从文件读取json数据

Question

I am running a server with Go programming language, and when I load the server in the browser, the temp handler function is called and the getjson.html file is served by this temp Handler function. Now the screen shows a "Get Json Data" button. On clicking this button, I am not getting any results (as something should be displayed on the screen).

I checked the javascript console and there are no errors as such. I am not able to figure out what the problem is, why isn't there any output on the screen.

Contents of servejson.go :

package main

import (
    "http"
    "flag"
)

var path = flag.String("root", "/home/chinmay/work/json/getjson.html", "Set root directory, use absolute path")

func temp(w http.ResponseWriter, r *http.Request){
    w.Header().Set("Content-Type", "text/html")
    http.ServeFile(w,r,*path)
}

func main(){
    http.HandleFunc("/",temp)
    http.ListenAndServe(":8080", nil)
}

Contents of getjson.html :

package main

import (
    "http"
    "flag"
)

var path = flag.String("root", "/home/chinmay/work/json/getjson.html", "Set root directory, use absolute path")

func temp(w http.ResponseWriter, r *http.Request){
    w.Header().Set("Content-Type", "text/html")
    http.ServeFile(w,r,*path)
}

func main(){
    http.HandleFunc("/",temp)
    http.ListenAndServe(":8080", nil)
}

Contents of json_data.js:

{ 
  "firstName": "John",
  "lastName": "Doe",
  "age": 25
}

Answer 1

Yes, you can. Live example. Provided that json.txt is a resource next to the document in which this code is running, and (on some browsers) provided this is not running from a local file (e.g., a file:// URL rather than an http:// one; some browsers are okay with local files accessing other local files via ajax, others are not).

A couple of notes:

• In the

  $("div").append(field + " ");
  

  line, field will be the value of each property (e.g., "John").

• The order in which the properties are listed is completely undefined.

So for this specific example, you'd probably be better off with

<script type="text/javascript">
$(document).ready(function(){
  $("button").click(function(){
    $.getJSON("json.txt",function(result){
      $("div").append(result.firstName + " " + result.lastName + " " + result.age);
    });
  });
});
</script>

Live example

---

Update: From your comments on another answer, it seems like you might be unclear on where and how the script code is running. The JavaScript script runs on the client's browser. The path to use to reference json.txt is exactly like (say) the path to an image you want to show on a page. json.txt must be accessible via the web server, just like an image would need to be accessible via the web server. Think of json.txt as just another resource used by your web page, like any other. In terms of the path, and how you have to make json.txt available, the same rules apply. To be clear: Script running client-side in a web page cannot access a server-side file that can't be retrieved by the browser.

---

Update 2: You've posted more code, and it looks like you've made your server only serve the getjson.html file. Your server also has to serve the json.txt file, or the browser can't access it.