Golang泛型中关键词【any】表示任意类型;

官方文档：tip.golang.org/ref/spec#Ty…

基本款

1. Java版

public class Point<T> {
    private T x;
    public void setX(T x) {
        this.x = x;
    }
    public T getX() {
        return this.x;
    }

    public static void main(String[] args) {
        Point<Integer> pointInt = new Point<>();
        pointInt.setX(100);
        System.out.println("Integer x=" + pointInt.getX());

        Point<String> pointStr = new Point<>();
        pointStr.setX("字符串");
        System.out.println("String x=" + pointStr.getX());
    }
}

标准输出：

Integer x=100
String x=字符串

1. Golang版

package main

import "fmt"

type Point[T any] struct {
   x T
}

func (n Point[T]) GetX() T {
   return n.x
}
func main() {
   pointInt := Point[int]{}
   pointInt.x = 100
   fmt.Printf("int x=%d\n", pointInt.GetX())

   pointStr := Point[string]{}
   pointStr.x = "字符串"
   fmt.Printf("string x=%s\n", pointStr.GetX())
}

标准输出：

int x=100
string x=字符串

---

1.1 Java版多参数泛型

public class Point<T, O> {
    private T x;
    private O y;
    public void setX(T x) {
        this.x = x;
    }
    public T getX() {
        return this.x;
    }
    public void setY(O y) {
        this.y = y;
    }
    public O getY() {
        return this.y;
    }
    public static void main(String[] args) {
        Point<Integer, String> point = new Point<>();
        point.setX(100);
        point.setY("字符串");

        System.out.println("Integer x=" + point.getX() + ", String y=" + point.getY());
    }
}

标准输出：

Integer x=100, String y=字符串

1.1 Golang版多参数泛型

import (
	"fmt"
)

type Point[T any, O any] struct {
	x T
	y O
}
func (n Point[T, O]) GetX() T {
	return n.x
}
func (n Point[T, O]) GetY() O {
	return n.y
}
func main() {
	point := Point[int, string]{}
	point.x = 100
	point.y = "字符串"
	fmt.Printf("int x=%d, string y=%s\n", point.GetX(), point.GetY())
}

标准输出：

int x=100, string y=字符串

---

---

类型约束 <? extends T> 上界通配符（Upper Bounds Wildcards）

2. Java版

public class Point<T extends Number> {
    private T x;
    public void setX(T x) {
        this.x = x;
    }
    public T getX() {
        return this.x;
    }

    public static void main(String[] args) {
        Point<Integer> pointInt = new Point<>();
        pointInt.setX(100);
        System.out.println("Integer x=" + pointInt.getX());

        Point<Float> pointStr = new Point<>();
        pointStr.setX(1.8f);
        System.out.println("Float x=" + pointStr.getX());
        
        if (pointInt.getClass() == pointFloat.getClass()) {
            // 结果为相同类型
            System.out.println("相同类型");
        }
    }
}

标准输出：

Integer x=100
Float x=1.8
相同类型

2. Golang版

import (
   "fmt"
   "reflect"
)

type Number interface {
   int | int32 | float32 | float64
}

type Point[T Number] struct {
   x T
}
func (n Point[T]) GetX() T {
   return n.x
}
func main() {
   pointInt := Point[int]{}
   pointInt.x = 100
   fmt.Printf("int x=%d\n", pointInt.GetX())

   pointFloat := Point[float32]{}
   pointFloat.x = 1.8
   fmt.Printf("float32 x=%f\n", pointFloat.GetX())

   if reflect.TypeOf(pointInt) == reflect.TypeOf(pointFloat) {
      fmt.Println("相同类型")
   } else {
      // 结果为 不同类型
      fmt.Println("不同类型")
   }
}

标准输出：

int x=100
float32 x=1.800000
不同类型