Java RMI-在运行时获取ClassNotFoundException

我花了将近五个小时试图解决这个问题，但没有结果。我已经创建了一个使用RMI的应用程序。它编译得很好，但我无法让它运行。 我所有的类文件都在C:\Users\Benji\Desktop\ass2\build中（是“赋值”的缩写；没有脏东西）。所有源文件都位于C:\Users\Benji\Desktop\ass2\src中。 我将所有内容都放在一个包中，以使内容更易于理解（并更改了源代码中的导入语句以反映这一点）

我已经在C:\Users\Benji\Desktop\ass2\中放置了一个批处理文件。其包含执行语句：

java -classpath ./build -Djava.rmi.server.codebase=file:/C:/Users/Benji/Desktop/ass2/build -Djava.security.policy=broker.policy BrokerReception Broker 16890

（程序需要两个参数“Broker”和“16890”）

文件broker.policy也位于C:\Users\Benji\Desktop\ass2\中。其内容包括:

grant
{
    permission java.security.AllPermission;
};

（是的，我意识到这不是一个好的安全策略。我将在稍后对此进行研究）

实际上有三个主要类，一个用于客户机，一个用于代理（客户机的中介）和一个服务器。我正在试着启动经纪人。Broker接口的代码如下所示：

import java.io.FileNotFoundException;
import java.rmi.Remote;
import java.rmi.RemoteException;
import java.util.ArrayList;

public interface Broker extends Remote
{
    public boolean getAvailability(int startDate, int endDate) throws FileNotFoundException, RemoteException;

    public ArrayList<CityInfo> getCities() throws FileNotFoundException, RemoteException;

    public ArrayList<HotelInfo> getCityHotels(int cityNumber) throws FileNotFoundException, RemoteException;

    public int getHotelRoomRate(int hotelNumber) throws FileNotFoundException, RemoteException;

    public boolean makeBooking(String firstName, String lastName, String contact, String creditCardNo) throws FileNotFoundException, RemoteException;
}

上面代码中的“Directory”是一个访问数据库的类

我不知道我还需要提供什么信息。谁能告诉我我做错了什么？ 顺便说一句，我回去在上做了Oracle的RMI教程，看看是否能找出问题所在。本教程没有提到代码库或安全策略，但提供了编译和执行的所有代码和精确说明。我严格遵守这些指示，但即使这样也不起作用

堆栈跟踪：

java.rmi.ServerException: RemoteException occurred in server thread; nested exce
ption is:
        java.rmi.UnmarshalException: error unmarshalling arguments; nested excep
tion is:
        java.lang.ClassNotFoundException: Broker
        at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:396
)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:250)
        at sun.rmi.transport.Transport$1.run(Transport.java:159)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:5
35)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTranspor
t.java:790)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport
.java:649)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.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(Stream
RemoteCall.java:255)
        at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:
233)
        at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:359)
        at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
        at BrokerReception.main(BrokerReception.java:32)
Caused by: java.rmi.UnmarshalException: error unmarshalling arguments; nested ex
ception is:
        java.lang.ClassNotFoundException: Broker
        at sun.rmi.registry.RegistryImpl_Skel.dispatch(Unknown Source)
        at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:386
)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:250)
        at sun.rmi.transport.Transport$1.run(Transport.java:159)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:5
35)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTranspor
t.java:790)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport
.java:649)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.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: Broker
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:247)
        at sun.rmi.server.LoaderHandler.loadProxyInterfaces(LoaderHandler.java:7
11)
        at sun.rmi.server.LoaderHandler.loadProxyClass(LoaderHandler.java:655)
        at sun.rmi.server.LoaderHandler.loadProxyClass(LoaderHandler.java:592)
        at java.rmi.server.RMIClassLoader$2.loadProxyClass(RMIClassLoader.java:6
28)
        at java.rmi.server.RMIClassLoader.loadProxyClass(RMIClassLoader.java:294
)
        at sun.rmi.server.MarshalInputStream.resolveProxyClass(MarshalInputStrea
m.java:238)
        at java.io.ObjectInputStream.readProxyDesc(ObjectInputStream.java:1530)
        at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1492)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1
731)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
        ... 12 more

---

如果您将注册表作为第二个进程运行，它需要访问远程类。最简单的方法是在启动注册表时向命令行添加适当的classpath参数

---

如果您试图使用远程类加载，我相信您需要在应用程序中设置rmi安全管理器，无论是在命令行还是在main方法中。（就个人而言，分发类通常适用于99%的情况，并且更容易获得正确的结果）。

stacktrace会很有帮助-找不到哪个类。在Try..catch处理程序中尝试从

cnfe

捕获真实的类名-可能不是数据库驱动程序类。。。。。。还有当你得到它时你在做什么。有3种不同的情况。对不起，忘记了堆栈跟踪。我已经离开几天了：/。找不到的类似乎是代理接口。还有，最奇怪的是：我已经做了第二个教程，可以在。

import java.io.FileNotFoundException;
import java.rmi.RemoteException;
import java.rmi.registry.LocateRegistry;
import java.rmi.registry.Registry;
import java.rmi.server.UnicastRemoteObject;
import java.sql.SQLException;

public class BrokerReception
{
    public static void main(String[] args)
    {
        System.out.println("Args are:");
        for(String arg : args)
        {
            System.out.println(arg);
        }
        System.out.println();

        try
        {
            BrokerDatabase directory = new BrokerDatabase();
            directory.connect(args[0]);

            int activeHotelNumber = Integer.parseInt(args[1]);
            if(directory.checkActiveHotelExists(activeHotelNumber))
            {
                BrokerClientLiaison liaison = new BrokerClientLiaison(directory, activeHotelNumber);
                Broker liaisonStub = (Broker) UnicastRemoteObject.exportObject(liaison, 0);
                Registry registry = LocateRegistry.getRegistry();
                registry.rebind(Protocol.BROKER_INTERFACE_NAME, liaisonStub);
            }
            else
            {
                throw new FileNotFoundException();
            }
        }
        catch(ArrayIndexOutOfBoundsException aioobe)
        {
            System.err.println("Args required:");
            System.err.println("1. Name of database file");
            System.err.println("2. Number of active hotel");
            System.exit(1);
        }
        catch(ClassNotFoundException cnfe)
        {
            System.err.println("Couldn't load database driver");
            System.exit(2);
        }
        catch(SQLException sqle)
        {
            System.err.println("Couldn't establish connection to database");
            System.err.println("Check that the database has been properly registerd,");
            System.err.println("and that you provided the correct name");
            System.exit(3);
        }
        catch(NumberFormatException nfe)
        {
            System.err.println("Second argument must be an integer");
            System.exit(4);
        }
        catch(FileNotFoundException fnfe)
        {
            System.err.println("The database contains no entries with that hotel number");
            System.exit(5);
        }
        catch(RemoteException re)
        {
            System.err.println("Unable to bind as " + Protocol.BROKER_INTERFACE_NAME);
            re.printStackTrace();
            System.exit(6);
        }
    }
}

java.rmi.ServerException: RemoteException occurred in server thread; nested exce
ption is:
        java.rmi.UnmarshalException: error unmarshalling arguments; nested excep
tion is:
        java.lang.ClassNotFoundException: Broker
        at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:396
)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:250)
        at sun.rmi.transport.Transport$1.run(Transport.java:159)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:5
35)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTranspor
t.java:790)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport
.java:649)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.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(Stream
RemoteCall.java:255)
        at sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:
233)
        at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:359)
        at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)
        at BrokerReception.main(BrokerReception.java:32)
Caused by: java.rmi.UnmarshalException: error unmarshalling arguments; nested ex
ception is:
        java.lang.ClassNotFoundException: Broker
        at sun.rmi.registry.RegistryImpl_Skel.dispatch(Unknown Source)
        at sun.rmi.server.UnicastServerRef.oldDispatch(UnicastServerRef.java:386
)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:250)
        at sun.rmi.transport.Transport$1.run(Transport.java:159)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:155)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:5
35)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTranspor
t.java:790)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport
.java:649)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExec
utor.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: Broker
        at java.net.URLClassLoader$1.run(URLClassLoader.java:202)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(URLClassLoader.java:190)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:248)
        at java.lang.Class.forName0(Native Method)
        at java.lang.Class.forName(Class.java:247)
        at sun.rmi.server.LoaderHandler.loadProxyInterfaces(LoaderHandler.java:7
11)
        at sun.rmi.server.LoaderHandler.loadProxyClass(LoaderHandler.java:655)
        at sun.rmi.server.LoaderHandler.loadProxyClass(LoaderHandler.java:592)
        at java.rmi.server.RMIClassLoader$2.loadProxyClass(RMIClassLoader.java:6
28)
        at java.rmi.server.RMIClassLoader.loadProxyClass(RMIClassLoader.java:294
)
        at sun.rmi.server.MarshalInputStream.resolveProxyClass(MarshalInputStrea
m.java:238)
        at java.io.ObjectInputStream.readProxyDesc(ObjectInputStream.java:1530)
        at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1492)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1
731)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
        ... 12 more