使用python+pyqt5+mysql以及三层架构实现一个信息管理系统的代码编写，要求有实体类

好的，以下是一个使用 Python、PyQt5 和 MySQL 实现信息管理系统的代码示例，采用三层架构。

首先，我们需要安装 PyMySQL 库，它是 Python 与 MySQL 数据库通信的驱动库。可以使用以下命令进行安装：

pip install PyMySQL

接下来，我们需要创建一个 MySQL 数据库和一个名为 "info" 的表，用于存储学生信息。表结构如下：

CREATE TABLE `info` (
    `id` int(11) NOT NULL AUTO_INCREMENT,
    `name` varchar(20) NOT NULL,
    `age` int(11) NOT NULL,
    `gender` varchar(10) NOT NULL,
    PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

然后，我们需要创建一个实体类 Student，用于存储学生信息：

class Student:
    def __init__(self, id, name, age, gender):
        self.id = id
        self.name = name
        self.age = age
        self.gender = gender

接下来，我们需要创建一个数据访问层 InfoDAO，用于与数据库进行交互：

import pymysql

class InfoDAO:
    def __init__(self):
        self.conn = pymysql.connect(host='localhost', port=3306, user='root', password='123456', db='test')
        self.cursor = self.conn.cursor()

    def __del__(self):
        self.cursor.close()
        self.conn.close()

    def add_student(self, student):
        sql = "INSERT INTO info(name, age, gender) VALUES(%s, %s, %s)"
        self.cursor.execute(sql, (student.name, student.age, student.gender))
        self.conn.commit()

    def delete_student(self, id):
        sql = "DELETE FROM info WHERE id=%s"
        self.cursor.execute(sql, id)
        self.conn.commit()

    def update_student(self, student):
        sql = "UPDATE info SET name=%s, age=%s, gender=%s WHERE id=%s"
        self.cursor.execute(sql, (student.name, student.age, student.gender, student.id))
        self.conn.commit()

    def get_student(self, id):
        sql = "SELECT * FROM info WHERE id=%s"
        self.cursor.execute(sql, id)
        result = self.cursor.fetchone()
        if result:
            return Student(result[0], result[1], result[2], result[3])
        else:
            return None

    def get_all_students(self):
        sql = "SELECT * FROM info"
        self.cursor.execute(sql)
        results = self.cursor.fetchall()
        students = []
        for result in results:
            students.append(Student(result[0], result[1], result[2], result[3]))
        return students

最后，我们需要创建一个业务逻辑层 InfoService，用于处理业务逻辑：

class InfoService:
    def __init__(self):
        self.dao = InfoDAO()

    def add_student(self, name, age, gender):
        student = Student(None, name, age, gender)
        self.dao.add_student(student)

    def delete_student(self, id):
        self.dao.delete_student(id)

    def update_student(self, id, name, age, gender):
        student = self.dao.get_student(id)
        if student:
            student.name = name
            student.age = age
            student.gender = gender
            self.dao.update_student(student)

    def get_student(self, id):
        return self.dao.get_student(id)

    def get_all_students(self):
        return self.dao.get_all_students()

现在，我们可以创建一个 GUI 界面，使用 PyQt5 实现信息管理系统的用户界面。下面是一个简单的示例：

import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QLabel, QLineEdit, QPushButton, QTableWidget, QTableWidgetItem, QVBoxLayout, QHBoxLayout
from InfoService import InfoService

class InfoWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle('信息管理系统')
        self.setGeometry(300, 300, 600, 400)

        # 添加学生
        self.name_label = QLabel('姓名', self)
        self.name_label.move(50, 50)
        self.name_edit = QLineEdit(self)
        self.name_edit.move(120, 50)
        self.age_label = QLabel('年龄', self)
        self.age_label.move(50, 100)
        self.age_edit = QLineEdit(self)
        self.age_edit.move(120, 100)
        self.gender_label = QLabel('性别', self)
        self.gender_label.move(50, 150)
        self.gender_edit = QLineEdit(self)
        self.gender_edit.move(120, 150)
        self.add_button = QPushButton('添加', self)
        self.add_button.move(120, 200)
        self.add_button.clicked.connect(self.add_student)

        # 删除学生
        self.id_label = QLabel('ID', self)
        self.id_label.move(300, 50)
        self.id_edit = QLineEdit(self)
        self.id_edit.move(350, 50)
        self.delete_button = QPushButton('删除', self)
        self.delete_button.move(350, 100)
        self.delete_button.clicked.connect(self.delete_student)

        # 修改学生
        self.update_label = QLabel('修改', self)
        self.update_label.move(500, 50)
        self.update_name_label = QLabel('姓名', self)
        self.update_name_label.move(450, 100)
        self.update_name_edit = QLineEdit(self)
        self.update_name_edit.move(520, 100)
        self.update_age_label = QLabel('年龄', self)
        self.update_age_label.move(450, 150)
        self.update_age_edit = QLineEdit(self)
        self.update_age_edit.move(520, 150)
        self.update_gender_label = QLabel('性别', self)
        self.update_gender_label.move(450, 200)
        self.update_gender_edit = QLineEdit(self)
        self.update_gender_edit.move(520, 200)
        self.update_button = QPushButton('修改', self)
        self.update_button.move(520, 250)
        self.update_button.clicked.connect(self.update_student)

        # 显示学生
        self.table = QTableWidget(self)
        self.table.setGeometry(50, 250, 300, 100)
        self.table.setColumnCount(4)
        self.table.setHorizontalHeaderLabels(['ID', '姓名', '年龄', '性别'])
        self.show_button = QPushButton('显示', self)
        self.show_button.move(50, 370)
        self.show_button.clicked.connect(self.show_students)

    def add_student(self):
        name = self.name_edit.text()
        age = int(self.age_edit.text())
        gender = self.gender_edit.text()
        service = InfoService()
        service.add_student(name, age, gender)
        self.name_edit.setText('')
        self.age_edit.setText('')
        self.gender_edit.setText('')

    def delete_student(self):
        id = int(self.id_edit.text())
        service = InfoService()
        service.delete_student(id)
        self.id_edit.setText('')

    def update_student(self):
        id = int(self.id_edit.text())
        name = self.update_name_edit.text()
        age = int(self.update_age_edit.text())
        gender = self.update_gender_edit.text()
        service = InfoService()
        service.update_student(id, name, age, gender)
        self.update_name_edit.setText('')
        self.update_age_edit.setText('')
        self.update_gender_edit.setText('')

    def show_students(self):
        service = InfoService()
        students = service.get_all_students()
        self.table.setRowCount(len(students))
        for i in range(len(students)):
            student = students[i]
            id_item = QTableWidgetItem(str(student.id))
            name_item = QTableWidgetItem(student.name)
            age_item = QTableWidgetItem(str(student.age))
            gender_item = QTableWidgetItem(student.gender)
            self.table.setItem(i, 0, id_item)
            self.table.setItem(i, 1, name_item)
            self.table.setItem(i, 2, age_item)
            self.table.setItem(i, 3, gender_item)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = InfoWindow()
    window.show()
    sys.exit(app.exec_())

现在，我们就完成了一个简单的信息管理系统。用户可以添加、删除、修改和显示学生信息。