动态遍历结构中的每个字段并进行更改

Question

How to go through all fields in a struct and edit/validate them on the fly?

Example:

func UrlEncodeStruct(s interface{}) {
  r := reflect.ValueOf(obj)
  for i := 0; i < r.NumField(); i++ {
    value := r.Field(i).String()
    value = url.QueryEscape(value)
    r.Field(i).SetString(value)
  }
}

Answer 1

To modify the struct value in the caller, change the function to take a pointer to the struct value. Otherwise, the posted function is correct for a struct containing only exported string fields.

func UrlEncodeStruct(s interface{}) {
    r := reflect.ValueOf(s).Elem()  // <-- note call to Elem() here
    for i := 0; i < r.NumField(); i++ {
        value := r.Field(i).String()
        value = url.QueryEscape(value)
        r.Field(i).SetString(value)
    }
}

Call it like this:

var s someStructType
UrlEncodeStruct(&s)

playground example