Go语言JSON序列化：揭秘结构体字段导出规则与常见陷阱

package main

import (
  "encoding/json"
  "fmt"
)

type Address struct {
  street string // 小写字母开头，字段不可导出
  extended string
  city string
  state string
  zip string
}

type Name struct {
  first string // 小写字母开头，字段不可导出
  middle string
  last string
}

type Person struct {
  name Name      // 嵌套结构体字段，小写字母开头，不可导出
  age int        // 小写字母开头，字段不可导出
  address Address
  phone string
}

func main() {
  myname := Name{"Alfred", "H", "Eigenface"}
  myaddr := Address{"42 Place Rd", "Unit 2i", "Placeton", "ST", "00921"}
  me := Person{myname, 24, myaddr, "000 555-0001"}

  b, err := json.Marshal(me)

  if err != nil {
    fmt.Println("序列化错误:", err)
  }

  fmt.Println("序列化结果:", string(b)) // 输出: 序列化结果: {}
  fmt.Println("原始结构体:", me)       // 输出: 原始结构体: { {Alfred H Eigenface} 24 {42 Place Rd Unit 2i Placeton ST 00921} 000 555-0001}
}

package main

import (
  "encoding/json"
  "fmt"
)

type Address struct {
  Street   string `json:"street"`    // 首字母大写，可导出
  Extended string `json:"extended"`
  City     string `json:"json_city"` // 示例：自定义JSON字段名
  State    string `json:"state"`
  Zip      string `json:"zip"`
}

type Name struct {
  First  string `json:"first"`
  Middle string `json:"middle,omitempty"` // 示例：使用omitempty标签
  Last   string `json:"last"`
}

type Person struct {
  Name    Name    `json:"name"`
  Age     int     `json:"age"`
  Address Address `json:"address"`
  Phone   string  `json:"phone"`
}

func main() {
  myname := Name{First: "Alfred", Middle: "H", Last: "Eigenface"}
  myaddr := Address{Street: "42 Place Rd", Extended: "Unit 2i", City: "Placeton", State: "ST", Zip: "00921"}
  me := Person{Name: myname, Age: 24, Address: myaddr, Phone: "000 555-0001"}

  b, err := json.Marshal(me)

  if err != nil {
    fmt.Println("序列化错误:", err)
    return
  }

  fmt.Println("序列化结果:", string(b))
  // 预期输出示例:
  // {"name":{"first":"Alfred","middle":"H","last":"Eigenface"},"age":24,"address":{"street":"42 Place Rd","extended":"Unit 2i","json_city":"Placeton","state":"ST","zip":"00921"},"phone":"000 555-0001"}
}