.printStackTrace();
    } catch (NotBoundException e) {
        e.printStackTrace();
    }
}

服务器已正确加载，但是在尝试致电时server.registerOHLCProvider(provider);出现以下错误：

     java.rmi.ServerException: RemoteException occurred in server thread; nested exception is: 
    java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
    java.lang.ClassNotFoundException: sk.xorty.client.providers.OHLCProvider (no security manager: RMI class loader disabled)
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:336)
    at sun.rmi.transport.Transport$1.run(Transport.java:159)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
    at sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:255)
    at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:233)
    at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:142)
    at sk.fri.statistics.service.impl.IndicatorsServiceImpl_Stub.registerOHLCProvider(Unknown Source)
    at sk.fri.statistics.service.Client.main(Client.java:61)
Caused by: java.rmi.UnmarshalException: error unmarshalling arguments; nested exception is: 
    java.lang.ClassNotFoundException: sk.xorty.client.providers.OHLCProvider (no security manager: RMI class loader disabled)
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:296)
    at sun.rmi.transport.Transport$1.run(Transport.java:159)
    at java.security.AccessController.doPrivileged(Native Method)
    at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
    at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:535)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:790)
    at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:649)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.ClassNotFoundException: sk.xorty.client.providers.OHLCProvider (no security manager: RMI class loader disabled)
    at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:375)
    at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:165)
    at java.rmi.server.RMIClassLoader$2.loadClass(RMIClassLoader.java:620)
    at java.rmi.server.RMIClassLoader.loadClass(RMIClassLoader.java:247)
    at sun.rmi.server.MarshalInputStream.resolveClass(MarshalInputStream.java:197)
    at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1574)
    at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1495)
    at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1731)
    at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
    at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
    at sun.rmi.server.UnicastRef.unmarshalValue(UnicastRef.java:306)
    at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:290)
    ... 9 more

我已将策略文件添加为VM参数，如下所示：

grant {
    permission java.security.AllPermission;
}

它一直在说关于禁用类加载的东西，所以我想问题就在那儿……谢谢！

Answer 1

远程类加载可能很棘手。

原始帖子不包含有关代码库的任何信息。客户端的安全配置可能正确，但是无法访问远程代码。客户端直接从“代码库”中加载类。服务不会通过RMI连接将它们提供给客户端。该服务仅引用类的外部源。

服务器应指定系统属性java.rmi.server.codebase。该值必须是 客户端可访问 的URL ，
可以从中加载必需的类。如果这是file:URL， 则客户端必须可以访问 文件系统 。

反之亦然：如果服务器应该能够从客户端加载类（如此处所示），则客户端必须将代码库属性设置为服务器可访问的URL。