Go学习笔记(二) | 我对 recover 的一点误解

Recover is a built-in function that regains control of a panicking goroutine. Recover is only useful inside deferred functions. During normal execution, a call to recover will return nil and have no other effect. If the current goroutine is panicking, a call to recover will capture the value given to panic and resume normal execution.

package main

import (
	"fmt"
	"log"
	"time"
)

func main() {

	ch := make(chan int, 10)

	for i := 2; i > 0; i-- {
		go func(i int) {
			defer func() {
				err := recover()
				if err != nil {
					log.Println(err)
				}
			}()
			for val := range ch {
				fmt.Println("---->", val, "Go", i)
				if val%2 == 1 && i == 1 {
					panic("BOOM BOOM")
				}
				time.Sleep(2 * time.Second)
			}
		}(i)
	}

	var i int
	for {
		ch <- i
		time.Sleep(1 * time.Second)
		fmt.Println(i, "<---")
		i++
	}
}

$ go run recover.go
----> 0 Go 2
0 <---
----> 1 Go 1
2018/01/21 21:52:54 BOOM BOOM
1 <---
----> 2 Go 2
2 <---
3 <---
----> 3 Go 2
4 <---
----> 4 Go 2
5 <---
6 <---
----> 5 Go 2
7 <---
8 <---
----> 6 Go 2
...