使用包
package main
import (
"errors"
"fmt"
)
error
//error
func f1(arg int) (int, error) {
if arg == 42 {
return -1, errors.New("can't work with 42")
}
return arg + 3 , nil
}
// 自定义的error
type argError struct {
arg int
prob string
}
/**
自定义的错误，就是实现系统的内置的这个接口
type error interface {
Error() string
}
*/
func (e argError) Error() string { //实现接口
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)
}
}
fmt.Println("=========")
_, e := f2(42)
/**
把实现类输入error,获得属性
e.(argError)
*/
if ae,ok := e.(argError); ok {
fmt.Println("ok: ", ok)
fmt.Println("arg: ", ae.arg)
fmt.Println("prob: ", ae.prob)
}
}
并发--Goroutines
// Goroutines
func f(from string){
for i := 0; i < 50; i++ {
fmt.Println(from,i)
}
}
func main(){
fmt.Println("-----goroutines------")
f("direct")
// 使用go下面两个方法在不同线程异步执行
go f("goroutine")
go func(msg string) {
fmt.Println(msg)
}("going")
fmt.Scanln()
fmt.Println("done")
}
