使用UnmarshalJSON()覆盖控制解组过程。
https://play.golang.org/p/pCSgymQYC3
package main
import (
"log"
"encoding/json"
"bytes"
)
const(
s1=`{"query":{"count":1,"created":"2016-05-11T02:12:33Z","lang":"en-US","results":{"quote":{"Change":"+0.21","DaysLow":"9.32","DaysHigh":"9.68","Name":"Alcoa Inc. Common Stock","Open":"9.56","PreviousClose":"9.46","Symbol":"aa","Volume":"22266533","PercentChange":"+2.22%"}}}}`
s2=`{"query":{"count":2,"created":"2016-05-11T02:17:48Z","lang":"en-us","results":{"quote":[{"Change":"+0.21","DaysLow":"9.32","DaysHigh":"9.68","Name":"Alcoa Inc. Common Stock","Open":"9.56","PreviousClose":"9.46","Symbol":"aa","Volume":"22266533","PercentChange":"+2.22%"},{"Change":"+0.63","DaysLow":"92.11","DaysHigh":"93.57","Name":"Apple Inc.","Open":"93.35","PreviousClose":"92.79","Symbol":"aapl","Volume":"33686836","PercentChange":"+0.68%"}]}}}`
)
type QueryResult struct {
//Id bson.ObjectId `bson:"_id,omitempty"`
Query Query `json:"query"`
}
type Query struct {
Count int `json:"count"`
Created string `json:"created"`
Lang string `json:"lang"`
Results Quote `json:"results"`
}
type structOrArray struct{
parent *Quote
s StockQuote
a []StockQuote
}
func (this *structOrArray)UnmarshalJSON(data []byte) error{
d := json.NewDecoder(bytes.NewBuffer(data))
t, err := d.Token();
if err != nil{
return err
}
if t==json.Delim('['){
if err := json.Unmarshal(data, &this.a);err != nil {
return err
}
return nil
}
if err := json.Unmarshal(data, &this.s);err != nil {
return err
}
return nil
}
type fakeQuote struct{
Load structOrArray `json:"quote"` //Here is the difference. Do I need to re-write the whole struct in order to handle []
}
type Quote struct {
Quote *StockQuote
Quotes []StockQuote
}
func (this *Quote)UnmarshalJSON(data []byte) error{
fq := fakeQuote{}
if err := json.Unmarshal(data, &fq);err != nil{
return err
}
this.Quote = &fq.Load.s
this.Quotes = fq.Load.a
return nil
}
type StockQuote struct {
Change string `json:"change"`
PercentChange string `json:"percentChange"`
DaysLow string `json:"daysLow"`
DaysHigh string `json:"daysHigh"`
Open string `json:"open"`
PreviousClose string `json:"previousClose"`
Symbol string `json:"symbol"`
Name string `json:"name"`
Volume string `json:"volume"`
}
func main() {
r := QueryResult{}
err := json.Unmarshal([]byte(s1), &r)
if err != nil {
log.Fatalln(err)
}
log.Println(r.Query.Results.Quote)
log.Println(r.Query.Results.Quotes)
err = json.Unmarshal([]byte(s2), &r)
if err != nil {
log.Fatalln(err)
}
log.Println(r.Query.Results.Quote)
log.Println(r.Query.Results.Quotes)
}