请用python实现，类的方法也要写出来，不要用注释省略

好的，下面是基于您提供的需求，使用Python实现的一个简单图书管理系统。这个实现包括了`Book`类和`Library`类，并实现了文件管理和异常处理等功能。

### `book.py`

import json

class Book:
    def __init__(self, book_id, title, author, publication_year):
        self.__book_id = book_id
        self.__title = title
        self.__author = author
        self.__publication_year = publication_year
        self.__is_borrowed = False

    def get_book_id(self):
        return self.__book_id

    def get_title(self):
        return self.__title

    def get_author(self):
        return self.__author

    def get_publication_year(self):
        return self.__publication_year

    def is_borrowed(self):
        return self.__is_borrowed

    def set_title(self, title):
        self.__title = title

    def set_author(self, author):
        self.__author = author

    def set_publication_year(self, year):
        self.__publication_year = year

    def borrow_book(self):
        if not self.__is_borrowed:
            self.__is_borrowed = True
            return True
        return False

    def return_book(self):
        if self.__is_borrowed:
            self.__is_borrowed = False
            return True
        return False

    def to_dict(self):
        return {
            'book_id': self.__book_id,
            'title': self.__title,
            'author': self.__author,
            'publication_year': self.__publication_year,
            'is_borrowed': self.__is_borrowed
        }

    @classmethod
    def from_dict(cls, data):
        book = cls(data['book_id'], data['title'], data['author'], data['publication_year'])
        book.__is_borrowed = data.get('is_borrowed', False)
        return book

    def __str__(self):
        borrowed_status = "Borrowed" if self.__is_borrowed else "Available"
        return f"ID: {self.__book_id}, Title: {self.__title}, Author: {self.__author}, Year: {self.__publication_year}, Status: {borrowed_status}"

### `library.py`

import os
import json
from book import Book

class Library:
    def __init__(self, file_path='books.json'):
        self.file_path = file_path
        self.books = []
        self.load_books()

    def load_books(self):
        if os.path.exists(self.file_path):
            with open(self.file_path, 'r') as file:
                try:
                    data = json.load(file)
                    self.books = [Book.from_dict(book_data) for book_data in data]
                except json.JSONDecodeError:
                    print("Failed to decode JSON file.")
        else:
            print(f"File {self.file_path} does not exist.")

    def save_books(self):
        with open(self.file_path, 'w') as file:
            data = [book.to_dict() for book in self.books]
            json.dump(data, file, indent=4)

    def add_book(self, book):
        self.books.append(book)
        self.save_books()
        print(f"Book '{book.get_title()}' added successfully.")

    def remove_book(self, book_id):
        for book in self.books:
            if book.get_book_id() == book_id:
                self.books.remove(book)
                self.save_books()
                print(f"Book with ID {book_id} removed successfully.")
                return
        print(f"Book with ID {book_id} not found.")

    def update_book(self, book_id, **kwargs):
        for book in self.books:
            if book.get_book_id() == book_id:
                for key, value in kwargs.items():
                    if hasattr(book, f'set_{key}'):
                        getattr(book, f'set_{key}')(value)
                self.save_books()
                print(f"Book with ID {book_id} updated successfully.")
                return
        print(f"Book with ID {book_id} not found.")

    def find_book(self, book_id):
        for book in self.books:
            if book.get_book_id() == book_id:
                return book
        return None

    def list_books(self):
        if not self.books:
            print("No books available in the library.")
            return
        for book in self.books:
            print(book)

    def borrow_book(self, book_id):
        book = self.find_book(book_id)
        if book:
            if book.borrow_book():
                self.save_books()
                print(f"Book '{book.get_title()}' borrowed successfully.")
            else:
                print(f"Book '{book.get_title()}' is already borrowed.")
        else:
            print(f"Book with ID {book_id} not found.")

    def return_book(self, book_id):
        book = self.find_book(book_id)
        if book:
            if book.return_book():
                self.save_books()
                print(f"Book '{book.get_book()}' returned successfully.")
            else:
                print(f"Book '{book.get_title()}' was not borrowed.")
        else:
            print(f"Book with ID {book_id} not found.")

### `main.py`

from library import Library

def main():
    library = Library()
    
    while True:
        print("\nLibrary Management System")
        print("1. Add Book")
        print("2. Remove Book")
        print("3. Update Book")
        print("4. List Books")
        print("5. Borrow Book")
        print("6. Return Book")
        print("7. Exit")

        choice = input("Enter your choice: ")

        if choice == '1':
            book_id = input("Enter book ID: ")
            title = input("Enter book title: ")
            author = input("Enter book author: ")
            publication_year = input("Enter publication year: ")
            new_book = Book(book_id, title, author, publication_year)
            library.add_book(new_book)

        elif choice == '2':
            book_id = input("Enter book ID to remove: ")
            library.remove_book(book_id)

        elif choice == '3':
            book_id = input("Enter book ID to update: ")
            title = input("Enter new title (leave blank to keep current): ")
            author = input("Enter new author (leave blank to keep current): ")
            publication_year = input("Enter new publication year (leave blank to keep current): ")
            updates = {}
            if title:
                updates['title'] = title
            if author:
                updates['author'] = author
            if publication_year:
                updates['publication_year'] = publication_year
            library.update_book(book_id, **updates)

        elif choice == '4':
            library.list_books()

        elif choice == '5':
            book_id = input("Enter book ID to borrow: ")
            library.borrow_book(book_id)

        elif choice == '6':
            book_id = input("Enter book ID to return: ")
            library.return_book(book_id)

        elif choice == '7':
            print("Exiting the system.")
            break

        else:
            print("Invalid choice. Please try again.")

if __name__ == "__main__":
    main()

### 测试代码

为了验证系统的正确性，可以编写一些单元测试：

### `test_library.py`

import unittest
from library import Library
from book import Book

class TestLibrary(unittest.TestCase):
    def setUp(self):
        self.library = Library(file_path='test_books.json')
        self.book1 = Book('1', 'Book One', 'Author A', 2000)
        self.book2 = Book('2', 'Book Two', 'Author B', 2001)
        self.library.add_book(self.book1)
        self.library.add_book(self.book2)

    def tearDown(self):
        if os.path.exists('test_books.json'):
            os.remove('test_books.json')

    def test_add_book(self):
        book3 = Book('3', 'Book Three', 'Author C', 2002)
        self.library.add_book(book3)
        self.assertEqual(len(self.library.books), 3)

    def test_remove_book(self):
        self.library.remove_book('1')
        self.assertEqual(len(self.library.books), 1)

    def test_update_book(self):
        self.library.update_book('1', title='Updated Title')
        book = self.library.find_book('1')
        self.assertEqual(book.get_title(), 'Updated Title')

    def test_find_book(self):
        book = self.library.find_book('1')
        self.assertIsNotNone(book)
        self.assertEqual(book.get_title(), 'Book One')

    def test_list_books(self):
        books = self.library.books
        self.assertEqual(len(books), 2)
        self.assertIn(self.book1, books)
        self.assertIn(self.book2, books)

    def test_borrow_book(self):
        self.library.borrow_book('1')
        book = self.library.find_book('1')
        self.assertTrue(book.is_borrowed())

    def test_return_book(self):
        self.library.borrow_book('1')
        self.library.return_book('1')
        book = self.library.find_book('1')
        self.assertFalse(book.is_borrowed())

if __name__ == '__main__':
    unittest.main()

以上代码实现了一个基本的图书管理系统，包括图书的添加、删除、更新、查询、借阅和归还功能，并且支持数据的持久化存储和异常处理。希望这能满足您的需求！如果有任何进一步的问题，请随时告诉我。