我想通过将文件名作为GoLang中的用户输入来读取文件

Question

I have a JSON file called example.json. I need to read this file by taking its name as user input. I have tried with the below code.

func main() {
    reader := bufio.NewReader(os.Stdin)
    fmt.Print("Enter text: ")
    text,_ := reader.ReadString('
')


    fmt.Println(text)

    file,_ := ioutil.ReadFile(text)
    // os.Exit()
    fmt.Print(file)
}

But It's not working properly. I want to take the JSON file name as a command line input and read the JSON file.

I checked with the below method. But it's not matched with my case.

reader.ReadString does not strip out the first occurrence of delim

Answer 1

First things first. You can figure out why your code doesn't work if you simply deal with the errors properly. You're ignoring the error thrown when you call iotuil.ReadFile(text). Just add the proper treatment and you will have a good clue why it isn't working

file, err := ioutil.ReadFile(text)
if err != nil {
    log.Fatal(err)
}

: no such file or directory

The reason why your program does not work is likely because there's a break line character in your text variable.

From Go Documentation

"ReadString reads until the first occurrence of delim in the input, returning a string containing the data up to and including the delimiter."

Remove the break like character from the variable that holds your user's input and it should work, assuming the input actually matches to a existing file including its correct path.

func main() {
    reader := bufio.NewReader(os.Stdin)
    fmt.Print("Enter text: ")
    text, _ := reader.ReadString('
')

    text = strings.TrimSuffix(text, "
")

    //Add the file path
    //or else the user will be required to enter the entire file location
    f := "path_to_the_file" + text 

    file, err := ioutil.ReadFile(f)

    if err != nil {
        log.Fatal(err)
    }

    fmt.Println(string(file))
}