用Python实现一个基于文件存储的控制台学生管理系统

放假回家，写写Python玩，10分钟写了一个基于文件存储的控制台学生管理系统，目的是熟悉Json的使用

import json
import os
import atexit
import time

latest_file = ""

def main():
    read_now_time() #程序刚启动时读取上次保存的时间戳文件
    while(True):
        print_menu()
        choose = int(input("输入您的选项："))
        if choose==1:
            add_stu()
        elif choose==2:
            delete_stu()
        elif choose==3:
            update_stu()
        elif choose==4:
            display_stu()
        else:
            exit()

def print_menu():
    print ("====================================================")
    print ("1.添加学生信息 2.删除学生信息 3.更新学生信息 4.显示学生信息 5.退出")
    print ("====================================================")

def add_stu():
    id = input("输入学生证件号：")
    name = input("输入学生姓名：")
    grade = input("输入学生成绩：")
    student = {"id": id, "name": name, "grade": grade}
    students = read_json(from_add=True)
    if not students:
        students = [student]
    else:
        students.append(student)
    write_json(students)

def delete_stu():
    students = read_json()
    id = input("输入要删除学生的证件号：")
    find_id = False
    for student in students:
        if id == student['id']:
            find_id = True
            print ("学生号：" + id + "，姓名：" + student['name'], "，成绩：" + student['grade'])
            sure = input("确认要删除该学生信息吗：Y/N")
            if sure=="Y":
                students.remove(student)
                write_json(students)
            break
    if not find_id:
        print("未找到该学生")

def update_stu():
    print("待定......")

def display_stu():
    students = read_json()
    for student in students:
        print ("----->" + "学生证件号：" + student['id'] + "，学生姓名：" + student['name'] + "，学生成绩：" + student['grade'])

def read_json(from_add=False):
    if not latest_file:
        if not from_add:
            print ("请先添加学生")
        return None
    file_dir = os.path.join(os.getcwd(), "json")
    file_path = os.path.join(file_dir, latest_file)
    with open(file_path, "r+", encoding="utf-8") as fp:
        json_dict = json.load(fp)
        return json_dict

def write_json(json_dict):
    global latest_file
    file_dir = os.path.join(os.getcwd(), "json")
    if not os.path.exists(file_dir):
        os.mkdir(file_dir)
    file_name = str(int(time.time()))
    latest_file = file_name
    file_path = os.path.join(file_dir, file_name)
    json_data = json.dumps(json_dict)
    with open(file_path, "w+") as fp:
        fp.write(json_data)

def read_now_time():
    global latest_file
    now_time_file = os.path.join(os.getcwd(), "now")
    if not os.path.exists(now_time_file):
        print ("时间戳文件不存在，无法定位上次保存的学生数据，重新开始保存数据")
        return
    with open(now_time_file, "r+") as fp:
        latest_file = fp.readline().strip()
        if not latest_file:
            print("时间戳文件为空，无法定位上次保存的学生数据，重新开始保存数据")
        else:
            print("时间戳文件为：" + latest_file + "，加载上次保存的数据......")

#程序退出时，自动保存当前时间戳
@atexit.register
def write_now_time():
    if not latest_file:
        return
    now_time_file = os.path.join(os.getcwd(), "now")
    with open(now_time_file, "w+") as fp:
        fp.write(latest_file)

if __name__ == '__main__':
    main()