Java IO 套接字不发送输出流

Question

调试我的代码时，代码停在这里:

while (( msg = reader.readLine())  != null) {
        writer.write("From server: " + msg);
}

我正在从客户端类发送输入，但我不知道我错在哪里，因为服务器从未收到消息。

这是我的整个服务器类:

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


public class Server {

    private BufferedReader reader;
    private PrintWriter writer;
    private int port;

    public Server(int port)
    {
        this.port = port;
    }

    private String getSeverAddress() {      
        String host = null;
        try {
            InetAddress adr = InetAddress.getLocalHost();
            host = adr.getHostAddress();

        } catch (UnknownHostException e) {          
            e.printStackTrace();
        }

        return host;
    }

    public void startServer() {

        print("Contact this sever on address: " + getSeverAddress() + " port: " + port);

        ServerSocket ss = null; 
        Socket socket = null;

        try {
            ss = new ServerSocket(port);
            socket = ss.accept();

            reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            writer = new PrintWriter(socket.getOutputStream(), true);

            String msg = null;

            while (( msg = reader.readLine())  != null) {
                writer.write("From server: " + msg);
                print(msg);

                if(msg.toLowerCase().equals("Bye")) {
                    print("Client left");
                    break;
                }
            }

            ss.close();
            socket.close();
            reader.close();
            writer.close();

        } catch(SocketException e) {
            e.printStackTrace();            
        } catch (IOException i ) {
            i.printStackTrace();
            return;
        }
    }       

    private void print(String msg) {
        System.out.println(msg);
    }

    public static void main(String[] args) {

        Server server = new Server(1111);
        server.startServer();

    }

}

这是客户端类:

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.util.Scanner;


public class Client {

    private Socket client;
    private BufferedReader reader;
    private PrintWriter writer;

    public Client(Socket socket)
    {
        client = socket;

        try{
            reader = new BufferedReader(new InputStreamReader(client.getInputStream()));
            writer = new PrintWriter(client.getOutputStream(), true);

        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public void writeToServer() {       
        print("Write message to server");

        String msg = null;

        try {
            while((msg = reader.readLine()) != null) {
                writer.write("From client: " + msg);
                print(msg);

                if(msg.toLowerCase().equals("quit")) {
                    break;
                }
            }

            reader.close();
            writer.close();

        } catch (IOException e) {
            e.printStackTrace();
        }

    }

    private void print(String msg) {
        System.out.println(msg);
    }

    public static void main(String[] args) {
        Socket socket = null;

        try {
            socket = new Socket("localhost", 1111);

        } catch (Exception e) {
            e.printStackTrace();
        } 

        Client client = new Client(socket);
        client.writeToServer();
    }

}

Answer 1

您的错误是服务器和客户端都在后台发送/接收消息而不打印任何内容。就像当你从客户端发送消息时，服务器收到它并再次写入客户端，它变成无限循环。

以下内容是错误的:

服务器.java

 try {
         while (( msg = reader.readLine())  != null) {
            print(msg);
            if(msg.toLowerCase().equals("bye")) {
                print("Client left");
                break;
            }
            writer.write("From server: " + msg);
        }

应该是循环的最后一个语句 writer.write("From client: "+ msg); 和 if(msg.toLowerCase().equals("Bye")) 应该再见

Client.java

try {
           while((msg = reader.readLine()) != null) {
               print(msg);
                if(msg.toLowerCase().equals("quit")) {
                    break;
                }
              writer.write("From client: " + msg);
            }

它应该是循环的最后一个 writer.write("From client: "+ msg);