173 lines
4.6 KiB
Python
173 lines
4.6 KiB
Python
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"""
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06 数据持久化版本：学生增删改查
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持久化：
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程序运行时，数据在内存里。
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程序结束后，内存数据会消失。
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如果希望下次打开程序还能看到数据，就要把数据保存到文件或数据库。
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本文件使用 JSON 文件保存数据。
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运行后会在当前目录生成 students.json。
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"""
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import json
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from pathlib import Path
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DATA_FILE = Path("students.json")
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class Student:
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def __init__(self, student_id, name, age, phone):
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self.id = student_id
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self.name = name
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self.age = age
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self.phone = phone
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def to_dict(self):
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return {
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"id": self.id,
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"name": self.name,
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"age": self.age,
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"phone": self.phone,
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}
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@classmethod
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def from_dict(cls, data):
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return cls(
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data["id"],
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data["name"],
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data["age"],
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data["phone"],
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)
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def __str__(self):
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return f"ID: {self.id}, 姓名: {self.name}, 年龄: {self.age}, 电话: {self.phone}"
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class StudentManager:
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def __init__(self):
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self.students = []
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self.next_id = 1
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self.load()
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def load(self):
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if not DATA_FILE.exists():
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return
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with DATA_FILE.open("r", encoding="utf-8") as file:
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data = json.load(file)
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self.next_id = data.get("next_id", 1)
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self.students = [
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Student.from_dict(item)
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for item in data.get("students", [])
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]
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def save(self):
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data = {
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"next_id": self.next_id,
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"students": [student.to_dict() for student in self.students],
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}
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with DATA_FILE.open("w", encoding="utf-8") as file:
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json.dump(data, file, ensure_ascii=False, indent=2)
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def add_student(self):
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name = input("姓名：").strip()
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age = input("年龄：").strip()
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phone = input("电话：").strip()
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self.students.append(Student(self.next_id, name, age, phone))
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self.next_id += 1
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self.save()
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print("添加成功")
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def list_students(self):
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if not self.students:
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print("暂无学生")
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return
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for student in self.students:
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print(student)
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def find_student_by_id(self, student_id):
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for student in self.students:
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if str(student.id) == str(student_id):
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return student
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return None
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def search_student(self):
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keyword = input("请输入要查询的姓名：").strip()
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result = [student for student in self.students if student.name == keyword]
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if not result:
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print("没有找到该学生")
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return
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for student in result:
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print(student)
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def update_student(self):
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student_id = input("请输入要修改的学生 ID：").strip()
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student = self.find_student_by_id(student_id)
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if student is None:
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print("没有找到该学生")
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return
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student.name = input("新姓名：").strip()
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student.age = input("新年龄：").strip()
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student.phone = input("新电话：").strip()
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self.save()
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print("修改成功")
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def delete_student(self):
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student_id = input("请输入要删除的学生 ID：").strip()
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student = self.find_student_by_id(student_id)
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if student is None:
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print("没有找到该学生")
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return
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self.students.remove(student)
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self.save()
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print("删除成功")
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class Application:
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def __init__(self):
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self.manager = StudentManager()
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self.menu = {
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"1": ("添加学生", "add_student"),
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"2": ("查看所有学生", "list_students"),
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"3": ("查询学生", "search_student"),
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"4": ("修改学生", "update_student"),
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"5": ("删除学生", "delete_student"),
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}
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def show_menu(self):
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print("\n====== 学生管理系统：JSON 持久化版本 ======")
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for key, value in self.menu.items():
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title, _ = value
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print(f"{key}. {title}")
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print("0. 退出")
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def run(self):
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while True:
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self.show_menu()
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choice = input("请输入操作编号：").strip()
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if choice == "0":
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print("程序结束")
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break
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if choice not in self.menu:
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print("输入有误，请重新输入")
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continue
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_, method_name = self.menu[choice]
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getattr(self.manager, method_name)()
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if __name__ == "__main__":
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app = Application()
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app.run()
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