Golang之定义错误（errors）

基本示例：

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)
}

错误处理：

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()
}