go: json marshal and unmarshal
引用：
https://bluehive.medium.com/golang-json-marshal-a-struct-with-pointers-2a362d0543f5
1. Golang JSON Marshal a Struct With Pointers：
a. Always name member names in upper case: the lower case name is never marshalled
b.golang marshaller can process nested struct with pointer fields
package main import ( "encoding/json" "fmt" ) type Num struct { N int } type Packed struct { PNum *Num Name string } func main() { num := &Num{N: 100} packed := Packed{PNum: num, Name: "xx-packed-xy"} dataInBytes, err := json.Marshal(packed) fmt.Printf("%+v data=%s\n", err, string(dataInBytes)) unpacked := &Packed{} err = json.Unmarshal(dataInBytes, unpacked) fmt.Printf("%v %+v\n", err, unpacked.PNum) } //Output <nil> data={"PNum":{"N":100},"Name":"xx-packed-xy"} <nil> &{N:100}