javascript - 如何直接从 url 访问 JSON 数组

Question

我是 javascript 的新手，我在 url 中有一个 Json 数组，如下所示；

[{"year":2015,"month":4,"day":1,"num":0,"time":"2015-04-01","hour":0,"zone":3,"state1":2137,"state2":249,"state3":1810,"state4":30,"state5":0},....]

我想访问 state1 值并将该值分配给我拥有的变量。我该怎么做？(是否需要解析或是否有任何方法可以直接访问 URL 中的 JSON 对象)。如果我问错了，我很抱歉。

Answer 1

您可以使用 jQuery getJSON()功能:

$.getJSON(' localhost:8080/dataurl', function(data) {
  //data is the JSON string
  var jsonObj = JSON.parse(data);    
});

现在，下面是解析 jsonObj 以获取 state1 的方法。

使用数组 map()方法:

var jsonObj = [
                {
                  "year":2015,
                  "month":4,
                  "day":1,
                  "num":0,
                  "time":"2015-04-01",
                  "hour":0,
                  "zone":3,
                  "state1":2137,
                  "state2":249,
                  "state3":1810,
                  "state4":30,
                  "state5":0
                },
                {
                  "year":2016,
                  "month":12,
                  "day":1,
                  "num":0,
                  "time":"2015-04-01",
                  "hour":0,
                  "zone":3,
                  "state1":2474,
                  "state2":250,
                  "state3":1811,
                  "state4":31,
                  "state5":0
                }
              ];

var state1arr = jsonObj.map(function(item) {
  return item.state1;
});

console.log(state1arr);

使用 for...in循环:

var jsonObj = [
                {
                  "year":2015,
                  "month":4,
                  "day":1,
                  "num":0,
                  "time":"2015-04-01",
                  "hour":0,
                  "zone":3,
                  "state1":2137,
                  "state2":249,
                  "state3":1810,
                  "state4":30,
                  "state5":0
                },
                {
                  "year":2016,
                  "month":12,
                  "day":1,
                  "num":0,
                  "time":"2015-04-01",
                  "hour":0,
                  "zone":3,
                  "state1":2474,
                  "state2":250,
                  "state3":1811,
                  "state4":31,
                  "state5":0
                }
              ];

var state1arr = [];
for (var i in jsonObj) {
  state1arr.push(jsonObj[i].state1);
}

console.log(state1arr);