Parse JSON from local url with JQuery

问题

I have a local url where i can retrieve a json file. I also have a simple website which is build using JQuery.

I've looked up many sites for tutorials and sample code on how to retrieve the json input and parse it so i can display it on my site. However non were helpful as i still can't make it work.

So as a last resort i'm going to ask stackoverflow for your help. I have a lot of java knowledge, but I'm relative new to 'web'-development and know some basics of javascript.

This is a sample output of my url:

[
    {
        "baken": "not implemented...",
        "deviceType": "Optimus 2X",
        "batteryLevel": "1.0",
        "gps": {
            "speed": 0,
            "Date": "TueNov0100: 34: 49CET2011",
            "Accuracy": 35,
            "longitude": {removed},
            "latitude": {removed},
            "Provider": "gps"
        },
        "deviceId": "4423"
    },
    {
        "baken": "notimplemented...",
        "deviceType": "iPhone",
        "batteryLevel": "30.0",
        "gps": {
            "speed": 0,
            "Date": "TueNov0116: 18: 51CET2011",
            "Accuracy": 65,
            "longitude": {removed},
            "latitude": {removed},
            "Provider": null
        },
        "deviceId": "4426"
    }
]

Hope you can help me..

回答1:

If you are running a local web-server and the website and the json file are served by it you can simply do:

$.getJSON('path/to/json/file.json', function(data) {
  document.write(data);
})

If you are just using files and no webserver you might get a problem with the origin-policy of the browser since AJAX request cannot be send via cross-domain and the origin domain is 'null' per default for request from local files.

If you are using Chrome you can try the --allow-file-access-from-files parameter for developing purposes.

回答2:

Your URL returns invalid json. Try pasting it in jsonlint.com and validating it there and you'll see what I mean. Even the code highlighting here on stackoverflow is showing you what's wrong. :)

Edit: To parse it you can use jQuery.parseJSON

 jQuery.parseJSON('{"foo": "goo"}');

回答3:

$.get('/some.json', function(data) {
  // data[0]["baken"] == "not implemented..."
});

See http://api.jquery.com/jQuery.get/

回答4:

You don't need to parse the json -- that is why people like it. It becomes a native JavaScript object.

For your example if you put the results in a variable called data then you could do things like this:

 data[0].deviceType // would be "Optimus 2x"
 data[0].gps.speed  // would be numeric 0

etc.

回答5:

The most natural way is to allow jQuery to make an AJAX call for you once you've already entered the page. Here's an example:

    $.ready(function() {

         // put your other code for page initialization here

         // set up a global object, for namespacing issues, to hold your JSON.
         // this allows your to be a good "web" citizen, because you will create
         // one object in the global space that will house your objects without
         // clobbering other global objects from other scripts, e.g., jQuery
         // makes the global objects '$' and 'jQuery' 
         myObjects = {};

         // start JSON retrieval here
         $.getJSON('/path/to/json/file.json', function(data) {
             // 'data' contains your JSON.
             // do things with it here in the context of this function.
             // then add it to your global object for later use.
             myObjects.myJson = data; 
         });

    });

The API documentation is here

来源：https://stackoverflow.com/questions/8021022/parse-json-from-local-url-with-jquery

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javascript

json

jquery

getjson