javascript - 将整个 json 文件作为数组加载到变量中

Question

我想获取外部 json 文件 (locations.json) 并将内容加载到变量中。然后，我想使用此处提供的信息来使用此变量:http://www.json.org/js.html

我在尝试将外部 json 加载到变量时遇到了很多麻烦。我已经仔细查看了这个( load json into variable )页面，但没有一个页面真正填充了该变量。当稍后显示变量的内容时，它看起来是空的。

$("#testContain").html("<p>" + json + "</p>");

使用最后一个链接中列出的方法，这会显示“未定义”。

我使用的 json 文件如下所示:

[{"id":"1","locname":"Dunstable Downs","lat":"51.8646","lng":"-0.536957","address":"Chiltern Gateway Centre","address2":"","city":"","state":"England","postal":"","phone":"","web":"http:\/\/www.nationaltrust.org.uk\/main\/w-dunstabledownscountrysidecentrewhipsnadeestate","hours1":"","hours2":"","hours3":""},
{"id":"2","locname":"West Delta Park","lat":"45.5974","lng":"-122.688","address":"N Broadacre St and N Expo Rd, Portland","address2":"","city":"","state":"OR","postal":"","phone":"","web":"http:\/\/en.wikipedia.org\/wiki\/Delta_Park","hours1":"","hours2":"","hours3":""}]

大家有什么建议吗？

Answer 1

问题是请求是异步的。您可以按照您链接到的问题的已接受答案的建议进行同步调用，但这通常不是一个好主意，因为它会在等待响应时完全卡住浏览器。

变量分配得很好，但是当你在请求之后使用它时，你必须确保它是在得到响应之后，而不是在发送请求之后。在 getJSON 方法的回调中使用值是确保您拥有该值的最简单方法:

var my_json;
$.getJSON(my_url, function(json) {
  my_json = json;
  // here you have the value
});
// here you don't have the value, as this happens before the response arrives