Go语言之Interface(二)
使用指针接收器和值接收器实现接口
type Describer interface {
Describe()
}
type Person struct {
name string
age int
}
func (p Person) Describe() {
fmt.Printf("%s is %d years old\n", p.name, p.age)
}
type Address struct {
state string
country string
}
func (a *Address) Describe() {
fmt.Printf("State %s Country %s", a.state, a.country)
}
var d1 Describer
p1 := Person{"Sam", 25}
d1 = p1
d1.Describe()
p2 := Person{"James", 39}
d1 = &p2
d1.Describe()
var d2 Describer
a := Address{"Beijing", "China"}
d2 = &a
d2.Describe()
实现多个接口
type NormalSalary interface {
DisplaySalary()
}
type LevaeSalary interface {
CalculateLeaveLeft() int
}
type Employee struct {
firstName string
lastName string
basicPay int
pf int
totalLeaves int
leavesTaken int
}
func (e Employee) DisplaySalary() {
fmt.Printf("%s %s has salary $%d\n", e.firstName, e.lastName, (e.basicPay + e.pf))
}
func (e Employee) CalculateLeaveLeft() int {
return e.totalLeaves - e.leavesTaken
}
e := Employee{
firstName: "Kevin",
lastName: "Lee",
basicPay: 5000,
pf: 200,
totalLeaves: 30,
leavesTaken: 5,
}
var ns NormalSalary = e
ns.DisplaySalary()
var l LevaeSalary = e
fmt.Println("Leaves left =", l.CalculateLeaveLeft())
接口嵌套
在Go
语言中没有继承的概念,但是通过组合可以实现继承的效果
type NormalSalary interface {
DisplaySalary()
}
type LevaeSalary interface {
CalculateLeaveLeft() int
}
type SalaryOperator interface {
NormalSalary
LevaeSalary
}
var empOp SalaryOperator = e
empOp.DisplaySalary()
fmt.Println("Leaves left = ", empOp.CalculateLeaveLeft())
接口零值
零值接口是nil
,nil
接口中的type
和value
都是nil
type Describer interface {
Describe()
}
var d4 Describer
if d4 == nil {
fmt.Printf("d4 is nil and has type %T value %v\n", d4, d4)
}
输出结果是
d4 is nil and has type <nil> value <nil>
不要让懒惰占据你的大脑,不让要妥协拖跨你的人生。青春就是一张票,能不能赶上时代的快车,你的步伐掌握在你的脚下,good luck