这是代码:
界面“通讯”
package itu.exercies.RMI.server;
import java.rmi.Remote;
import java.rmi.remoteexception;
public interface ICommunication extends Remote
{
public String doCommunicate(String name) throws remoteexception;
}
界面实现“CommunicationImpl”:
package itu.exercies.RMI.server;
import java.rmi.remoteexception;
import java.rmi.server.UnicastRemoteObject;
public class CommunicationImpl extends UnicastRemoteObject implements ICommunication {
/**
*
*/
private static final long serialVersionUID = 1L;
public CommunicationImpl() throws remoteexception {
super();
}
@Override
public String doCommunicate(String name) throws remoteexception {
return "Hello this is server,whats up " +name+ " ?!\n";
}
}
这是我的主要服务器类“CommunicationServer”:
package itu.exercies.RMI.server;
import java.net.MalformedURLException;
import java.rmi.Naming;
import java.rmi.remoteexception;
public class CommunicationServer {
/**
* @param args
* @throws remoteexception
* @throws MalformedURLException
*/
public static void main(String[] args) throws remoteexception,MalformedURLException {
CommunicationImpl imp = new CommunicationImpl();
Naming.rebind("CommunicationImpl",imp);
System.out.println("Server started...");
System.out.println("Object successfully registered. It is bound to the name 'CommunicationImpl'.");
}
}
这是我的客户端“CommunicationClient”:
package itu.exercies.RMI.client;
import java.net.MalformedURLException;
import java.rmi.Naming;
import java.rmi.NotBoundException;
import java.rmi.remoteexception;
import itu.exercies.RMI.server.CommunicationImpl;
public class CommunicationClient {
public static void main(String[] args) throws MalformedURLException,remoteexception,NotBoundException {
String url = new String("rmi://localhost/CommunicationImpl");
CommunicationImpl comm = (CommunicationImpl)Naming.lookup(url);
String reply = comm.doCommunicate("Wiktor");
System.out.println(reply);
}
}
现在我试图运行它:
>我使用终端导航到我的项目的bin目录
我从那里经营rmiregistry
>我从新的终端窗口运行我的CommunicationServer(它打印出的消息,使其似乎工作)
>我打开第三个终端窗口,当我尝试运行我的CommunicationClient时,它会抛出异常.
java itu.exercies.RMI.client.CommunicationClientException in thread “main” java.lang.classCastException: $Proxy0 cannot be cast to itu.exercies.RMI.server.CommunicationImpl
at itu.exercies.RMI.client.CommunicationClient.main(CommunicationClient.java:14)
到目前为止,我试图通过使用rmic创建一个“CommunicationImpl”对象的存根来修复它,但现在而不是’$Proxy0′,错误是指’CommunicationImpl_Stub’:
Exception in thread “main” java.lang.classCastException: itu.exercies.RMI.server.CommunicationImpl_Stub cannot be cast to itu.exercies.RMI.server.CommunicationImpl
at itu.exercies.RMI.client.CommunicationClient.main(CommunicationClient.java:14)
在这一点上,我不知道要查找错误.有人可以给我任何建议吗?
解决方法
CommunicationImpl comm = (CommunicationImpl) Naming.lookup(url);
同
ICommunication comm = (ICommunication) Naming.lookup(url);
CommunicationImpl是ICommunication的服务器实现.客户端既不知道也不关心实现,只有接口.