Interfaces

Go编程提供了另一种称为interfaces数据类型，它代表一组方法签名。 struct数据类型实现这些接口以具有接口的方法签名的方法定义。

语法 (Syntax)

/* define an interface */
type interface_name interface {
   method_name1 [return_type]
   method_name2 [return_type]
   method_name3 [return_type]
   ...
   method_namen [return_type]
}
/* define a struct */
type struct_name struct {
   /* variables */
}
/* implement interface methods*/
func (struct_name_variable struct_name) method_name1() [return_type] {
   /* method implementation */
}
...
func (struct_name_variable struct_name) method_namen() [return_type] {
   /* method implementation */
}

例子 (Example)

package main
import ("fmt" "math")
/* define an interface */
type Shape interface {
   area() float64
}
/* define a circle */
type Circle struct {
   x,y,radius float64
}
/* define a rectangle */
type Rectangle struct {
   width, height float64
}
/* define a method for circle (implementation of Shape.area())*/
func(circle Circle) area() float64 {
   return math.Pi * circle.radius * circle.radius
}
/* define a method for rectangle (implementation of Shape.area())*/
func(rect Rectangle) area() float64 {
   return rect.width * rect.height
}
/* define a method for shape */
func getArea(shape Shape) float64 {
   return shape.area()
}
func main() {
   circle := Circle{x:0,y:0,radius:5}
   rectangle := Rectangle {width:10, height:5}
   fmt.Printf("Circle area: %f\n",getArea(circle))
   fmt.Printf("Rectangle area: %f\n",getArea(rectangle))
}

编译并执行上述代码时，会产生以下结果 -

Circle area: 78.539816
Rectangle area: 50.000000