使用Go语言创建error的几种方式小结

//标准os包下的函数
func Open(name string) (*File, error) {
	return OpenFile(name, O_RDONLY, 0)
}

type error interface {
	Error() string
}

//errors包errors.go文件
type errorString struct {
	s string
}

func (e *errorString) Error() string {
	return e.s
}

package school

import "errors"

type Student struct {
	ID    int
	Name  string
	Score int
}

func NewStudent(id int, name string, score int) (*Student, error) {
	if id <= 0 {
		return nil, errors.New("id could not less than 0")
	}

	if score < 0 || score > 100 {
		return nil, errors.New("score must between 0 and 100")
	}

	return &Student{id, name, score}, nil
}

package school

import (
	"fmt"
)

type Student struct {
	ID    int
	Name  string
	Score int
}

func NewStudent(id int, name string, score int) (*Student, error) {
	if id <= 0 {
		return nil, fmt.Errorf("%d is less than 0", id)
	}

	if score < 0 || score > 100 {
		return nil, fmt.Errorf("%d is not between 0 and 100", score)
	}

	return &Student{id, name, score}, nil
}

package main

import (
	"fmt"
	"net/http"
)

type ResponseError struct {
	code    int
	message string
}

func (r ResponseError) Error() string {
	return fmt.Sprintf(`{"code":%d,"message":"%s"}`, r.code, r.message)
}

func getUser(id string) (map[string]string, error) {
	if len(id) == 0 {
		return nil, &ResponseError{1, "id不能为空"}
	}
	return map[string]string{"id": id, "name": "测试"}, nil
}

func main() {
	http.HandleFunc("/user", func(w http.ResponseWriter, r *http.Request) {
		id := r.FormValue("id")
		user, err := getUser(id)

		if err != nil {
			fmt.Fprint(w, err)
			return
		}
		fmt.Fprint(w, user)
	})
	http.ListenAndServe(":80", nil)
}