Java RMI 远程服务器接口上的 ClassNotFound 异常

Question

这是我的服务器主代码

public static void main(String Args[]){
      try {
        masterDAO = MasterDAO.getInstance();
    } catch (MasterException e) {
        e.printStackTrace();
        LOGGER.log(Level.SEVERE,e.getMessage() + "MASTER SHUTDOWN");
        System.exit(1);
    }
    final int REGISTRYPORT = 1499;
    String registryHost = "localhost";
    String serviceName = "MasterService";
    try {
        String completeName = "//" + registryHost + ":" + REGISTRYPORT + "/" + serviceName;
        System.out.println(completeName);
        MasterInterface master = (MasterInterface) new Master();
        registry = LocateRegistry.createRegistry(REGISTRYPORT);
        registry.rebind(completeName, master);
        System.out.println("Master Bound ");
    }
    catch (Exception e) {
        System.err.println("Master exception: ");
        e.printStackTrace();
    }
}

这是客户端的方法：

public FileLocation getFileLocation(String fileName, String operation){

    final int REGISTRYPORT = 1499;
    String serviceName = "MasterService";
    String completeName = "//" + "localhost" + ":" + REGISTRYPORT + "/" + serviceName;
    try {
        System.out.println(completeName);
        Registry masterRegistry = LocateRegistry.getRegistry(1499);
        System.out.println(globalInformation.getHost() + " "+REGISTRYPORT);
        MasterInterface master = (MasterInterface) masterRegistry.lookup(completeName);
        //System.out.println("Get File Location - Result: " + fileLocation.isResult() + " - Port: "+ fileLocation.getFilePositions());
        return master.checkFile(fileName,operation);
    }
    catch (NotBoundException | IOException e) {
        e.printStackTrace();
    }  catch (FileNotFoundException e) {

        System.out.println("ERROR 404 FILE NOT FOUND");
    } catch (MasterException e) {

        System.out.println("ERROR 500 INTERNAL SERVER ERROR");
    }
    return  null;
}

我遇到了这个异常

java.rmi.UnmarshalException: error unmarshalling return; nested exception is: 
java.lang.ClassNotFoundException: MasterInterface (no security manager: RMI class loader disabled)
at sun.rmi.registry.RegistryImpl_Stub.lookup(RegistryImpl_Stub.java:127)
at com.sdcc_project.cloudlet.controller.CloudLetController.getFileLocation(CloudLetController.java:125)
at com.sdcc_project.cloudlet.controller.CloudLetController.writeToMaster(CloudLetController.java:149)
at com.sdcc_project.cloudlet.CloudletApplication.run(CloudletApplication.java:126)
Caused by: java.lang.ClassNotFoundException: MasterInterface (no security manager: RMI class loader disabled)
at sun.rmi.server.LoaderHandler.loadProxyClass(LoaderHandler.java:556)
at java.rmi.server.RMIClassLoader.loadProxyClass(RMIClassLoader.java:646)
at java.rmi.server.RMIClassLoader.loadProxyClass(RMIClassLoader.java:311)
at sun.rmi.server.MarshalInputStream.resolveProxyClass(MarshalInputStream.java:265)
at java.io.ObjectInputStream.readProxyDesc(ObjectInputStream.java:1800)
at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1748)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:2042)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1573)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:431)
at sun.rmi.registry.RegistryImpl_Stub.lookup(RegistryImpl_Stub.java:123)
... 3 more

服务器在本地执行启动它的 main ，客户端像在 tomcat 服务器上的 spring 应用程序一样执行。在 spring 上部署之前，我曾经像普通应用程序一样运行客户端并且一切正常，所以我认为问题可能出在 tomcat 类路径上？这是项目的包 -->

Answer 1

服务器端应用程序与客户端应用程序的共享类和接口（例如 MasterInterface）具有不同的包名称可能会导致此问题。

检查这两个项目并确保它在两个项目中具有相同的命名。尝试实现相同的层次结构，例如：

package com.xx.yy.server_intarface;  // same in server and client application

public interface MasterInterface { ...

这解决了问题，但不仅 "package" 值必须相同，所有导入路径也必须相同。

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