2019-08-30 21:29
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I have a JSON file like this:


    "namespace": "pulsarNamespace1",
    "name": "pulsarFunction1",
    "tenant": "pulsarTenant1"


    "namespace": "pulsarNamespace2",
    "name": "pulsarFunction2",
    "tenant": "pulsarTenant1"

I am attempting to deserialize/unmarshal this JSON array into a slice of structs, but I'm getting structs with empty (default) values.

When I run my code, it correctly reads my file into a string, but it's not deserializing the data correctly and just writes empty structs to the console, like this:

[]main.Config{main.Config{namespace:"", tenant:"", name:""}, main.Config{namespace:"", tenant:"", name:""}}

Namespace: Name: %!d(string=)

Namespace: Name: %!d(string=)

Here's my code in Go:

package main

import (
// Ignore the unused imports.

type Config struct {
    namespace string `json:"namespace,omitempty"`
    tenant    string `json:"tenant,omitempty"`
    name      string `json:"name,omitempty"`

func getConfigs() string {
    b, err := ioutil.ReadFile("fastDeploy_example.json") // just pass the file name
    if err != nil {
    str := string(b) // convert content to a 'string'
    fmt.Println(str) // print the content as a 'string'
    return str

func deserializeJson(configJson string) []Config {
    jsonAsBytes := []byte(configJson)
    configs := make([]Config, 0)
    err := json.Unmarshal(jsonAsBytes, &configs)
", configs)
    if err != nil {
    return configs

func main() {
    // Unmarshal each fastDeploy config component into a slice of structs.
    jsonConfigList := getConfigs()
    unmarshelledConfigs := deserializeJson(jsonConfigList)

    for _, configObj := range unmarshelledConfigs {
        fmt.Printf("Namespace: %s Name: %d
", configObj.namespace,

Moreover, if I understand the purpose of using omitempty, then it shouldn't even be writing the empty fields. However, it appears that it's writing them anyway.

How do I correctly deserialize/unmarshal my JSON array into my slice of structs in Golang?

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1条回答 默认 最新

  • dpk20361 2019-08-30 21:58

    Export the field names of your struct: Namespace, Tenant, Name, etc., so the unmarshaler can set them via reflection.

    Re: omitempty, that's a tag for the json marshaler. If you marshal your struct to json with empty strings, then those fields will be omitted. If you printf the struct, they will be printed.

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