1.接口会自动和拥有相同方法的结构体关联

/*
只要一个变量，含有接口类型中的所有方法，那么这个变量就实现这个接口。
如果一个变量含有了多个interface类型的方法，那么这个变量就实现了多个接口。
*/
type MyInterface interface{GetName() stringGetAge() int
}type StringInterface interface{SumAgeSa() int
}type CommonInterface interface{MyInterfaceStringInterfaceGetGender() string
}type Employee struct {name   stringage    intsalary intgender string
}func (self *Employee) GetName() string {return self.name
}func (self *Employee) GetAge() int {return self.age
}func (self *Employee) SumAgeSa() int {return self.age + self.salary
}func (self *Employee) GetGender() string {return self.gender
}/*自动关联上了*/
func IntRun()  {// 空接口的使用，空接口类型的变量可以保存任何类型的值// 空格口类型的变量非常类似于弱类型语言中的变量var varEmptyInterface interface{}fmt.Println("varEmptyInterface is of type %T\n", varEmptyInterface)varEmptyInterface = 100y := varEmptyInterface.(int) //这里可以类型转换（类型断言 ）fmt.Println("varEmptyInterface is of type int", varEmptyInterface, y)varEmptyInterface = "Golang"k, err := varEmptyInterface.(string) //待判断的类型转换（类型断言 ）if err {fmt.Println("varEmptyInterface is of type string", varEmptyInterface, k)}varEmployee := Employee{name:   "Jack Ma",age:    50,salary: 100000000,gender: "Male",}var mm MyInterface = &varEmployeefmt.Println(mm.GetName())fmt.Println(mm.GetAge())//这里可以调用组合内的所有接口var ww CommonInterface = &varEmployeefmt.Println(ww.GetAge(), ww.GetGender(), ww.GetName(), ww.SumAgeSa())
}

2.通过类型获取值

func IntRun()  {var varEmptyInterface interface{}varEmptyInterface = 100y := varEmptyInterface.(int) //这里可以类型转换（类型断言 ）fmt.Println("varEmptyInterface is of type int", varEmptyInterface, y)classifier(varEmptyInterface)}/*
通过类型获取值
*/
func classifier(items ...interface{}) {for i, x := range items {switch x.(type) {case bool:fmt.Println("classifier", "bool", i, x)case float64:fmt.Println("classifier","float64", i, x)case int, int64:fmt.Println("classifier","int", i, x)case nil:fmt.Println("classifier","nil", i, x)case string:fmt.Println("classifier","string", i, x)default:fmt.Println("classifier","other", i, x)}}
}

3.简单工厂

/*
简单工厂例子
*/
type Animal interface {Sleep()Age() intType() string
}type Cat struct {MaxAge int
}func (this *Cat) Sleep() {fmt.Println("Cat need sleep")
}
func (this *Cat) Age() int {return this.MaxAge
}
func (this *Cat) Type() string {return "Cat"
}type Dog struct {MaxAge int
}func (this *Dog) Sleep() {fmt.Println("Dog need sleep")
}
func (this *Dog) Age() int {return this.MaxAge
}
func (this *Dog) Type() string {return "Dog"
}func Factory(name string) Animal {switch name {case "dog":return &Dog{MaxAge: 20}case "cat":return &Cat{MaxAge: 10}default:panic("No such animal")}
}