我对 golang 很陌生,但仍在为很多事情而苦苦挣扎。
当实现像这样的自定义类型时type Date time.Time,定义一种方法来编组/解组"2006-01-02"格式的日期(来自 JSON 文件和 POST API 请求),日期存储在结构中的最终方式是:
{wall:0 ext:63776764800 loc:<nil>}
有人可以帮助我理解为什么这种格式(而不是常规格式time.Time)因为自定义类型Date是大写的,因此被导出了吗?
这是一个实现(链接到代码下方的游乐场):
package main
import (
"encoding/json"
"fmt"
"log"
"time"
)
const sample = `{
"ID": "1",
"ticker": "S30J2",
"issueDate": "2022-01-31",
"maturity": "2023-06-30",
"coupon": 0,
"cashFlow": [
{ "date": "2022-06-30",
"rate": 0,
"amortization": 1,
"residual": 0,
"amount": 50},
{
"date": "2023-06-30",
"rate": 0,
"amortization": 1,
"residual": 0,
"amount": 50}
]
}`
type Date time.Time
func (d Date) MarshalJSON() ([]byte, error) {
return []byte(time.Time(d).Format("2006-1-2")), nil
}
func (d *Date) UnmarshalJSON(b []byte) error {
// Disregard leading and trailing "
t, err := time.Parse("2006-1-2", string(b[1:len(b)-2]))
if err != nil {
return err
}
*d = Date(t)
return nil
}
type Flujo struct {
Date Date
Rate float64
Amort float64
Residual float64
Amount float64
}
type Bond struct {
ID string
Ticker string
IssueDate Date
Maturity Date
Coupon float64
Cashflow []Flujo
}
func main() {
var b Bond
if err := json.Unmarshal([]byte(sample), &b); err != nil {
log.Fatalf("%s", err)
}
fmt.Printf("%+v\n", b.IssueDate)
// I need to wrap it via Format.
fmt.Println("Fecha: ", time.Time(b.IssueDate).Format("2006-01-02"))
}
这里的工作示例:https ://go.dev/play/p/YddzXA9PQdP
感谢您的帮助和理解。
慕勒3428872