Java簡單服務器/客戶端控制檯聊天應用程序

Question

我想創建一個簡單的服務器客戶端應用程序，但我認爲IO Streams存在問題。沒有GUI，因此聊天應該通過控制檯進行（您可以打開2 eclipse來測試它或您使用的任何IDE）。

這裏是我的服務器代碼：

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

public class Server { 
    ServerSocket serverSocket; 
    Socket connection; // connection-to-client 
    ObjectOutputStream output; 
    ObjectInputStream input; 

    public void run() { 
     try { 
      serverSocket = new ServerSocket(6000, 100); 
     } catch (IOException e) { 
      System.err.println("Invalid port number"); 
     } 
     while (true) { 
      try { 
       waitForConnection(); 
       getIOStreams(); 
       processConnection(); 
      } finally { 
       closeConnection(); 
      } 
     } 
    } 

    public void closeConnection() { 
     try { 
      input.close(); 
      output.close(); 
      connection.close(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 

    public void waitForConnection() { 
     System.out.println("Server is ready to accept conenctions"); 
     try { 
      connection = serverSocket.accept(); // code will stop here until a 
               // connection occurs 
      System.out.println("Conenction established with the client"); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 

    public void getIOStreams() { 
     try { 
      output = new ObjectOutputStream(connection.getOutputStream()); 
      output.flush(); // send header information to the client, which 
          // contains info required to create the input stream 
          // object 
      input = new ObjectInputStream(connection.getInputStream()); 
      System.out.println("Server established I/O streams"); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 

    public void processConnection() { 
     sendData("Connection established with the server"); 
     String inputMessage = ""; 
     new Runnable() { 
      Scanner sc = new Scanner(System.in); 

      public void run() { 
       while (true) { 
        sendData(sc.nextLine()); 
       } 
      } 
     }; 
     do { 

      try { 
       inputMessage = (String) input.readObject(); 
       System.out.println(inputMessage); 
      } catch (ClassNotFoundException e) { 
       System.err.println("Object of an unknown type was recieved"); 
      } catch (IOException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 
     } while (inputMessage.equals("QUIT")); 
    } 

    public void sendData(String s) { 
     try { 
      output.writeObject(s); 
      output.flush(); 
      System.out.println("Server: " + s); 
     } catch (IOException e) { 
      System.err.println("Error writting the message"); 
     } 
    } 
} 

，這是我的客戶端代碼

import java.io.IOException; 
import java.io.ObjectInputStream; 
import java.io.ObjectOutputStream; 
import java.net.ServerSocket; 
import java.net.Socket; 
import java.net.UnknownHostException; 
import java.util.Scanner; 

public class Client { 
    ServerSocket serverSocket; 
    Socket clientSocket; 
    ObjectOutputStream output; 
    ObjectInputStream input; 
    String serverAddress = "127.0.0.1"; 

    public void run() { 
     connect2Server(); 
     getIOStreams(); 
     processConnection(); 
     closeConnection(); 
    } 

    public void connect2Server() { 
     System.out.println("Trying to connect to the server"); 
     try { 
      clientSocket = new Socket(serverAddress, 6000); 
     } catch (UnknownHostException e) { 
      System.err.println("Server unavailable"); 
      System.exit(1); 
     } catch (IOException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
    } 

    public void getIOStreams() { 
     try { 
      output = new ObjectOutputStream(clientSocket.getOutputStream()); 
      output.flush(); 
      input = new ObjectInputStream(clientSocket.getInputStream()); 
      System.out.println("Client established I/O Stream"); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 
    } 

    public void processConnection() { 
     sendData("Connection established with the client"); 
     String inputMessage = ""; 
     new Runnable() { 
      Scanner sc = new Scanner(System.in); 

      public void run() { 
       String outputMessage = ""; 
       do { 
        outputMessage = sc.nextLine(); 
        sendData("Client: " + outputMessage); 
       } while (outputMessage.equals("QUIT")); 
      } 
     }; 
     while (true) { 

      try { 
       inputMessage = (String) input.readObject(); 
       System.out.println(inputMessage); 
      } catch (ClassNotFoundException e) { 
       System.err.println("Object of an unknown type was recieved"); 
      } catch (IOException e) { 
       e.printStackTrace(); 
       System.exit(1); 
      } 
     } 
    } 

    public void sendData(String s) { 
     try { 
      output.writeObject(s); 
      output.flush(); 
      System.out.println("Client: " + s); 
     } catch (IOException e) { 
      System.err.println("Error writting the message"); 
     } 
    } 

    public void closeConnection() { 
     try { 
      output.close(); 
      input.close(); 
      clientSocket.close(); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 

    } 
} 

運行服務器或客戶機只在主客戶端/ server.run寫（）; 請告訴我什麼是我的錯誤，以及如何解決它:)

Answer 1

幾點：

1）輸入迴路的結束不正確的條件：

while (inputMessage.equals("QUIT")); // Server#processConnection 

while (outputMessage.equals("QUIT")) // Client#processConnection 

這些應該被否定（「！ 「）。

2）你應該開始你System.in閱讀線程：

new Thread() { // instead of `Runnable` 
    ... 
}.start(); 

3），你應該打破服務器偵聽環的一些例外，比如EOFException這意味着客戶端已斷開。