Java套接字无法将数据发送到服务器[重复]

Question

我正在编写一个 java 套接字程序，用于将 JSON 对象从客户端发送到另一个客户端。现在，我只是通过发送控制台输入的字符串数据来测试它。当我在控制台中输入内容并将其发送到服务器时，服务器应将其打印出来并将其发送回客户端，然后客户端也应将其打印出来。但是我的服务器程序在控制台中没有显示任何内容，客户端也没有。我找不到问题出在哪里。

服务器：

public class GameServer {
private Socket socket;
private ServerSocket serverSocket;
private ArrayList<GameServerThread> threads;

public GameServer(){
    try{
        //Create new server socket
        serverSocket = new ServerSocket(1234,100);
        System.out.println("Waiting for clients ...");
        threads = new ArrayList<GameServerThread>();
        //Receive request from client
        while(true){
            socket = serverSocket.accept();
            //Create new Thread once receive a request
            new Thread(new GameServerThread(socket, this)).start();     
        }

    }catch(IOException e){
        System.out.println("Failed to create socket!");
        e.printStackTrace();
    }finally{
        try {
            serverSocket.close();
        } catch (IOException e) {               
            e.printStackTrace();
        }
    }       
}   



public ArrayList<GameServerThread> getAllThreads(){
    return this.threads;
}


public void addNewThread(GameServerThread t){
    this.threads.add(t);
}



public static void main(String args[]){
    GameServer server = new GameServer();
}
}

服务器线程：

public class GameServerThread extends Thread{
private Socket socket;
private GameServer server;
private OutputStreamWriter writer;
private BufferedReader reader;
String userName;

public GameServerThread(Socket s, GameServer srv) throws UnsupportedEncodingException, IOException{
    System.out.println("Succeeded to connect with one client!");
    this.socket = s;
    this.server = srv;
    writer = new OutputStreamWriter(this.socket.getOutputStream(), "UTF-8");
    reader = new BufferedReader(new InputStreamReader(this.socket.getInputStream(), "UTF-8"));  
    this.server.addNewThread(this);
}


public void run(){
    try{
        while(true){
            receive();
        }
    }catch(SocketException e){
        e.printStackTrace();
    }catch(IOException e){
        e.printStackTrace();
    }finally{       
        try {
            this.socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}


private void receive() throws IOException{
    String str = null;
    while((str=reader.readLine()) != null){
        System.out.println(str);
        sendToOther(str);       }
}


public void send(String msg){
    try{
        writer.write(msg);
        writer.flush();
    }catch(IOException e){
        e.printStackTrace();
    }
}


private void sendToOther(String msg){
    for(GameServerThread thread: this.server.getAllThreads()){
        //if(!thread.equals(this)){
            thread.send(msg);
        //}
    }
}

客户：

public class GameClient {
private Socket socket;
private String serverIP;
private OutputStreamWriter writer;
private BufferedReader reader;

public GameClient(String host){
    this.serverIP = host;

    try{
        //Connect to server
        socket = new Socket(InetAddress.getByName(serverIP), 1234);
        writer = new OutputStreamWriter(this.socket.getOutputStream(), "UTF-8");
        reader = new BufferedReader(new InputStreamReader(this.socket.getInputStream(), "UTF-8"));
        //Start a new thread for reading from server
        new Thread(new GameClientThread(socket)).start();

        Scanner scanner = new Scanner(System.in);
        System.out.println("Write something: ");
        String str = "";
        while((str = scanner.nextLine()) != null){
            writer.write(str);
            writer.flush();
            System.out.println("Write something: ");
        }
    }catch(IOException e){
        System.out.println("Client failed to connect!");
        e.printStackTrace();
}
}

客户端线程：

public class GameClientThread extends Thread{
private Socket socket;
private BufferedReader reader;

//private OutputStreamWriter writer;
//private String userName = "";

public GameClientThread(Socket soc){
    this.socket = soc;

    try{
        reader = new BufferedReader(new InputStreamReader (this.socket.getInputStream(), "UTF-8"));
    }catch(IOException e){
        e.printStackTrace();
    }


}


public void run(){
    while(true){
        receive();
    }
}


private void receive(){
    String msg;
    try {
        msg = reader.readLine();
        System.out.println(msg);
    } catch (IOException e) {
        e.printStackTrace();
    }
}
}

Answer 1

BufferedReader.readLine 期望在每一行的末尾有一个新行（\n、\r 或 \r\n），但是当你写数据时你不会写一个新行。每次编写尚未以新行结尾的字符串时添加writer.write('\n');。