解析PostgreSQL TIMESTAMP类型的值时出现问题 [英] Problem parsing values of PostgreSQL TIMESTAMP type
问题描述
在PostgreSQL中,我有一个名为 surveys
的表.
In PostgreSQL, I have table called surveys
.
CREATE TABLE SURVEYS(
SURVEY_ID UUID PRIMARY KEY NOT NULL DEFAULT uuid_generate_v4(),
SURVEY_NAME VARCHAR NOT NULL,
SURVEY_DESCRIPTION TEXT,
START_PERIOD TIMESTAMP,
END_PERIOD TIMESTAMP
);
您只能看到 SURVEY_ID
和 SURVEY_NAME
列是 NOT NULL
.
在Go中,我想通过 POST
请求在该表中创建新条目.我发送这样的JSON对象:
In Go, I want to create new entry in that table by POST
request. I send JSON object like this:
{
"survey_name": "NAME",
"survey_description": "DESCRIPTION",
"start_period": "2019-01-01 00:00:00",
"end_period": "2019-02-28 23:59:59"
}
不幸的是,它引发了奇怪的错误:
Unfortunatly it raise strange ERROR:
parsing time ""2019-01-01 00:00:00"" as ""2006-01-02T15:04:05Z07:00"": cannot parse " 00:00:00"" as "T"
我在哪里犯错误以及如何解决我的问题?
Where I make mistake and how to fix my problem?
models/surveys.go:
import (
"database/sql"
"time"
)
type NullTime struct {
time.Time
Valid bool
}
type Survey struct {
ID int `json:"survey_id"`
Name string `json:"survey_name"`
Description sql.NullString `json:"survey_description"`
StartPeriod NullTime `json:"start_period"`
EndPeriod NullTime `json:"end_period"`
}
controllers/surveys.go:
var CreateSurvey = func(responseWriter http.ResponseWriter, request *http.Request) {
// Initialize variables.
survey := models.Survey{}
var err error
// The decoder introduces its own buffering and may read data from argument beyond the JSON values requested.
err = json.NewDecoder(request.Body).Decode(&survey)
if err != nil {
log.Println(err)
utils.ResponseWithError(responseWriter, http.StatusInternalServerError, err.Error())
return
}
defer request.Body.Close()
// Execute INSERT SQL statement.
_, err = database.DB.Exec("INSERT INTO surveys (survey_name, survey_description, start_period, end_period) VALUES ($1, $2, $3, $4);", survey.Name, survey.Description, survey.StartPeriod, survey.EndPeriod)
// Shape the response depending on the result of the previous command.
if err != nil {
log.Println(err)
utils.ResponseWithError(responseWriter, http.StatusInternalServerError, err.Error())
return
}
utils.ResponseWithSuccess(responseWriter, http.StatusCreated, "The new entry successfully created.")
}
推荐答案
该错误已经说明了错误所在:
The error already says what is wrong:
解析时间""2019-01-01 00:00:00"如"2006-01-02T15:04:05Z07:00":无法解析"00:00:00"为"T"
parsing time ""2019-01-01 00:00:00"" as ""2006-01-02T15:04:05Z07:00"": cannot parse " 00:00:00"" as "T"
您传递的是" 2019-01-01 00:00:00"
,而它期望使用不同的时间格式,即 UnmarshalJSON的默认).
You are passing "2019-01-01 00:00:00"
while it expects a different time format, namely RFC3339 (UnmarshalJSON's default).
要解决此问题,您要么希望以期望的格式传递时间"2019-01-01T00:00:00Z00:00"
,要么定义自己的类型 CustomTime 像这样的代码:
To solve this, you either want to pass the time in the expected format "2019-01-01T00:00:00Z00:00"
or define your own type CustomTime
like this:
const timeFormat = "2006-01-02 15:04:05"
type CustomTime time.Time
func (ct *CustomTime) UnmarshalJSON(data []byte) error {
newTime, err := time.Parse(timeFormat, strings.Trim(string(data), "\""))
if err != nil {
return err
}
*ct = CustomTime(newTime)
return nil
}
func (ct *CustomTime) MarshalJSON() ([]byte, error) {
return []byte(fmt.Sprintf("%q", time.Time(*ct).Format(timeFormat))), nil
}
小心,您可能还需要实现 Valuer
和 Scanner
接口,以便在数据库中进行解析和解析,如下所示:/p>
Careful, you might also need to implement the Valuer
and the Scanner
interfaces for the time to be parsed in and out of the database, something like the following:
func (ct CustomTime) Value() (driver.Value, error) {
return time.Time(ct), nil
}
func (ct *CustomTime) Scan(src interface{}) error {
if val, ok := src.(time.Time); ok {
*ct = CustomTime(val)
} else {
return errors.New("time Scanner passed a non-time object")
}
return nil
}
进入游乐场示例.
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