golang的defer,recover,panic用法

示例如下:

package main

import (
    "fmt"
)

func defer_call() {
    defer func() {
        fmt.Println("before")
    }()

    defer func() {
        if p := recover(); p != nil {
            fmt.Println("normal panic")
        } else {
            fmt.Println("no panic")
        }
    }()

    defer func() {
        fmt.Println("after")
    }()

    panic("panic")

    fmt.Println("come on")
}

func main() {
    defer_call()
}
           

输出:

after

normal panic

before

defer按照先进后出的原则执行.

recover()截获了panic()的行为, recover()返回的值不为nil. 否则为空.

由于触发了panic, 字符串”come on”没有被输出.