python，Pyqt5 实现FTP服务器与客户端文件上传，下载

可以使用Python和PyQt5来实现FTP服务器和客户端文件上传和下载功能。首先，你需要使用Python内置的ftplib模块来处理FTP连接和操作。下面是一个简单的示例代码：

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QMessageBox
from PyQt5.QtCore import Qt
from ftplib import FTP

class FTPClient(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()
    
    def initUI(self):
        self.setWindowTitle("FTP Client")
        self.setGeometry(100, 100, 300, 200)
        
        self.host = "ftp.example.com"  # FTP服务器地址
        self.user = "username"  # FTP登录用户名
        self.password = "password"  # FTP登录密码
        
        self.ftp = FTP()
        
        self.connectFTP()
        
    def connectFTP(self):
        try:
            self.ftp.connect(self.host)
            self.ftp.login(self.user, self.password)
            self.statusBar().showMessage("Connected to FTP server")
        except Exception as e:
            QMessageBox.critical(self, "Error", str(e))
            sys.exit()
        
    def uploadFile(self, filename):
        try:
            with open(filename, "rb") as file:
                self.ftp.storbinary("STOR " + filename, file)
            self.statusBar().showMessage("File uploaded successfully")
        except Exception as e:
            QMessageBox.critical(self, "Error", str(e))
        
    def downloadFile(self, filename):
        try:
            with open(filename, "wb") as file:
                self.ftp.retrbinary("RETR " + filename, file.write)
            self.statusBar().showMessage("File downloaded successfully")
        except Exception as e