Python全栈之路----面向对象开发----反射

 

反射：通过字符串映射到对象的属性

class People:
    country = 'China'
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def talk(self):
        print('%s is talking' %self.name)

obj = People('egon', 18)

print(obj.name)  # obj.__dict__['name']
print(obj.talk)

choice = input('>>:')  # choice = 'name'
print(obj.choice)  # print(obj.'name')

hasattr(obj, 'name')  # 查找 obj.name 或 obj.__dict__['name'] 是否存在，返回True or False
print(getattr(obj, 'name', None))  # 有的话返回方法或数据值 ，可设置默认值为None，在没有的情况下返回默认值None，不设置默认值会报错
setattr(obj, 'sex', 'male')  # 修改 obj.sex = 'male'
delattr(obj, 'age')   # 删除 obj.age

反射的应用：通过输入，直接调用相应命令

class Service:
    def run(self):  # 运行功能
        while True:
            inp = input('>>:').strip()  # inp = 'get a.txt'
            cmds = inp.split()  # cmds = ['get','a.txt']

            if hasattr(self, cmds[0]):
                func = getattr(self, cmds[0])
                func(cmds)

    def get(self, cmds):  # 下载功能
        print('get...', cmds)

    def put(self, cmds):  # 上传
        print('put...', cmds)

obj = Service()
obj.run()