可以在Go中获取JSON的值

Question

I'm new in Go. I'm trying to read a JSON file and get a part of it for then operate with the values obtained. My JSON is in the file example.json:

{"results":[{"statement_id":0,"series":[{"name":"cpu/node_utilization","columns":["time","distinct"],"values":[[10,1],[11,3],[13,5]]}]}]}

So what I would like to get is the "values" for get the sum of all the elements. In this case: 1+3+5

Here is the code that I have. I'm available to get the results, but then I don't manage to get series.

Here is the code that I have:

package main

import (
    "encoding/json"
    "fmt"
    "io/ioutil"
    "os"
)

func main() {
    // Open our jsonFile
    jsonFile, err := os.Open("example.json")
    // if we os.Open returns an error then handle it
    if err != nil {
        fmt.Println(err)
    }
    fmt.Println("Successfully Opened example.json")
    // defer the closing of our jsonFile so that we can parse it later on
    defer jsonFile.Close()

    byteValue, _ := ioutil.ReadAll(jsonFile)
    var all_data map[string]interface{}
    json.Unmarshal([]byte(byteValue), &all_data)
    fmt.Println(all_data["results"])
}

I've tried diferent solutions like all_data["results"].(map[string]interface{})["series"]) But the problem is that the map is in an array, and I don't know how to solve it.

Answer 1

I have solved defining an Struct.

package main

import (
"encoding/json"
"fmt"
"io/ioutil"
"os"
)


type AutoGenerated struct {
    Results []struct {
        StatementID int `json:"statement_id"`
        Series      []struct {
            Name    string   `json:"name"`
            Columns []string `json:"columns"`
            Values  [][]int  `json:"values"`
        } `json:"series"`
    } `json:"results"`
}

func main() {
    // Open our jsonFile
jsonFile, err := os.Open("example.json")
// if we os.Open returns an error then handle it
if err != nil {
    fmt.Println(err)
}
fmt.Println("Successfully Opened example.json")
// defer the closing of our jsonFile so that we can parse it later on
defer jsonFile.Close()


byteValue, _ := ioutil.ReadAll(jsonFile)
all_data := AutoGenerated{}
json.Unmarshal([]byte(byteValue), &all_data)
fmt.Println(all_data.Results[0].Series[0].Values)
}

I have used this web to generate automatically the Struct providing the JSON structure