帮我用python写一个使用QTcpserver和多线程的服务器和客户端通信的代码

在Python中，我们可以使用`pyqt5.QtCore`库中的`QTcpServer`类来创建一个基于TCP的简单服务器，以及`QThread`类来进行多线程处理。以下是简单的服务器端和客户端代码示例：

首先，创建服务器端（server.py）:

import sys
from PyQt5.QtCore import Qt, QTcpServer, QThread
from PyQt5.QtWidgets import QApplication

class ServerThread(QThread):
    data_received = pyqtSignal(str)

    def __init__(self, parent=None):
        super(ServerThread, self).__init__(parent)
        self.server = QTcpServer(self)

    def run(self):
        if not self.server.listen("localhost", 12345):
            print(f"Failed to listen on port {12345}")
        else:
            print(f"Listening on port {self.server.serverPort()}")

        while True:
            client, address = self.server.nextPendingConnection()
            print(f"Accepted connection from {address}")

            client_connection_thread = ClientThread(client, self.data_received)
            client_connection_thread.start()

    def sendDataToAllClients(self, message):
        for socket in self.server.allSockets():
            if socket.state() == QTcpSocket.ConnectedState:
                socket.write(message.encode())
                self.data_received.emit(message)

class ClientThread(QThread):
    def __init__(self, client_socket, signal_data_received, parent=None):
        super(ClientThread, self).__init__(parent)
        self.client_socket = client_socket
        self.signal_data_received = signal_data_received

    def run(self):
        self.receive_data()
        self.client_socket.disconnectFromHost()
        self.wait()

    def receive_data(self):
        while True:
            data = self.client_socket.readLine().data().decode()
            if not data:
                break
            self.signal_data_received.emit(data)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    server = ServerThread()
    server.start()
    sys.exit(app.exec_())

然后，创建客户端（client.py）:

import sys
import socket
from PyQt5.QtCore import Qt, QTimer

def send_message(server_address, message):
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.connect((server_address[0], server_address[1]))
        s.sendall(message.encode())

def main():
    server_address = ("localhost", 12345)
    message = "Hello, Server!"

    timer = QTimer()
    timer.timeout.connect(lambda: send_message(server_address, message))
    timer.start(1000)  # Send a message every second

    app = QApplication(sys.argv)
    sys.exit(app.exec_())

if __name__ == "__main__":
    main()

运行这个例子，服务器会在本地主机的12345端口等待连接。客户端会每秒发送一次消息给服务器。

**相关问题--:**
1. 如何在服务器端处理多个并发连接？
2. 客户端如何实现异步接收服务器响应？
3. 这段代码如何改进以提高性能或增加错误处理？