Go - JSON

• ex. var p = Person{}; json.Marshal(p)
• json.marshal return byte slice contains long string wuthout extraneous
  
• Ex.data, err = json.MarshalIndent to format jaon. Use fmt.Printf(”%s”,data) to print to string
  
• Only exported fields are marshalled
  
• Field tags is a string of meta data associated at compile time with a field of a struct.
• Ex. type S struct {num int `json:“release”`, real bool `json:“ok,omitempty”`}
• omitempty indicate no output value if variable is zero value
  
• Unmarshal object. json.Unmarshal
• Ex. Unmarshal json to slice. (How the type is decided? Always slice?)
• • Ex. type Person struct {Name string}; ps := json.Unmarshal(json)
  • var titles []struct{ Title string }; if err := json.Unmarshal(data, &titles);
    
• Field of Struct used to unmarshal json must be capitalized. But map from json to struct is case insensitive