面向对象-反射

编辑本随笔

当调用一个类中不存在得属性或方法，类默认调用__getarrt__()方法，可以自定义

def test():
    print("Test")

T={"six":test}

class Student(object):
    def __init__(self,name,age):
        self.name=name
        self.age=age
    def __getattr__(self, item):
        if item in T:
            return T[item]
s=Student('y',18)
print(s.six)
s.six()

反射：通过字符串映射到对象的属性，该方法实用于对象与类

hasattr(obj,'name')

class People:
    def __init__(self,name,age):
        self.name=name
        self.age=age
    def talk(self):
        print("%s is talking" % self.name)
obj=People('ya',22)
#判断对象obj下面有没有obj.name属性
print(hasattr(obj,'name'))
print(hasattr(obj,'talk'))

getattr(obj,'str','defaultstr')拿到对象属性

print(getattr(obj,'name',None))
print(getattr(obj,'talk',None))

setattr(obj,'sex','male')设置对象属性

setattr(obj,'sex','male')
print(obj.sex)

delattr(obj,'str')删除对象属性

print(obj.__dict__)
delattr(obj,'age')
print(obj.__dict__)

反射的应用

class service:
    def run(self):
        while True:
            inp=input(">>:").strip()
            cmds=inp.split()
            if hasattr(self,cmds[0]):
                func=getattr(self,cmds[0])
                func(cmds)
    def get(self,cmds):
        print("get......",cmds)
    def put(self,cmds):
        print("put......",cmds)
obj=service()
obj.run()