作业 —— day77

1.写一个类，有个name属性，如果name赋值为非字符串，就不让放

class Name(object):
    def __init__(self, name):
        self.name = name

    def __setattr__(self, key, name):
        if isinstance(name, str):
            self.__dict__[key] = name
        else:
            print('Name Error：不是字符串，无效')

    def __getattr__(self, item):
        return self[item]


user = Name(name='xxq')
user.name = 123123
print('用户名为：', user.name)

老师的方法：

# 自定义异常
class NotStrException(BaseException):
    def __init__(self, msg):
        self.msg = msg

    def __str__(self):
        return self.msg


class Person():
    def __setattr__(self, key, value):
        if isinstance(value, str):  # isinstance   issubclass
            # setattr(self,key,value)   #内部是这么执行的self.key=value
            # self.__dict__[key]=value
            object.__setattr__(self, key, value)
        else:
            # print("你不能放")
            raise NotStrException('不是字符串异常')


person = Person()

try:
    # person.name=99
    person.name = 'xxq'
except NotStrException as e:
    print(e)

print(person.name)

2.通过上下文管理器写一个mysql的连接，通过with管理

import pymysql


class Mysql:
    def __enter__(self):
        self.conn = pymysql.connect(host='127.0.0.1',
                                    user='root',
                                    password="123456",
                                    database='0701test',
                                    port=3306)
        self.cursor = self.conn.cursor(cursor=pymysql.cursors.DictCursor)  # 查出来数据是字典格式
        return self.cursor

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.cursor.close()


with Mysql() as db:
    sql = 'select * from info'
    db.execute(sql)
    result = db.fetchall()
    for i in result:
        print(i)

老师的代码：

import pymysql


class Mysql():
    def __enter__(self):
        self.conn = pymysql.connect(host='127.0.0.1', user='root', password="123456",
                                    database='mytest', port=3306)
        return self.conn  # 会被as 后的对象拿到

    def __exit__(self, exc_type, exc_val, exc_tb):
        self.conn.close()


with Mysql() as mysql:
    mysql.cursor()

3.使用django实现token功能

待发布...