package main

import (
    "encoding/json"
    "fmt"
    "strings"
)

type Item struct {
    Value  *int
}


func main() {
    var jsonBlob = `[
        {},
        {"Value": null},
        {"Value": 0},
        {"Value": 1}
    ]`
    var items []Item

    err := json.NewDecoder(strings.NewReader(jsonBlob)).Decode(&items)
    if err != nil {
        fmt.Println("error:", err)
    }
    for _, a := range items {
        if a.Value != nil {
            fmt.Println(*a.Value)
        } else {
            fmt.Println(a.Value)
        }
    }
}

<nil>
<nil>
0
1

<nil>
<error>
0
1