Go 使用Unmarshal将json赋给struct出错的原因及解决

例如：

{
 "name": "Laura"
 "age": "18"
}

type PersonalInfo struct {
 Name string `json:"name"`
 Age string `json:"age"`
}

person := PersonalInfo{}
err := json.Unmarshal(json, &persona)//json为上面的[]byte

1、struct中变量名是不可导出的（首写字母是小写的），需要把首写字母改成大写

2、需要传输person的指针

3、struct中json的名字与json中的名字需要一模一样

补充：Go语言处理JSON之——利用Unmarshal解析json字符串

首先还是从官方文档中的例子：

package main
import (
 "fmt"
 "encoding/json"
)
type Animal struct {
 Name string
 Order string
}
func main() {
 var jsonBlob = []byte(`[
 {"Name": "Platypus", "Order": "Monotremata"},
 {"Name": "Quoll", "Order": "Dasyuromorphia"}
 ]`)
 var animals []Animal
 err := json.Unmarshal(jsonBlob, &animals)
 if err != nil {
  fmt.Println("error:", err)
 }
 fmt.Printf("%+v", animals)
}

输出：

[{Name:Platypus Order:Monotremata} {Name:Quoll Order:Dasyuromorphia}]

简单进行修改，修改为：

package main
import (
 "fmt"
 "encoding/json"
)
type Animal struct {
 Name string
 Order string
}
func main() {
 var jsonBlob = []byte(`{"Name": "Platypus", "Order": "Monotremata"}`)
 var animals Animal
 err := json.Unmarshal(jsonBlob, &animals)
 if err != nil {
  fmt.Println("error:", err)
 }
 fmt.Printf("%+v", animals)
}

输出：

{Name:Platypus Order:Monotremata}

解析这样的一个json字符串：

{
 "first fruit":
 {
  "describe":"an apple",
  "icon":"appleIcon",
  "name":"apple"
 },
 "second fruit":
 {
  "describe":"an orange",
  "icon":"orangeIcon",
  "name":"orange"
 },
 "three fruit array":
 [
  "eat 0",
  "eat 1",
  "eat 2",
  "eat 3",
  "eat 4"
 ]
}

package main
import (
 "fmt"
 "encoding/json"
)
type Fruit struct {
 Describe string `json:"describe"`
 Icon  string `json:"icon"`
 Name  string `json:"name"`
}
type FruitGroup struct {
 FirstFruit *Fruit `json:"first fruit"` //指针，指向引用对象；如果不用指针，只是值复制
 SecondFruit *Fruit `json:"second fruit"` //指针，指向引用对象；如果不用指针，只是值复制
 THreeFruitArray []string `json:"three fruit array"`
}
func main() {
 var jsonBlob = []byte(`{
 "first fruit": {
  "describe": "an apple",
  "icon": "appleIcon",
  "name": "apple"
 },
 "second fruit": {
  "describe": "an orange",
  "icon": "appleIcon",
  "name": "orange"
 },
 "three fruit array": [
  "eat 0",
  "eat 1",
  "eat 2",
  "eat 3"
 ]}`)
 var fruitGroup FruitGroup
 err := json.Unmarshal(jsonBlob, &fruitGroup)
 if err != nil {
  fmt.Println("error:", err)
 }
 fmt.Printf("%+v\n", fruitGroup)
 fmt.Printf("%+v\n", fruitGroup.FirstFruit)
 fmt.Printf("%+v\n", fruitGroup.SecondFruit)
}

运行结果：

{FirstFruit:0xc00006c5a0 SecondFruit:0xc00006c5d0 THreeFruitArray:[eat 0 eat 1 eat 2 eat 3]}
&{Describe:an apple Icon:appleIcon Name:apple}
&{Describe:an orange Icon:appleIcon Name:orange}

以上为个人经验，希望能给大家一个参考，也希望大家多多支持编程网。如有错误或未考虑完全的地方，望不吝赐教。