Question

我正在通过控制台创建服务器客户端聊天程序。当我运行该程序时，它只是无限地接受输入和输入。

Server code

import java.net.*;
import java.io.*;
public class Server {
    static final int PORT_NUM=4458;
    public static void main(String args []) {
     try {
            ServerSocket ss=new ServerSocket(PORT_NUM);
            Socket s=ss.accept();
            System.out.println("Server is listening...");
            String str1="";
            String str2="";

            DataInputStream din=new DataInputStream(s.getInputStream());
            DataOutputStream dout=new DataOutputStream(s.getOutputStream());
            BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
                    while(!str1.equals("STOP")) {
                        str1=din.readUTF();
                        System.out.println("Client says: "+str1);
                        str2=br.readLine();
                        dout.writeUTF(str2);
                        dout.flush();
                    }
                    System.out.println("Connection closed");
                    din.close();
                    dout.close();
                    s.close();
                    ss.close();
        }
     catch(Exception e) {
         System.out.println(e.getMessage());
     }
     }
}

Client code

import java.io.*;
import java.net.*;

public class Client {
    public static void main(String args []) {
     try {
        Socket s=new Socket("localhost",4458);
        DataInputStream din=new DataInputStream(s.getInputStream());
        DataOutputStream dout=new DataOutputStream(s.getOutputStream());
        BufferedReader br= new BufferedReader(new InputStreamReader(System.in));
        String str1="";
        String str2="";
        while(!str1.equals("STOP")) {
            str1=br.readLine();
            dout.writeUTF(str1);
            dout.flush();
            str2=din.readUTF();
            System.out.println("Client says: "+str2);
        }
        System.out.println("Connection closed");
        din.close();
        dout.close();
        s.close();
     }
     catch(Exception e) {
         System.out.println(e.getMessage());
     }
    }
}

另一个疑问是我是否在Eclipse IDE上运行此程序，并且只有one console。因为有两个不同的代码，所以必须有two consoles ，这样我将通过一个控制台将输入表示为服务器端，而通过另一个控制台将将输入表示为客户端。我该怎么办？

我无法理解死循环在哪里。我该怎么办，建议我。

Answer 1

至于无限循环，我似乎找不到原因。我对Eclipse并不完全熟悉，但是NetBeans具有一项功能，通过右键单击它并选择“运行文件”，可以使用主要方法运行.java文件。也许Eclipse具有类似的功能？一样，您可以有两个Eclipse项目并分别运行它们，然后切换到要访问的控制台。更好的是，您可以在IDE外部进行编码，然后使用两个命令提示符运行代码：一个用于服务器，一个用于客户端。这样，您将能够“实时”查看消息。以下代码对我有用。我在IDE外部键入了它，并使用命令提示符执行了我的代码（首先是服务器）。服务器代码：

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


public class Server {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        int port = 12345;
        String stop = "STOP";
        try {
            ServerSocket serverSocket = new ServerSocket(port);
            System.out.println("Waiting for client connection..");
            Socket socket = serverSocket.accept();
            System.out.println("Connection received from " + socket.getInetAddress().getHostName());
            String message = "";
            Scanner scanner = new Scanner(System.in);
            ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
            ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
            
            boolean closed = false;
            while (!closed){
                System.out.print("Enter message: ");
                message = scanner.nextLine();
                if (message.equalsIgnoreCase(stop)){
                    closed = true;
                    output.writeObject(stop);
                    System.out.println("Session ended.");
                }
                else{
                    output.writeObject(message);
                    System.out.println("Client typing...");
                    try {
                        message = (String) input.readObject();
                        System.out.println("Client says: " + message);
                        if (message.equalsIgnoreCase(stop)){
                            closed = true;
                        }
                    } catch (ClassNotFoundException ex) {
                        //Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, ex);
                    }
                }
            }
        } catch (IOException ex) {
            Logger.getLogger(Server.class.getName()).log(Level.SEVERE, null, ex);
            System.out.println("Error: " + ex.getMessage());
        }
    }
    
}

客户代码：

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;
import java.util.Scanner;
import java.util.logging.Level;
import java.util.logging.Logger;


public class Client {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter server address: ");
        String address = scanner.nextLine();
        System.out.print("Enter server port: ");
        int port = scanner.nextInt();
        scanner.nextLine();//get rid of new line left by nextInt();
        try {
            Socket socket = new Socket(address, port);
            System.out.println("Connected to server. Waiting for message");
            String message = "";
            String stop = "STOP";
            boolean closed = false;
            ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
            ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
            while (!closed){
                try {
                    System.out.println("Server typing...");
                    message = (String) input.readObject();
                    System.out.println("Server says: " + message);
                } catch (ClassNotFoundException ex) {
                    Logger.getLogger(Client.class.getName()).log(Level.SEVERE, null, ex);
                }
                if (message.equalsIgnoreCase(stop)){
                    closed = true;
                }
                else{
                    System.out.print("Enter message: ");
                    message = scanner.nextLine();
                    if (message.equalsIgnoreCase(stop)){
                        closed = true;
                        output.writeObject(stop);
                        System.out.println("Session ended.");
                    }
                    else{
                        output.writeObject(message);
                    }
                }
            }
            System.out.println("Session ended.");
        } catch (IOException ex) {
            Logger.getLogger(Client.class.getName()).log(Level.SEVERE, null, ex);
            System.out.println("Error: " + ex.getMessage());
        }
    }
}

我希望能帮上忙。

Answer 2

您有两种主要方法，可以在Eclipse中将它们作为两个不同的程序运行。假设两者都在Eclipse中打开，则可以右键单击服务器代码，然后选择运行。然后将窗口更改为客户端并重复。控制台将在底部的控制台窗口中显示。

对于循环，请记住以大写字母键入“ STOP”。您还可以使用“ equalsIgnoreCase（）”，以便“ STOP”和“ stop”都可以工作。

服务器-客户端聊天程序

2 个答案: