How to Unmarshal the json array?

Question

There is something wrong when I unmarshal the json array.
How do I correct it ? the code is:http://play.golang.org/p/AtU9q8Hlye

package main

import (
    "encoding/json"
    "fmt"
)

type Server struct {
    ServerName string
    ServerIP   string
}

type Serverslice struct {
    Name    string
    Servers []Server
}

func main() {
    var s []Serverslice
    str := `{"name":"dxh","servers":[{"serverName":"VPN0","serverIP":"127.0.0.1"},{"serverName":"Beijing_VPN","serverIP":"127.0.0.2"}],
        "name":"dxh1,"servers":[{"serverName":"VPN1","serverIP":"127.0.0.1"},{"serverName":"Beijing_VPN","serverIP":"127.0.0.2"}]}`

    json.Unmarshal([]byte(str), &s) //the wrong line.....................
    fmt.Println(len(s))
}

Answer 1

First of all, you're ignoring the error return value from json.Unmarshal. You probably want something like:

if err := json.Unmarshal([]byte(str), &s); err != nil {
    log.Fatalln(err)
}

With that change, we can see that your JSON data isn't valid: invalid character 's' after object key:value pair. There is a missing quote at the end of "dxh1 on the second line.

Fixing that error and rerunning the program you'll get a different error: json: cannot unmarshal object into Go value of type []main.Serverslice. There are two possible problems here:

1. You meant to decode into an object. In this case, just declare s as a Serverslice. Here is a version of your program that makes that change: http://play.golang.org/p/zgyr_vnn-_

2. Your JSON is supposed to be an array (possible, since it seems to have duplicate keys). Here's an updated version with the JSON changed to provide an array: http://play.golang.org/p/Wl6kUaivEm