英文:
Unable to parse a complex json in golang
问题
{
"period": "yy",
"exec_period": {
"start": {
"month": 1,
"week": 2,
"day": 3,
"hour": 4,
"minute": 5
},
"end": {
"month": 6,
"week": 7,
"day": 8,
"hour": 9,
"minute": 10
}
},
"backup": [
{
"local_dir": "directoryLo1",
"server_dir": "directoryLo2",
"server_host": "domaineName"
},
{
"local_dir": "directoryLo1",
"server_dir": "directorySe2",
"server_host": "domaineName"
}
],
"incremental_save": "1Y2M"
}
英文:
I want to parse this JSON (in config/synch.conf):
{"period" :"yy","exec_period" :{"start" : {"month" : 1,"week" : 2,"day" : 3,"hour" : 4,"minute" : 5},"end" : {"month" : 6,"week" : 7,"day" : 8,"hour" : 9,"minute" : 10}},"backup" : [{"local_dir" : "directoryLo1","server_dir" : "directoryLo2","server_host" : "domaineName"},{"local_dir" : "directoryLo1","server_dir" : "directorySe2","server_host" : "domaineName"}],"incremental_save" : "1Y2M"}
With this programm:
package mainimport ("encoding/json""fmt""io/ioutil")func main() {content, err := ioutil.ReadFile("config/synch.conf")if err == nil {type date struct{month float64week float64day float64hour float64minute float64}type period struct{start dateend date}type backupType []struct{local_dir stringserver_dir stringserver_host string}type jason struct{period stringexec_period periodbackup backupTypeincremental_save string}var parsedMap jasonerr := json.Unmarshal(content, &parsedMap)if err!= nil {fmt.Println(err)}fmt.Println(parsedMap)} else {panic(err)}}
Which doesn't work as expected, as the output is:
{ {{0 0 0 0 0} {0 0 0 0 0}} [] }
Here is the same example at play.golang.org
http://play.golang.org/p/XoMJIDIV59
I don't know if this is possible with go, but I wanted to get the value of the json.Unmarshal function stored in a map[string]interface{} (or another object that allows that) where I could access, for example, the value of the minute's end (10) like this: parsedMap["exec_period"]["end"]["minute"], but I don't uderstand the "Generic JSON withinterface{}" part of [JSON and Go][1] at golang.org
[1]: http://golang.org/doc/articles/json_and_go.html "JSON and Go"
答案1
得分: 13
你的代码很好，除了json包只能处理导出的字段之外。
如果你将每个字段名的首字母大写，一切都会正常工作：
type date struct {Month float64Week float64Day float64Hour float64Minute float64}type period struct {Start dateEnd date}type backupType []struct {Local_dir stringServer_dir stringServer_host string}type jason struct {Period stringExec_period periodBackup backupTypeIncremental_save string}
虽然可以将其编组为map[string]interface{}，但如果数据具有固定的结构（如你的问题中的结构），你的解决方案可能更可取。使用interface{}将需要类型断言，可能会变得混乱。你的示例将如下所示：
parsedMap["exec_period"].(map[string]interface{})["end"].(map[string]interface{})["minute"].(float64)
英文:
Your code is fine except that the json package can only work with exported fields.
Everything will work if you capitalize the first letter for each field name:
type date struct {Month float64Week float64Day float64Hour float64Minute float64}type period struct {Start dateEnd date}type backupType []struct {Local_dir stringServer_dir stringServer_host string}type jason struct {Period stringExec_period periodBackup backupTypeIncremental_save string}
While it is possible to marshal into a map[string]interface{}, if the data has a set structure (such as the one in your question), your solution is most likely preferable. Using interface{} would require type assertions and might end up looking messy. Your example would look like this:
parsedMap["exec_period"].(map[string]interface{})["end"].(map[string]interface{})["minute"].(float64)
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