how to Unmarshal json in golang

huangapple
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英文:

how to Unmarshal json in golang

问题

我有一个 JSON 数据：

  1. {"code":200,
  2.  "msg":"success",
  3.  "data":{"url":"https:\/\/mp.weixin.qq.com\/cgi-bin\/showqrcode?ticket=gQHQ7jwAAAAAAAAAAS5odHRwOi8vd2VpeGluLnFxLmNvbS9xLzAyX3pqS0pMZlA4a1AxbEJkemhvMVoAAgQ5TGNYAwQsAQAA"}}

我定义了一个结构体：

  1. type Result struct {
  2. 	code int
  3. 	msg  string                 `json:"msg"`
  4. 	data map[string]interface{} `json:"data"`
  5. }

对于这段代码：

  1. var res Result
  2. json.Unmarshal(body, &res)
  3. fmt.Println(res)

输出结果是：{0 map[]}

我想要获取 data 中的 url，该如何获取呢？

英文:

I have a json:

  1. {"code":200,
  2.  "msg":"success",
  3.  "data":{"url":"https:\/\/mp.weixin.qq.com\/cgi-bin\/showqrcode?ticket=gQHQ7jwAAAAAAAAAAS5odHRwOi8vd2VpeGluLnFxLmNvbS9xLzAyX3pqS0pMZlA4a1AxbEJkemhvMVoAAgQ5TGNYAwQsAQAA"}}

and i define a struct :

  1. type Result struct {
  2. 	code int
  3. 	msg  string                 `json:"msg"`
  4. 	data map[string]interface{} `json:"data"`
  5. }

for this code:

  1. var res Result
  2. json.Unmarshal(body, &res)
  3. fmt.Println(res)

the output is: {0 map[]}

i want to get url in data, how to get it?

答案1

得分: 4

你应该通过将字段（Code、Msg、Data）的首字母大写来导出Result的字段（code、msg、data），以便访问（设置/获取）它们：

  1. package main
  3. import (
  4. 	"encoding/json"
  5. 	"fmt"
  6. )
  8. type Result struct {
  9. 	Code int                    `json:"code"`
  10. 	Msg  string                 `json:"msg"`
  11. 	Data map[string]interface{} `json:"data"`
  12. }
  14. func main() {
  15. 	str := `{"code":200,"msg":"success","data":{"url":"https://mp.weixin.qq.com/cgi-bin/showqrcode?ticket=gQHQ7jwAAAAAAAAAAS5odHRwOi8vd2VpeGluLnFxLmNvbS9xLzAyX3pqS0pMZlA4a1AxbEJkemhvMVoAAgQ5TGNYAwQsAQAA"}}`
  16. 	var res Result
  17. 	err := json.Unmarshal([]byte(str), &res)
  18. 	fmt.Println(err)
  19. 	fmt.Println(res)
  20. }

在https://play.golang.org/p/23ah8e_hCa上运行代码。

相关问题：https://stackoverflow.com/questions/24837432/golang-capitals-in-struct-fields

英文:

You should export fields (code, msg, data) for Result by capitalizing the first letter of fields (Code, Msg, Data) to access (set/get) them:

  1. package main
  3. import (
  4. 	"encoding/json"
  5. 	"fmt"
  6. )
  8. type Result struct {
  9. 	Code int                    `json:"code"`
  10. 	Msg  string                 `json:"msg"`
  11. 	Data map[string]interface{} `json:"data"`
  12. }
  14. func main() {
  15. 	str := `{"code":200,"msg":"success","data":{"url":"https:\/\/mp.weixin.qq.com\/cgi-bin\/showqrcode?ticket=gQHQ7jwAAAAAAAAAAS5odHRwOi8vd2VpeGluLnFxLmNvbS9xLzAyX3pqS0pMZlA4a1AxbEJkemhvMVoAAgQ5TGNYAwQsAQAA"}}`
  16. 	var res Result
  17. 	err := json.Unmarshal([]byte(str), &res)
  18. 	fmt.Println(err)
  19. 	fmt.Println(res)
  20. }

Play the code on https://play.golang.org/p/23ah8e_hCa

Related question: https://stackoverflow.com/questions/24837432/golang-capitals-in-struct-fields

huangapple
  • 本文由 发表于 2016年12月28日 13:25:32
  • 转载请务必保留本文链接：https://go.coder-hub.com/41355847.html
  • go
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