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这个话题,本质上和方法的值类型接收者和指针类型接收者的思考方法是一样的,值接收者是一个拷贝,是一个副本,而指针接收者,传递的是指针

实例演示

定义一个Pet接口

type Pet interface {
    eat()
}

定义一个Dog结构体

type Dog struct {
    name string
}

实现Pet接口(接收者是值类型)

func (dog Dog) eat() {
    fmt.Printf("dog: %p\n", &dog)
    fmt.Println("dog eat...")
    dog.name = "黑黑"
}

测试

package main

import "fmt"

type Pet interface {
    eat()
}

type Dog struct {
    name string
}

func (dog Dog) eat() {
    fmt.Printf("dog: %p\n", &dog)
    fmt.Println("dog eat...")
    dog.name = "黑黑"
}

func main() {
    dog := Dog{name: "花花"}
    fmt.Printf("dog: %p\n", &dog)
    dog.eat()
    fmt.Printf("dog: %v\n", dog)
}

运行结果

[Running] go run "d:\SynologyDrive\软件开发\go\golang入门到项目实战\goproject\360duote.com\pro01\tempCodeRunnerFile.go"
dog: 0xc000050230
dog: 0xc000050240
dog eat...
dog: {花花}

从运行结果,我们看出dog的地址变了,说明是复制了一份,dog的name没有变说明外面的dog变量没有被改变。

将Pet接口改为指针接收者

package main

import "fmt"

type Pet interface {
    eat()
}

type Dog struct {
    name string
}

func (dog *Dog) eat() {
    fmt.Printf("dog: %p\n", dog)
    fmt.Println("dog eat...")
    dog.name = "黑黑"
}

func main() {
    dog := &Dog{name: "花花"}
    fmt.Printf("dog: %p\n", dog)
    dog.eat()
    fmt.Printf("dog: %v\n", dog)
}

运行结果

[Running] go run "d:\SynologyDrive\软件开发\go\golang入门到项目实战\goproject\360duote.com\pro01\test.go"
dog: 0xc000050230
dog: 0xc000050230
dog eat...
dog: &{黑黑}