java - 无法从服务器传输 "get"流

Question

我正在尝试制作一个简单的客户端-服务器应用程序，但是当我执行代码时，我收到一个异常，即客户端无法获取套接字的输入流。请查看我的代码并尝试提供帮助。谢谢:)

P.S:抱歉代码困惑。将其作为两个不同的应用程序执行。

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.InetAddress;
import java.net.Socket;


public class SimpleClient //implements Runnable 
{
   private ObjectOutputStream output; // output stream to server
   private ObjectInputStream input; // input stream from server
   private String message = ""; // message from server
   private String chatServer="localhost"; // host server for this application
   private Socket client; // socket to communicate with server

   public void runClient() 
   {
      try // connect to server, get streams, process connection
      {
         connectToServer(); // create a Socket to make connection
         getStreams(); // get the input and output streams
         processConnection(); // process connection
      } // end try
      catch(IOException ioe)
      {
          ioe.printStackTrace();
      }
      finally 
      {
        // closeConnection(); // close connection
      } // end finally
   }

    private void closeConnection()
    {
        try 
      {
         output.close(); // close output stream
         input.close(); // close input stream
         client.close(); // close socket
      } // end try
      catch ( IOException ioException ) 
      {
         ioException.printStackTrace();
      } // end catch
   } // end method closeConnection


   private void connectToServer() throws IOException
   {      
      System.out.println( "Attempting connection\n" );

      // create Socket to make connection to server
      client = new Socket( InetAddress.getByName( chatServer ), 12345 );

      // display connection information
      System.out.println( "Connected to: " + 
         client.getInetAddress().getHostName() );
   } // end method connectToServer



   private void getStreams() throws IOException
   {
      // set up output stream for objects
      output = new ObjectOutputStream( client.getOutputStream() );         
      output.flush(); // flush output buffer to send header information

      // set up input stream for objects
      input = new ObjectInputStream( client.getInputStream() );     
      System.out.println( "\nGot I/O streams\n" );
   } // end method getStreams

    private void processConnection() throws IOException
    {

     do { 
         try // read message and display it
         {
            message = ( String ) input.readObject(); // read new message
            System.out.println( "\n" + message ); // display message
         } // end try
         catch ( ClassNotFoundException classNotFoundException ) 
         {
            System.out.println( "\nUnknown object type received" );
         } // end catch

      } while ( !message.equals( "SERVER>>> TERMINATE" ) );
   } // end method processConnection

    public String toString()
{
    return "client connected to "+chatServer;
}



public static void main(String []args)
{
  SimpleClient c= new SimpleClient();
  c.runClient();

}



    }

//-------------服务器从这里启动

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.ServerSocket;
import java.net.Socket;


import java.util.ArrayList;

public class SimpleServer //implements Runnable
{
   private ObjectOutputStream output; // output stream to client
   private ObjectInputStream input; // input stream from client
   private ServerSocket server; // server socket
   private Socket connection; // connection to client  
   private int counter=1; //counts connections
   ArrayList<SimpleClient> list;

 /***
  * Runs forever and takes care of alla
  */
   public void runServer()
   {
       try // set up server to receive connections; process connections
      {
         server = new ServerSocket( 12345, 100 ); // create ServerSocket

         while ( true ) 
         {
            try 
            {
               waitForConnection(); // wait for a connection
               getStreams(); // get input & output streams
               processConnection(); // process connection
            } // end try
            catch ( Exception Exception ) 
            {
               System.out.println( "\nSomething bad happened" );
            } // end catch
            finally 
            {
               closeConnection();
               counter++; //  close connection

            } // end finally
   }
       }

      catch ( IOException ioException ) 
      {
         System.out.println("An io error occured while creating a server-socket");
         ioException.printStackTrace();
      } // end catch
   } // end method runServer

   /***
    * Waits for a client's request for connection
    */
   public void waitForConnection()
   {
        try
        {
            connection = server.accept();
            System.out.println("Client with IP and hostname "+connection.getInetAddress().getHostName());
        } catch (IOException ex)
        {
            System.out.println("An error makes connection impossible");
            ex.printStackTrace();
        }

   }


   /***
    * Makes the interconnection of client's and server's stream's
    */
   public void getStreams()
   {
       try
       {

       output=(ObjectOutputStream) connection.getOutputStream();
       input=(ObjectInputStream) connection.getInputStream();
       output.flush();
       System.out.println("Got IO Streams, hell yeah ");

       }

       catch(IOException ioe)
       {
           System.out.println("Cannot get streams");
           ioe.printStackTrace();
       }

   }

   /***
    * Terminates connection
    */
   public void closeConnection()
   {
        try
        {
            output.flush();
            output.close();
            input.close();
        } catch (IOException ex)
        {
            ex.printStackTrace();
        }
   }

   /***
    * Receives messages from client
    */
    public void processConnection()
    {
        String message="Connection successful";

        do // process messages sent from client
      { 
         try // read message and display it
         {
            message = ( String ) input.readObject(); // read new message
            System.out.println("CLIENT>>> "+message);

         } // end try
         catch ( ClassNotFoundException classNotFoundException ) 
         {
            System.out.println( "\nUnknown object type received" );
         } 

         catch(IOException ioe)
         {
             System.out.println("Cannot receive message from clint");
             ioe.printStackTrace();
         }

      } while ( !message.equals( "CLIENT>>> TERMINATE" ) );


    }

    /***
     * Sends data to client
     * @param message
     */
    public void sendData(String message)
    {

        try // send object to client
      {

         output.writeObject( "SERVER>>> " + message );
         output.flush(); // flush output to client
         System.out.println("SERVER>>> " + message);
        }
        catch(IOException ioe)
        {
            ioe.printStackTrace();
        }
    }


    public String toString()
    {
        return "this is a simple server with a total of "+counter+" connections";
    }



   public static void main(String []args)
{
  SimpleServer c= new SimpleServer();
  c.runServer();

}


}

Answer 1

您的服务器只是将 Socket.getOutputStream() 和 Socket.getInputStream() 返回的对象转换为对象流。相反，它必须以与客户端相同的方式使用“new ObjectInputStream()”和“new ObjectOutputStream()”构造对象流。请记住刷新服务器的 ObjectOutputStream。