goroutine

goroutine

协程（goroutine）是轻量级的执行线程

• 主线程结束协程自动结束，主线程不会等待协程的结束

package main

import (
  "fmt"
  "time"
)

func f(from string) {
  for i := 0; i < 3; i++ {
    fmt.Println(from, ":", i)
  }
}

func main() {
  f("direct")

  // 创建一个 goroutine
  go f("goroutine")

  // 创建一个匿名 goroutine
  go func(msg string) {
    fmt.Println(msg)
  }("going")

  time.Sleep(time.Second)
  fmt.Println("done")

// direct : 0
// direct : 1
// direct : 2
// going
// goroutine : 0
// goroutine : 1
// goroutine : 2
// done
}

package main

import (
  "fmt"
  "sync"
  "time"
)

var wait = sync.WaitGroup{}

func study() {
  time.Sleep(2 * time.Second)
  fmt.Println("去学习")
}

func swim() {
  time.Sleep(3 * time.Second)
  fmt.Println("去游泳")
  wait.Done()
}

func main() {
  t1 := time.Now()
  wait.Add(1)
  go swim()
  study()
  wait.Wait()
  t2 := time.Now()
  fmt.Println("总耗时：", t2.Sub(t1))
}