Golang omitempty的用法

omitempty作用是在json数据结构转换时，当该字段的值为该字段类型的零值时，忽略该字段。

package main

import (
	"fmt"
	"encoding/json"
)


type Student struct {
	Name string `json:"name"`
	Age int  `json:"age"`
	Grade  string `json:"grade,omitempty"`
}

func main() {
	stu1 := Student{
		Name:"Tom",
		Age:18,
		Grade:"middle school",
	}

	stu2  := Student{
		Name:"LiLy",
		Age:19,
	}

	stuByts1,_ := json.Marshal(&stu1)

	stuByts2 ,_ := json.Marshal(&stu2)

	fmt.Println("stu1:",string(stuByts1))
	fmt.Println("stu2:",string(stuByts2))
}

打印结果如下：
stu1: {"name":"Tom","age":18,"grade":"middle school"}
stu2: {"name":"LiLy","age":19}