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我目前正在研究一個Golang Google App Engine項目，並遇到一個小問題。我有一個數據庫「派對」與表「派對」。問題是，當執行下面的代碼時，會打印一個EMPTY json數組 - 它實際上很長，但它只包含空的締約方。 （我在我的數據庫條目）go mysql返回空值
Go代碼（不是全部）：
func getParties(w http.ResponseWriter, r *http.Request) {
rows := getRowsFromSql("select * from parties;")
parties := scanForParties(rows)
json, _ := json.Marshal(parties)
fmt.Fprint(w, string(json))
}
func scanForParties(rows *sql.Rows) []Party {
var parties []Party
for rows.Next() {
var id int
var name, author, datetime, datetime_to, host, location, description, longtitude, latitude, primary_image_id string
rows.Scan(&id, &name, &author, &datetime, &datetime_to, &host, &location, &description, &longtitude, &latitude, &primary_image_id)
party := Party{
Id: id,
Name: name,
Author: author,
Datetime: datetime,
Datetime_to: datetime_to,
Host: host,
Location: location,
Description: description,
Longtitude: longtitude,
Latitude: latitude,
PrimaryImgId: primary_image_id,
}
parties = append(parties, party)
}
return parties
}
func getRowsFromSql(query string) *sql.Rows {
con, err := sql.Open("mysql", dbConnectString)
if err != nil {
panic(err)
}
defer con.Close()
rows, err2 := con.Query(query)
if err != nil {
panic(err2)
}
return rows
}
type Party struct {
Id int
Name string
Author string
Datetime string
Datetime_to string
Host string
Location string
Description string
Longtitude string
Latitude string
PrimaryImgId string
}
而我的當事人表：
mysql> describe parties;
+------------------+----------------+------+-----+-------------------+-----------------------------+
| Field | Type | Null | Key | Default | Extra |
+------------------+----------------+------+-----+-------------------+-----------------------------+
| id | int(11) | NO | PRI | NULL | auto_increment |
| name | varchar(64) | NO | | | |
| author | varchar(64) | YES | | NULL | |
| datetime | datetime | YES | | NULL | |
| last_edited | timestamp | NO | | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| datetime_to | datetime | YES | | NULL | |
| host | text | YES | | NULL | |
| location | text | YES | | NULL | |
| description | text | YES | | NULL | |
| longitude | decimal(23,20) | YES | | NULL | |
| latitude | decimal(23,20) | YES | | NULL | |
| primary_image_id | varchar(256) | YES | | NULL | |
+------------------+----------------+------+-----+-------------------+-----------------------------+
然而，舊版本的代碼作品就好：
func getParties(w http.ResponseWriter, r *http.Request) {
con, dbErr := sql.Open("mysql", dbConnectString)
defer con.Close()
if dbErr == nil {
rows, _ := con.Query("select id, name, author, datetime from parties where datetime >= NOW();")
var parties []Party
var id int
var name string
var author string
var datetime string
for rows.Next() {
rows.Scan(&id, &name, &author, &datetime)
party := Party{}
party.Id = id
party.Name = name
party.Author = author
party.Datetime = datetime
parties = append(parties, party)
}
if len(parties) > 0 {
json, _ := json.Marshal(parties)
fmt.Fprint(w, string(json))
} else {
fmt.Fprint(w, "{}")
}
} else {
fmt.Fprint(w, "{\"Error\"}")
}
}
任何想法爲什麼會發生這種情況？ 感謝提前:)
**從不**忽略'錯誤'返回！海事組織甚至不值得看這個，直到你至少添加了最少的錯誤檢查。 – 2015-04-01 18:00:54
是否有任何被忽略的錯誤，除了解析json時可能出現的錯誤（這不是問題 - 相信我，我檢查過）？ – 2015-04-01 18:03:10
你檢查一次也許。如果沒有在代碼中檢查，沒有人（甚至你）知道現在沒有發生一些錯誤。 – 2015-04-01 18:04:13