go语言之进阶篇通过结构体生成json

1、通过结构体生成json

示例：

package main

import (
	"encoding/json"
	"fmt"
)

//成员变量名首字母必须大写
type IT struct {
	Company  string
	Subjects []string
	IsOk     bool
	Price    float64
}

func main() {
	//定义一个结构体变量，同时初始化
	s := IT{"itcast", []string{"Go", "C++", "Python", "Test"}, true, 666.666}

	//编码，根据内容生成json文本
	buf, err := json.Marshal(s)
	if err != nil {
		fmt.Println("err = ", err)
		return
	}
	fmt.Println("buf = ", string(buf))
}

执行结果：

buf =  {"Company":"itcast","Subjects":["Go","C++","Python","Test"],"IsOk":true,"Price":666.666}

2、根据结构体生成json

package main

import (
	"encoding/json"
	"fmt"
)

//成员变量名首字母必须大写
type IT struct {
	Company  string
	Subjects []string
	IsOk     bool
	Price    float64
}

func main() {
	//定义一个结构体变量，同时初始化
	s := IT{"itcast", []string{"Go", "C++", "Python", "Test"}, true, 666.666}

	//编码，根据内容生成json文本
	buf, err := json.MarshalIndent(s, "", "	") //格式化编码
	if err != nil {
		fmt.Println("err = ", err)
		return
	}

	fmt.Println("buf = ", string(buf))
}

执行结果：

buf =  {
	"Company": "itcast",
	"Subjects": [
		"Go",
		"C++",
		"Python",
		"Test"
	],
	"IsOk": true,
	"Price": 666.666
}

 3、struct_tag的使用 （通过二次编码,可以把大写变成小写，还可以以字符串方式输出）

示例： 

package main

import (
	"encoding/json"
	"fmt"
)

//成员变量名首字母必须大写
type IT struct {
	//Company  string   `json:"-"` //此字段不会输出到屏幕

	//下面的写法都是二次编码,可以把大写变成小写
	Company  string   `json:"company"`
	Subjects []string `json:"subjects"`
	IsOk     bool     `json:"isok"`
	//转成字符串再输出编码
	//IsOk  bool    `json:"string"`
	Price float64 `json:"price"`
}

func main() {
	//定义一个结构体变量，同时初始化
	s := IT{"itcast", []string{"Go", "C++", "Python", "Test"}, true, 666.666}

	//编码，根据内容生成json文本
	buf, err := json.MarshalIndent(s, "", " ") //格式化编码
	if err != nil {
		fmt.Println("err = ", err)
		return
	}

	fmt.Println("buf = ", string(buf))
}

执行结果：

buf =  {
 "company": "itcast",
 "subjects": [
  "Go",
  "C++",
  "Python",
  "Test"
 ],
 "isok": true,
 "price": 666.666
}