Golang method | Interfaces 示例

方法与接口(method Interface)

 

package goroutine

import (
	"fmt"
	"log"
)

// manager Appstore online account

type Account struct {
	surName   string
	givenName string
}

// 方法的调用 如果需要对调用对象做修改操作，则需要使用 `*` 引用其指针创建方法。
func (a *Account) ChangeName() {
	fmt.Printf("old surname:%s, givenName:%s\n", a.surName, a.givenName)
	log.SetPrefix("ChangeName(): ")
	var (
		surName   string
		givenName string
	)

	fmt.Printf("Input New surName:\t ")
	_, err := fmt.Scanf("%s\n", &surName)
	// 值得注意的是，在使用Scanf进行键盘接收时，需要接收掉末尾的\n
	if err != nil {
		log.Fatalf("surName error:%v", err)
	}
	fmt.Printf("input new givenName:\t")
	_, err = fmt.Scanf("%s", &givenName)
	if err != nil {
		log.Fatalf("givenName error:%v", err)
	}
	a.surName = surName
	a.givenName = givenName
}

结构/方法的声明

type Employee struct {
    loanLimit float32
    Account
    // 声明时: Account: Account{columnName: value1, columnName2: value2}
}

func (e *Employee) AddCredits(v float32) {
	e.loanLimit += v
}

func (e *Employee) RemoveCredits(v float32) {
	e.loanLimit -= v
	if e.loanLimit < 0 {
		e.loanLimit = 0
	}
}
func (e Employee) CheckCredits() {
	fmt.Println(e)
}

// 重写fmt.Println()调用的String()方法，其实标准打印Employee对象。
func (e Employee) String() string {
	return fmt.Sprintf("Name: %s %s Credits:%5.2f", e.surName, e.givenName, e.loanLimit)
}

// 声明一个EmployeeTools的接口，服务于Employee类型对象
type EmployeeTools interface {
	ChangeName()
	AddCredits(v float32)
	RemoveCredits(v float32)
	CheckCredits()
}

func createEmployee(surname, givenName string) Employee {
	var e2 *Employee = new(Employee)  
    // new()方法生成一个指定数据类型的对象，返回其指针
	e2.surName, e2.givenName = surname, givenName
	return *e2
}

接口的使用

func EmployeeMethod() {
	var Students []Employee
	var namelist map[string]string = map[string]string{
		"Tom":  "meh",
		"Jeck": "marh",
		"John": "Mark",
	}
    // 使用for循环结合 createEmployee()函数批量生成
	for firstName, LastName := range namelist {
		Students = append(Students, createEmployee(firstName, LastName))
	}
    
	Students[0].ChangeName()
	Students[0].AddCredits(12.2)
	//Students[0].CheckCredits()

	for _, info := range Students {
		fmt.Println(info)
	}

}