Golang 错误及错误处理

错误捕获

package main

import (
    "errors"
    "fmt"
)

func f1(arg int) (int, error) {
    if arg == 42 {

        return -1, errors.New("can't work with 42")

    }

    return arg + 3, nil
}

type argError struct {
    arg  int
    prob string
}

func (e *argError) Error() string {
    return fmt.Sprintf("%d - %s", e.arg, e.prob)
}

func f2(arg int) (int, error) {
    if arg == 42 {

        return -1, &argError{arg, "can't work with it"}
    }
    return arg + 3, nil
}

func main() {

    for _, i := range []int{7, 42} {
        if r, e := f1(i); e != nil {
            fmt.Println("f1 failed:", e)
        } else {
            fmt.Println("f1 worked:", r)
        }
    }
    for _, i := range []int{7, 42} {
        if r, e := f2(i); e != nil {
            fmt.Println("f2 failed:", e)
        } else {
            fmt.Println("f2 worked:", r)
        }
    }

    _, e := f2(42)
    if ae, ok := e.(*argError); ok {
        fmt.Println(ae.arg)
        fmt.Println(ae.prob)
    }
}

运行：

$ go run errors.go
f1 worked: 10
f1 failed: can't work with 42
f2 worked: 10
f2 failed: 42 - can't work with it
42
can't work with it

错误处理

创建error：

func main() {
	defer func() {
		if err := recover(); err != nil {
			fmt.Println(err)
		}
	}()
	fmt.Println("main() started")
	panic("error here.")
	fmt.Println("END main()")
}

参考链接

• err handling go blog: https://go.dev/blog/error-handling-and-go