我正在使用套接字编写一个简单的聊天程序。该程序在客户端连接到服务器时工作，在开始聊天之前，他们将其名称发送到服务器并在返回时接收唯一ID。这是我的代码无法正常工作的地方。
这是Client类中的代码，它发送名称并接收id：
private void exchangeInformation() {
String temp;
try {
writer.println(name);
temp = reader.readLine();
System.out.println(temp);
temp = reader.readLine();
System.out.println("id has been received : "
+ temp);
this.id = Integer.parseInt(temp);
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't get id from server\n"
+ "Cause: " + e.getMessage() + "\n");
}
}
这是服务器端的代码，它接收名称并发送id：
private void exchangeInformation() {
try {
String n = reader.readLine();
setUserName(n);
System.out.println("name has been received");
writeMessage("Server: Welcome " + userName + "\n");
writeMessage(userId);
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't receive client's name\n"
+ "Cause: " + e.getMessage() + "\n");
}
}
这是服务器端的writeMessage方法：
public synchronized void writeMessage(String message) {
writer.println(message);
}
在双方中，writer是PrintWriter的对象，而reader是BufferedReader的对象。
嗯，问题是，当我向客户端发送userId时，客户端会收到“”而不是正确的数据。代码的其他部分工作正常。
问题是什么，我该如何解决？
此致
编辑：正如评论中所建议的，所有代码：
Client上课：
public class Client {
private String name;
private int id;
private boolean isConnected;
private BufferedReader reader;
//private BufferedWriter writer;
private PrintWriter writer;
private Socket socket;
public Client(String name) {
this.name = name;
}
public boolean getIsConnected() {
return isConnected;
}
public BufferedReader getReader() {
return reader;
}
public void start() {
connect();
exchangeInformation();
new ReceiveFromServer(this).start();
String output;
Scanner in = new Scanner(System.in);
while (isConnected) {
System.out.println("YOU: ");
output = in.nextLine();
writer.print(name + " : " + output);
}
try {
socket.close();
reader.close();
writer.close();
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't close content(s)\n"
+ "Cause: " + e.getMessage() + "\n");
}
}
private void connect() {
System.out.println("Trying to connect to the server...\n");
try {
socket = new Socket("localhost", 4444);
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: User " + name + " couldn't connetct to the server\n"
+ "Cause: " + e.getMessage() + "\n");
}
try {
reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
writer = new PrintWriter(socket.getOutputStream(), true);
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't get socket's InputStream or OutputStream\n"
+ "Cause: " + e.getMessage());
}
System.out.println("You have cnnected to the server successfully");
}
private void exchangeInformation() {
String temp;
try {
writer.println(name);
temp = reader.readLine();
System.out.println(temp);
temp = reader.readLine();
System.out.println("id has been received : "
+ temp);
this.id = Integer.parseInt(temp);
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't get id from server\n"
+ "Cause: " + e.getMessage() + "\n");
}
}
Server上课：
public class Server {
private static Server server = new Server(4444);
private final int PORT;
private List<ClientThread> clients;
private static int counter;
private ServerSocket ss;
private boolean isListening;
private Server(int port) {
this.PORT = port;
clients = new ArrayList<>();
counter = 0;
}
public static Server getServerInstance() {
return server;
}
private int generateId() {
return ++counter;
}
public void start() {
establishConnection();
while (isListening) {
System.out.println("Server is Listening...");
Socket s = null;
try {
s = ss.accept();
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: An error occured while accepting a request\n"
+ "Cause: " + e.getMessage());
}
System.out.println("New connection request has been accepted\n");
ClientThread client = new ClientThread(s, this.generateId());
clients.add(client);
client.start();
}
try {
ss.close();
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't close Server Socket\n"
+ "Cause: " + e.getMessage() + "\n");
}
}
public static synchronized void broadcastMessage(String message) {
Server s = getServerInstance();
for (int i = 0; i < s.clients.size(); i++) {
s.clients.get(i).writeMessage(message);
}
}
private void establishConnection() {
try {
ss = new ServerSocket(4444);
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't establish server socket for connection\n"
+ "Cause: " + e.getMessage() + "\n");
}
System.out.println("Server Socket has been created Successfully\n");
isListening = true;
}
public static void removeClient(int id) {
Server s = getServerInstance();
for (int i = 0; i < s.clients.size(); i++) {
if (id == s.clients.get(i).getId()) {
s.clients.remove(i);
break;
}
}
}
ClientThread上课：
public class ClientThread extends Thread {
private Socket socket;
private BufferedReader reader;
private PrintWriter writer;
private int userId;
private String userName;
private boolean isConnected;
public ClientThread(Socket socket, int id) {
this.socket = socket;
try {
reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
writer = new PrintWriter(socket.getOutputStream(), true);
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't get socket's InputStream or OutputStream\n"
+ "Cause: " + e.getMessage());
}
this.userId = id;
}
public void setUserName(String name) {
this.userName = name;
}
public void setIsConnected(boolean flag) {
isConnected = flag;
}
public BufferedReader getReader() {
return reader;
}
public int getUserId() {
return userId;
}
@Override
public void run() {
exchangeInformation();
isConnected = true;
String input;
while (isConnected) {
try {
input = reader.readLine();
if (input != null) {
if (input.equalsIgnoreCase("logout")) {
logout();
} else {
Server.broadcastMessage(input);
}
}
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't receive message from client\n"
+ "Cause: " + e.getMessage() + "\n");
isConnected = false;
}
}
}
public synchronized void writeMessage(String message) {
writer.println(message);
}
public void writeMessage(int message) {
writer.println(message);
}
private void logout() {
setIsConnected(false);
try {
socket.close();
reader.close();
writer.close();
System.out.println("User " + this.userId + " has loggedout"
);
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't close content(s)\n"
+ "Cause: " + e.getMessage() + "\n");
}
}
private void exchangeInformation() {
try {
String n = reader.readLine();
setUserName(n);
System.out.println("name has been received");
writeMessage("Server: Welcome " + userName + "\n");
writeMessage(userId);
} catch (IOException e) {
System.out.println("Error Occured\n"
+ "Message: Couldn't receive client's name\n"
+ "Cause: " + e.getMessage() + "\n");
}
}
}