@app.route('/api/tstj/') def get_book_data(): sql2 = 'select * from book' data = sql_query_json(sql2) for item in data: item['price'] = str(item['price'].quantize(Decimal('0.00'))) if item['price'] else item['price'] item['uploadtime'] = item['uploadtime'].strftime("%Y-%m-%d") if item['uploadtime'] else item['uploadtime'] item['borrowtime'] = item['borrowtime'].strftime("%Y-%m-%d") if item['borrowtime'] else item['borrowtime'] item['returntime'] = item['returntime'].strftime("%Y-%m-%d") if item['returntime'] else item['returntime'] print(data) return {'result':data,'code':200} @app.route('/api/tsjyadd/', methods=['POST']) def post_xsjyadd_data(): if request.method == 'POST': name = request.json.get('name') press = request.json.get('press') author = request.json.get('author') sql = 'INSERT INTO book (name, press, author) VALUES ("%s", "%s", "%s")'%(name,press,author) sql_ua_json(sql) return jsonify({'code': 200})解释每行代码的意思

这段代码使用了 Python 的 Flask 框架来实现了两个 API 接口：

1. `get_book_data()`：该接口使用 GET 方法获取书籍数据，并将数据转换为 JSON 格式返回给客户端。其中，`sql_query_json()` 函数用于执行 SQL 查询语句并返回 JSON 格式的结果。接着，代码对查询结果的每个元素进行了处理，将价格、上传时间、借阅时间和归还时间转换为字符串类型，并将结果返回给客户端。

2. `post_xsjyadd_data()`：该接口使用 POST 方法向数据库中添加新的书籍数据。首先，代码从请求体中获取书籍的名称、出版社和作者信息，然后使用 SQL INSERT 语句将这些信息插入到数据库中，并返回一个 JSON 格式的响应给客户端。其中，`sql_ua_json()` 函数用于执行 SQL 更新或插入语句并返回 JSON 格式的结果。

相关问题

写@app.route('/api/tstj/') def get_book_data(): import pymysql conn = pymysql.connect(host='127.0.0.1', user='root', password='zp65321333', port=3306, db='libsystem', charset='utf8mb4', cursorclass=cursors.DictCursor) cursor = conn.cursor() sql = 'SELECT * from book' result = cursor.execute(sql) data = cursor.fetchall() return {'result':data,'code':200}的功能原理

这段代码实现了一个Flask的API接口，访问接口地址"/api/tstj/"时，会连接数据库，执行一条查询语句"SELECT * from book"，将查询结果封装成一个字典对象，包含两个键值对：'result'和'code'，其中'result'对应的值是查询结果，'code'对应的值是状态码200，表示请求成功。最后，将这个字典对象作为响应结果返回给前端页面。

具体的过程是：

1. 客户端向服务器发送一个GET请求，请求的地址为"/api/tstj/"。

2. 服务器接收到请求后，调用get_book_data()函数处理这个请求。

3. 在函数内部，使用pymysql模块连接到MySQL数据库，并执行一条查询语句"SELECT * from book"。

4. 调用fetchall()方法获取查询结果，并将结果封装成一个字典对象。

5. 将这个字典对象作为响应结果返回给客户端，并在响应头中设置状态码200。

6. 客户端接收到响应结果后，根据状态码判断请求是否成功，并处理返回的数据。

@app.route('/api/tstj/') def get_book_data(): sql2 = 'select * from book' data = sql_query_json(sql2) for item in data: item['price'] = str(item['price'].quantize(Decimal('0.00'))) if item['price'] else item['price'] item['uploadtime'] = item['uploadtime'].strftime("%Y-%m-%d") if item['uploadtime'] else item['uploadtime'] item['borrowtime'] = item['borrowtime'].strftime("%Y-%m-%d") if item['borrowtime'] else item['borrowtime'] item['returntime'] = item['returntime'].strftime("%Y-%m-%d") if item['returntime'] else item['returntime'] print(data) return {'result':data,'code':200} 解释每行代码的意思

Sure, here is the explanation of each line of code:

1. `@app.route('/api/tstj/')`: This line creates a route for the `/api/tstj/` endpoint in the Flask application.

2. `def get_book_data():`: This line defines a function named `get_book_data` that will handle the requests to the `/api/tstj/` endpoint.

3. `sql2 = 'select * from book'`: This line defines a SQL query to select all columns from the `book` table.

4. `data = sql_query_json(sql2)`: This line executes the SQL query defined in the previous line using the `sql_query_json()` function and saves the results to the `data` variable.

5. `for item in data:`: This line starts a loop that iterates over each item in the `data` list.

6. `item['price'] = str(item['price'].quantize(Decimal('0.00'))) if item['price'] else item['price']`: This line converts the `price` value of the current item to a string with two decimal places using the `quantize()` method of the `Decimal` class. If the `price` value is `None`, it is left unchanged.

7. `item['uploadtime'] = item['uploadtime'].strftime("%Y-%m-%d") if item['uploadtime'] else item['uploadtime']`: This line converts the `uploadtime` value of the current item to a string in the format `YYYY-MM-DD` using the `strftime()` method of the `datetime` class. If the `uploadtime` value is `None`, it is left unchanged.

8. `item['borrowtime'] = item['borrowtime'].strftime("%Y-%m-%d") if item['borrowtime'] else item['borrowtime']`: This line converts the `borrowtime` value of the current item to a string in the format `YYYY-MM-DD` using the `strftime()` method of the `datetime` class. If the `borrowtime` value is `None`, it is left unchanged.

9. `item['returntime'] = item['returntime'].strftime("%Y-%m-%d") if item['returntime'] else item['returntime']`: This line converts the `returntime` value of the current item to a string in the format `YYYY-MM-DD` using the `strftime()` method of the `datetime` class. If the `returntime` value is `None`, it is left unchanged.

10. `print(data)`: This line prints the `data` list to the console.

11. `return {'result':data,'code':200}`: This line returns a dictionary with two keys: `result` and `code`. The `result` key maps to the `data` list (after the modifications made in the loop), and the `code` key maps to the HTTP status code `200` (OK).