14

我有 2 个 java netbeans 项目，一个是服务器，另一个是客户端。我有一个我创建的 Message 类，我想在服务器上完成修改后将其传递给服务器并以另一种方式返回给客户端。我在两个项目中都包含了 Message 类。我使用ObjectOutputStreamandObjectInputStream来传递对象。服务器和客户端之间的连接正常，对象通过但在服务器上，当我从ObjectInputStreamusingreadObject()方法读取对象时，我键入将其转换为Message类。但是在服务器上抛出了ClassNotFoundException 。它找不到 Message 类。我该如何解决这个问题？

客户端代码：

public void startClient() {
    try {
        // Create the socket
        Socket clientSocket = new Socket(HOST, PORT);
        // Create the input & output streams to the server
        ObjectOutputStream outToServer = new ObjectOutputStream(clientSocket.getOutputStream());
        ObjectInputStream inFromServer = new ObjectInputStream(clientSocket.getInputStream());

        // Read modify
        // TODO here

        /* Create The Message Object to send */
        LinkedList<Message> msgList = new LinkedList<>();
        Message msg = new Message();
        msg.setMessage("Kasun");
        msg.setIndex(1);
        msg.setAverage(5.5f);
        msgList.push(msg);

        /* Send the Message Object to the server */
        outToServer.writeObject(msgList);            

        /* Retrive the Message Object from server */
        LinkedList<Message> inFromServerList = new LinkedList<>();
        Message msgFrmServer = null;
        inFromServerList = (LinkedList<Message>)inFromServer.readObject();
        msgFrmServer = inFromServerList.pop();

        /* Print out the recived Message */
        System.out.println("Message: " + msgFrmServer.getMessage());
        System.out.println("Index: " + msgFrmServer.getIndex());
        System.out.println("Average: " + msgFrmServer.getAverage());


        clientSocket.close();

    } catch (Exception e) {
        System.err.println("Client Error: " + e.getMessage());
        System.err.println("Localized: " + e.getLocalizedMessage());
        System.err.println("Stack Trace: " + e.getStackTrace());
    }
}

服务器代码

public void startServer() {

    try {
        ServerSocket welcomeSocket = new ServerSocket(PORT);

        while (true) {    
            // Create the Client Socket
            Socket clientSocket = welcomeSocket.accept();
            System.out.println("Socket Extablished...");
            // Create input and output streams to client
            ObjectOutputStream outToClient = new ObjectOutputStream(clientSocket.getOutputStream());
            ObjectInputStream inFromClient = new ObjectInputStream(clientSocket.getInputStream());

            // Read modify
            // TODO here

            /* Create Message object and retrive information */
            LinkedList<Message> inList = new LinkedList<>();
            Message inMsg = null;
            inList = (LinkedList<Message>)inFromClient.readObject();
            inMsg = inList.pop();

            /* Modify the message object */
            inMsg.setMessage(inMsg.getMessage().toUpperCase());
            inMsg.setIndex(5);
            inMsg.setAverage(10.5f);

            /* Send the modified Message object back */
            outToClient.writeObject(inMsg);        

        }

    } catch (Exception e) {
        System.err.println("Server Error: " + e.getMessage());
        System.err.println("Localized: " + e.getLocalizedMessage());
        System.err.println("Stack Trace: " + e.getStackTrace());
        System.err.println("To String: " + e.toString());
    }
}

在“服务器”引发的异常

java.lang.ClassNotFoundException: rusl.online.examination.system.client.utility.Message

我必须使用java RMI吗？有没有不使用 RMI 的解决方案？

4

2 回答 2

7

确保服务器端的 Message 是rusl.online.examination.system.client.utility.Message. 似乎并非如此。

于 2013-10-07T05:20:52.520 回答
1

如果您通过套接字发送类的对象。为了在另一端复制对象，您必须投射对象。为此，您将需要两端的类定义。

确保您也为服务器程序正确导入了Message用于创建消息的相同类。

于 2013-10-07T05:17:45.850 回答