Golang：类型[type]不是表达式;(Golang: Type [type] is not an expression; json config parsing)

 我试图找出一些代码来从JSON文件中提取配置。 当我尝试构建时，出现此错误 
 
 
 以下是我正在尝试使用的配置和程序代码。 我目前发现的每个例子都与下面的代码类似。 任何关于我做错了什么的建议？ 
 

I'm trying to work out a bit of code to pull in config from a JSON file. When I attempt to build, I get this error
 
 
Below is the config and program code I'm trying to work with. Every example I've found so far is similar to the below code. Any suggestion of what I'm doing incorrectly?
 

type ConfigVars is not an expression

-- Config File
{"beaconUrl":"http://test.com/?id=1"}

-- Program Code
package main

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


type ConfigVars struct {
    BeaconUrl   string
}


func main() {
    configFile, err := os.Open("config.json")
    defer configFile.Close()
    if err != nil {
        fmt.Println("Opening config file", err.Error())
    }

    jsonParser := json.NewDecoder(configFile)
    if err = jsonParser.Decode(&ConfigVars); err != nil {
        fmt.Println("Parsing config file", err.Error())
    }
}

type ConfigVars is not an expression

-- Config File
{"beaconUrl":"http://test.com/?id=1"}

-- Program Code
package main

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


type ConfigVars struct {
    BeaconUrl   string
}


func main() {
    configFile, err := os.Open("config.json")
    defer configFile.Close()
    if err != nil {
        fmt.Println("Opening config file", err.Error())
    }

    jsonParser := json.NewDecoder(configFile)
    if err = jsonParser.Decode(&ConfigVars); err != nil {
        fmt.Println("Parsing config file", err.Error())
    }
}

 你在那里做的是试图传递一个指向ConfigVars类型的指针（这显然并不意味着什么）。 你想要做的是制作一个类型为ConfigVars的变量，并传递一个指向它的指针： 
 

What you're doing there is trying to pass a pointer to the ConfigVars type (which obviously doesn't really mean anything). What you want to do is make a variable whose type is ConfigVars and pass a pointer to that instead:
 

var cfg ConfigVars
err = jsonParser.Decode(&cfg)
...

var cfg ConfigVars
err = jsonParser.Decode(&cfg)
...