отправка объектов на/из клиента/сервера

Question

Я ищу решение для моей ошибки, возникающей при попытке отправить объект со стороны сервера на клиентскую.

Объект в форме как экземпляр класса будет создан путем нажатия на JButton. Также будет создан клиентский класс, который переносит объект на сервер. Ошибок не будет. Но когда дело доходит до отправки нового объекта обратно клиенту, будет выбрано ClassCastException.

ActionListener Класс

class ActionHandler implements ActionListener { 
    String buttonPressed; 
    List<String> parameterList = new ArrayList<String>(); 

    public void actionPerformed(ActionEvent event) { 
     if(event.getSource() == executeNameSearch) { 
     buttonPressed = "NameSearch"; 
     parameterList = new ArrayList<String>(); 
     parameterList.add(pizzaNameSearch.getText()); 
     ObjectToServer object = new ObjectToServer(buttonPressed, parameterList); 

     // build connection to server 
     Client client = new Client(); 
     client.connectToServer(object); 
     } 
     else if(event.getSource() == executeNameSearch) { 
     buttonPressed = "IDSuche"; 
     parameterList = new ArrayList<String>(); 
     parameterList.add(pizzaIDSearch.getText()); 
     ObjectToServer object = new ObjectToServer(buttonPressed, parameterList); 

     Client client = new Client(); 
     client.connectToServer(object); 
     } 
     // some more actionPerformed cases.. 
    } 
} 

класс Client

public class Client { 
    public void connectToServer(ObjectToServer object) { 
     Socket server = null; 
     try { 
     server = new Socket("localhost", 3141); 
     ObjectOutputStream oos = new ObjectOutputStream(server.getOutputStream()); 
     ObjectInputStream ois = new ObjectInputStream(server.getInputStream()); 

     // sending object to server 
     oos.writeObject(object); 
     oos.flush(); 

     // receiving object from server 
     try { 
      // ERROR BY TRYING TO CAST HERE 
      ObjectToClient objectIn = (ObjectToClient) ois.readObject(); 
     } catch (ClassNotFoundException e) { 
      e.printStackTrace(); 
     } 

     oos.close(); 
     ois.close(); 
     } catch(UnknownHostException e) { 
     e.printStackTrace(); 
     } catch(IOException e) { 
     e.printStackTrace(); 
     } finally { 
     if(server!=null) { 
      try { 
       server.close(); 
      } catch(IOException e) { 
       System.out.println(e); 
      } 
     } 
     } 
    } 
} 

Class Server

public class Server { 
    static PizzaManager manager = new PizzaManager(); 
    private static void handleConnection(Socket client) throws IOException { 
     ObjectInputStream ois = new ObjectInputStream(client.getInputStream()); 
     ObjectOutputStream oos = new ObjectOutputStream(client.getOutputStream()); 

     ObjectToServer objectIn; 
     try { 
      objectIn = (ObjectToServer) ois.readObject(); 
      String buttonPressed = objectIn.getButtonPressed(); 

      if(buttonPressed.equals("NamenSuche")) { 
       String searchedPizzaName = objectIn.getParameterList().get(0); 
       manager.namenSuche(searchedPizzaName); 

       ObjectToClient objectOut = new ObjectToClient(); 
       objectOut.setResults(manager.getResults()); 
       oos.writeObject(objectIn); 
      } 
      // some more cases.. 
     } catch (ClassNotFoundException e) { 
      e.printStackTrace(); 
     } 

     ois.close(); 
     oos.close(); 
    } 

    public static void main(String[] args) throws IOException { 
     ServerSocket server = new ServerSocket(3141); 
     while(true) { 
     Socket client = null; 
     try { 
      client = server.accept(); 
      handleConnection(client); 
     } 
     catch(IOException e) { 
      e.printStackTrace(); 
     } 
     finally { 
      if(client!=null) { 
       try { 
        client.close(); 
       } 
       catch(IOException e) { 
       } 
      } 
     } 
     } 
    } 
} 

StackTrace

Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: 
transfer.ObjectToServer cannot be cast to server.ObjectToClient 
at client.Client.connectToServer(Client.java:34) 
at gui.Pizzasuche$ActionHandler.actionPerformed(Pizzasuche.java:362) 
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source) 
at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source) 
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source) 
at javax.swing.DefaultButtonModel.setPressed(Unknown Source) 
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source) 
at java.awt.Component.processMouseEvent(Unknown Source) 
at javax.swing.JComponent.processMouseEvent(Unknown Source) 
at java.awt.Component.processEvent(Unknown Source) 
at java.awt.Container.processEvent(Unknown Source) 
at java.awt.Component.dispatchEventImpl(Unknown Source) 
at java.awt.Container.dispatchEventImpl(Unknown Source) 
at java.awt.Component.dispatchEvent(Unknown Source) 
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source) 
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source) 
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source) 
at java.awt.Container.dispatchEventImpl(Unknown Source) 
at java.awt.Window.dispatchEventImpl(Unknown Source) 
at java.awt.Component.dispatchEvent(Unknown Source) 
at java.awt.EventQueue.dispatchEventImpl(Unknown Source) 
at java.awt.EventQueue.access$200(Unknown Source) 
at java.awt.EventQueue$3.run(Unknown Source) 
at java.awt.EventQueue$3.run(Unknown Source) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) 
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) 
at java.awt.EventQueue$4.run(Unknown Source) 
at java.awt.EventQueue$4.run(Unknown Source) 
at java.security.AccessController.doPrivileged(Native Method) 
at java.security.ProtectionDomain$1.doIntersectionPrivilege(Unknown Source) 
at java.awt.EventQueue.dispatchEvent(Unknown Source) 
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source) 
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source) 
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source) 
at java.awt.EventDispatchThread.pumpEvents(Unknown Source) 
at java.awt.EventDispatchThread.pumpEvents(Unknown Source) 
at java.awt.EventDispatchThread.run(Unknown Source) 

Спасибо за вашу помощь!

Answer 1

Я думаю, что в вашем классе Server вы пытаетесь отправить обратно неправильный объект. Должно быть не так:

oos.writeObject(objectOut); 

?

Прямо сейчас вы отправляете обратно objectIn который является ObjectToServer экземпляра (или, по меньшей мере, отливают в виде так), тогда как вы пытаетесь бросить его как ObjectToClient стороны клиента, следовательно, ClassCastException.

Фиксированный класс сервера:

public class Server { 
    static PizzaManager manager = new PizzaManager(); 
    private static void handleConnection(Socket client) throws IOException { 
     ObjectInputStream ois = new ObjectInputStream(client.getInputStream()); 
     ObjectOutputStream oos = new ObjectOutputStream(client.getOutputStream()); 

     ObjectToServer objectIn; 
     try { 
      objectIn = (ObjectToServer) ois.readObject(); 
      String buttonPressed = objectIn.getButtonPressed(); 

      if(buttonPressed.equals("NamenSuche")) { 
       String searchedPizzaName = objectIn.getParameterList().get(0); 
       manager.namenSuche(searchedPizzaName); 

       ObjectToClient objectOut = new ObjectToClient(); 
       objectOut.setResults(manager.getResults()); 
       oos.writeObject(objectOut); // instead of objectIn 
      } 
      // some more cases.. 
     } catch (ClassNotFoundException e) { 
      e.printStackTrace(); 
     } 

     ois.close(); 
     oos.close(); 
    } 

    public static void main(String[] args) throws IOException { 
     ServerSocket server = new ServerSocket(3141); 
     while(true) { 
     Socket client = null; 
     try { 
      client = server.accept(); 
      handleConnection(client); 
     } 
     catch(IOException e) { 
      e.printStackTrace(); 
     } 
     finally { 
      if(client!=null) { 
       try { 
        client.close(); 
       } 
       catch(IOException e) { 
       } 
      } 
     } 
     } 
    } 
}