自定义 Error

+package common
+
+import "fmt"
+
+type Error struct {
+	Code int
+	err error
+}
+
+func (e Error)Error()string{
+	if e.err==nil{
+		return ""
+	}
+	return e.err.Error()
+}
+
+func NewError(code int,e error)Error{
+	return Error{
+		Code:code,
+		err:e,
+	}
+}
+
+func NewErrorWithMsg(code int,msg string)Error{
+	return NewError(code,fmt.Errorf(msg))
+}

+package common
+
+import (
+	"fmt"
+	"testing"
+)
+
+func Test_Error(t *testing.T){
+	e :=NewError(1,fmt.Errorf("%v","some error"))
+	t.Log(e,e.Code)
+	t.Logf("%s",e)
+
+	emsg :=NewErrorWithMsg(2,"some error")
+	t.Log(emsg,emsg.Code)
+}