关于Go语言中特有的设计模式与实现方式讲解

package main

import (
	"fmt"
	"sync"
)

type Singleton struct {
	Name string
}

var instance *Singleton
var once sync.Once

func GetInstance() *Singleton {
	once.Do(func() {
		instance = &Singleton{Name: "Singleton Instance"}
	})
	return instance
}

func main() {
	s := GetInstance()
	fmt.Println(s.Name)
}

package main

import "fmt"

type Animal interface {
	Sound() string
}

type Dog struct{}

func (d Dog) Sound() string {
	return "Woof!"
}

type Cat struct{}

func (c Cat) Sound() string {
	return "Meow!"
}

func AnimalFactory(animalType string) Animal {
	switch animalType {
	case "dog":
		return Dog{}
	case "cat":
		return Cat{}
	default:
		return nil
	}
}

func main() {
	dog := AnimalFactory("dog")
	cat := AnimalFactory("cat")

	fmt.Println(dog.Sound()) // Output: Woof!
	fmt.Println(cat.Sound()) // Output: Meow!
}

package main

import (
	"fmt"
	"time"
)

func worker(id int, jobs <-chan int, results chan<- int) {
	for j := range jobs {
		fmt.Printf("Worker %d started job %d\n", id, j)
		time.Sleep(time.Second)
		fmt.Printf("Worker %d finished job %d\n", id, j)
		results <- j * 2
	}
}

func main() {
	jobs := make(chan int, 5)
	results := make(chan int, 5)

	// 启动3个协程
	for i := 1; i <= 3; i++ {
		go worker(i, jobs, results)
	}

	// 发送5个任务到管道
	for j := 1; j <= 5; j++ {
		jobs <- j
	}
	close(jobs)

	// 输出结果
	for r := 1; r <= 5; r++ {
		fmt.Println(<-results)
	}
}