java - JsonPath : filter by value in array

Question

我正在尝试使用 Jsonpath 按值过滤我的 Json 中的数组。我想在下面的 JSON 中获取国家/地区的 long_name。为此，我按 types[0] == "country"过滤了 adress_components，但它似乎不起作用。

我试过的 JsonPath :

$.results[0].address_components[?(@['types'][0]=="country")].long_name

我想要的结果是:“加拿大”。

JSON:

{
       "results" : [
          {
             "address_components" : [
                {
                   "long_name" : "5510-5520",
                   "short_name" : "5510-5520",
                   "types" : [ "street_number" ]
                },
                {
                   "long_name" : "Yonge Street",
                   "short_name" : "Yonge St",
                   "types" : [ "route" ]
                },
                {
                   "long_name" : "Willowdale",
                   "short_name" : "Willowdale",
                   "types" : [ "neighborhood", "political" ]
                },
                {
                   "long_name" : "North York",
                   "short_name" : "North York",
                   "types" : [ "political", "sublocality", "sublocality_level_1" ]
                },
                {
                   "long_name" : "Toronto",
                   "short_name" : "Toronto",
                   "types" : [ "locality", "political" ]
                },
                {
                   "long_name" : "Toronto Division",
                   "short_name" : "Toronto Division",
                   "types" : [ "administrative_area_level_2", "political" ]
                },
                {
                   "long_name" : "Ontario",
                   "short_name" : "ON",
                   "types" : [ "administrative_area_level_1", "political" ]
                },
                {
                   "long_name" : "Canada",
                   "short_name" : "CA",
                   "types" : [ "country", "political" ]
                },
                {
                   "long_name" : "M2N 5S3",
                   "short_name" : "M2N 5S3",
                   "types" : [ "postal_code" ]
                }
             ]
            }
       ],
       "status" : "OK"
}

感谢您的帮助。

Answer 1

以下 JSONPath 将起作用:

$..address_components[?(@.types[0] == 'country')].long_name

分解:

• $..address_components:关注address_components数组
• [?(@.types[0] == 'country')]:找到 address_components 子文档，其类型属性名为“type”，包含一个数组其中第一个值为“country”
• .long_name:返回本子文档的long_name属性。

使用 Jayway JsonPath Evaluator 验证在 Java 中:

JSONArray country = JsonPath.parse(json)
    .read("$..address_components[?(@.types[0] == 'country')].long_name");

// prints Canada
System.out.println(country.get(0));