How to parse JSON data in Golang?

Parsing JSON data in Golang involves four main steps: Import the आवश्यक package, which includes json, fmt and ioutil. Read JSON data from a file. Decode JSON data into a structure or map. Access key-value pairs in a map or use a decoded struct.

How to parse JSON data in Golang

Golang provides powerful tools to process JSON data, which can be achieved through the following steps:

1. Import necessary packages

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

2. Read JSON data from file

jsonFile, err := ioutil.ReadFile("data.json")
if err != nil {
    fmt.Println("Error reading JSON file:", err)
    return
}

3. Decode JSON data into structure or map

Decoding To the structure:

type Person struct {
    Name string
    Age  int
}

var person Person
err = json.Unmarshal(jsonFile, &person)
if err != nil {
    fmt.Println("Error decoding JSON data:", err)
    return
}

Decode into the map:

var data map[string]interface{}
err = json.Unmarshal(jsonFile, &data)
if err != nil {
    fmt.Println("Error decoding JSON data:", err)
    return
}

// 访问 map中的键值对
fmt.Println("Name:", data["Name"])

Practical case

Read the JSON file and print the name and age:

package main

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

type Person struct {
    Name string
    Age  int
}

func main() {
    jsonFile, err := ioutil.ReadFile("data.json")
    if err != nil {
        fmt.Println("Error reading JSON file:", err)
        return
    }

    var person Person
    err = json.Unmarshal(jsonFile, &person)
    if err != nil {
        fmt.Println("Error decoding JSON data:", err)
        return
    }

    fmt.Printf("Name: %s, Age: %d\n", person.Name, person.Age)
}

Save the following JSON data to the file:

{
  "Name": "John Doe",
  "Age": 30
}

Then run the program, the output is as follows:

Name: John Doe, Age: 30

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