接口
1.接口定义
package main
import "fmt"
//定义接口类型
type Humaner interface {
sayHi()
}
type Student struct {
name string
id int
}
func (stu *Student) sayHi() {
fmt.Printf("Student[%s,%d] sayHi\n", stu.name, stu.id)
}
type Teacher struct {
addr string
group string
}
func (teacher *Teacher) sayHi() {
fmt.Printf("Teacher[%s,%s] sayHi\n", teacher.addr, teacher.group)
}
type Mystr string
func (str *Mystr) sayHi() {
fmt.Printf("Mystr[%s] sayHi\n", *str)
}
func main() {
var human Humaner
s := &Student{"tony", 77}
human = s
human.sayHi()
t := &Teacher{"tom", "go"}
human = t
human.sayHi()
var str Mystr = "Hello Tony"
human = &str
human.sayHi()
}
Student[tony,77] sayHi
Teacher[tom,go] sayHi
Mystr[Hello Tony] sayHi
2.多态
package main
import "fmt"
//定义接口类型
type Humaner interface {
sayHi()
}
type Student struct {
name string
id int
}
func (stu *Student) sayHi() {
fmt.Printf("Student[%s,%d] sayHi\n", stu.name, stu.id)
}
type Teacher struct {
addr string
group string
}
func (teacher *Teacher) sayHi() {
fmt.Printf("Teacher[%s,%s] sayHi\n", teacher.addr, teacher.group)
}
type Mystr string
func (str *Mystr) sayHi() {
fmt.Printf("Mystr[%s] sayHi\n", *str)
}
//定义一个普通函数，函数的参数为接口类型
//只有一个函数，可以有不同的表现，多态
func WhoSayHi(humaner Humaner) {
humaner.sayHi()
}
func main() {
s := &Student{"tony", 77}
t := &Teacher{"tom", "go"}
var str Mystr = "Hello Tony"
//调用同一个函数，不同的表现
WhoSayHi(s)
WhoSayHi(t)
WhoSayHi(&str)
//创建一个切片
x := make([]Humaner, 3)
x[0] = s
x[1] = t
x[2] = &str
fmt.Println("------------------------")
//第一个返回下标，第二个返回下标所对应的值
for _, i := range x {
i.sayHi()
}
}
Student[tony,77] sayHi
Teacher[tom,go] sayHi
Mystr[Hello Tony] sayHi
------------------------
Student[tony,77] sayHi
Teacher[tom,go] sayHi
Mystr[Hello Tony] sayHi
3.接口的继承
package main
import "fmt"
//定义接口类型
type Humaner interface { //子集
sayHi()
}
type Personer interface { //超集
Humaner //匿名字段，继承sayHi()
sing(lrc string)
}
type Student struct {
name string
id int
}
//Student实现了sayHi
func (stu *Student) sayHi() {
fmt.Printf("Student[%s,%d] sayHi\n", stu.name, stu.id)
}
func (tmp *Student) sing(lrc string) {
fmt.Println("Student在唱着：", lrc)
}
func main() {
var i Personer
s := &Student{"Tony", 66}
i = s
i.sayHi()
i.sing("好汉歌")
}
Student[Tony,66] sayHi
Student在唱着： 好汉歌
4.接口转换
package main
import "fmt"
//定义接口类型
type Humaner interface {
sayHi()
}
type Personer interface {
Humaner //匿名字段，继承sayHi()
sing(lrc string)
}
type Student struct {
name string
id int
}
//Student实现了sayHi
func (stu *Student) sayHi() {
fmt.Printf("Student[%s,%d] sayHi\n", stu.name, stu.id)
}
func (tmp *Student) sing(lrc string) {
fmt.Println("Student在唱着：", lrc)
}
func main() {
//超集可以转换成子集，反过来不可以
var iPro Personer
iPro = &Student{"mike", 777}
var i Humaner
//iPro = i //err
i = iPro
i.sayHi()
}
Student[mike,777] sayHi
5.空接口
package main
import "fmt"
//定义这样的方法可以
func xxx(arg ...interface{}) {
}
func main() {
//空接口万能类型，保存任意类型的值
var i interface{} = 1
fmt.Println("i = ", i)
i = "abc"
fmt.Println("i = ", i)
}
i = 1
i = abc
6.类型判断之断言
package main
import "fmt"
type Cat struct {
name string
id int
}
func main() {
i := make([]interface{}, 3)
i[0] = 1
i[1] = "hello go"
i[2] = Cat{"tom", 3}
for index, data := range i {
if value, ok := data.(int); ok == true {
fmt.Printf("x[%d] 类型为int,内容为%d\n", index, value)
} else if value, ok := data.(string); ok == true {
fmt.Printf("x[%d] 类型为string,内容为%s\n", index, value)
} else if value, ok := data.(Cat); ok == true {
fmt.Printf("x[%d] 类型为Cat,name = %s,id =%d\n ", index, value.name, value.id)
}
}
}
x[0] 类型为int,内容为1
x[1] 类型为string,内容为hello go
x[2] 类型为Cat,name = tom,id =3
7.类型判断之switch
package main
import "fmt"
type Cat struct {
name string
id int
}
func main() {
i := make([]interface{}, 3)
i[0] = 1
i[1] = "hello go"
i[2] = Cat{"tom", 3}
for index, data := range i {
switch value:=data.(type) {
case int:
fmt.Printf("x[%d] 类型为int,内容为%d\n", index, value)
case string:
fmt.Printf("x[%d] 类型为string,内容为%s\n", index, value)
case Cat:
fmt.Printf("x[%d] 类型为Cat,name = %s,id =%d\n ", index, value.name, value.id)
}
}
}
x[0] 类型为int,内容为1
x[1] 类型为string,内容为hello go
x[2] 类型为Cat,name = tom,id =3
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