package main
//定义错误
//error 也是个接口
import (
"errors"
"fmt"
)
var errNotFound error = errors.New("Not found error")
func main() {
fmt.Printf("error:%v", errNotFound)
}
package main
import (
"fmt"
"os"
"time"
)
type PathError struct {
path string
op string
createTime string
message string
}
func (p *PathError) Error() string {
return fmt.Sprintf("path=%s op=%s createTime=%s message=%s",
p.path, p.op, p.createTime, p.message)
}
func Open(filename string) error {
file, err := os.Open(filename)
if err != nil {
return &PathError{
path: filename,
op: "read",
message: err.Error(),
createTime: fmt.Sprintf("%v", time.Now()),
}
}
defer file.Close()
return nil
}
func main() {
err := Open("D:/project/src/go_dev/day7/example10/123.txt")
switch v := err.(type) {
case *PathError:
fmt.Println("get path error,", v)
default:
}
}
练习
package main
import "fmt"
func badCall() {
panic("bad end")
}
func test() {
defer func() {
if e := recover(); e != nil {
fmt.Printf("Panicking%s\r\n", e)
}
}()
badCall()
fmt.Printf("After bad call\r\n")
}
func main() {
fmt.Printf("Calling test\r\n")
test()
}