java - Java json-path 库的问题

Question

全部。我遇到了一个非常奇怪的问题 https://github.com/json-path/JsonPath

问题之一似乎是实现中的可重入问题:执行路径时，每个部分返回一个字符串:

Expected to find an object with property ['ModuleListResponse'] in path $[0]['response'] but found 'java.lang.String'. This is not a json object according to the JsonProvider: 'com.jayway.jsonpath.spi.json.JsonSmartJsonProvider'.

我通过将 JSONObject/JSONArray 传递给 JsonPath.read() 而不是 JSON 字符串来“破解”它。这样做之后，现在我得到:

Filter: [0]['name'] can only be applied to arrays. Current context is: [{"startLocation":{"types":["city"],"address":"Argentina","latitude":-34.6075682,"name":"Buenos Aires","description":"Buenos Aires is the capital and largest city of Argentina. The city is located on the western shore of the estuary of the Río de la Plata, o...449a049a781"}}]

如您所见，这已经是一个数组了。我已经用谷歌搜索了很多，但找不到问题所在。

关于解析它的代码，你已经有了:

    jsonString = StringUtils.trim(jsonString);
    if (jsonString.startsWith("[")) {
        jsonObject = new org.json.JSONArray(jsonString);
    } else {
        jsonObject = new JSONObject(jsonString);
    }
    String jsonPath = "$[0].name";
    Object jsonResult = JsonPath.using(conf)
                             .parse(jsonObject)
                             .read(jsonPath);

所以，问题是:为什么 JsonPath 将 json 读取为字符串，而不是 json？对于第二个问题，当它显然是一个数组时，为什么不将其作为数组。

Answer 1

如果将 JSON 格式设置为易于阅读的格式，您会发现属性路径不正确。这是实际的 JSON:

[
  {
  "startLocation": 
    {
      "types": ["city"],
      "address": "Argentina",
      "latitude": -34.6075682,
      "name": "Buenos Aires",
      "description": "Buenos Aires is the capital and largest city of Argentina. The city is located on the western shore of the estuary of the Río de la Plata, o...449a049a781"
    }
  }
]

您正在尝试访问$.[0].name，但该值不存在。

$.[0] 是

{
    "startLocation": {
      "types": ["city"],
      "address": "Argentina",
      "latitude": -34.6075682,
      "name": "Buenos Aires",
      "description": "Buenos Aires is the capital and largest city of Argentina. The city is located on the western shore of the estuary of the Río de la Plata, o...449a049a781"
}

$.[0] 的唯一顶级键是 startLocation，因此您实际要查找的是

$.[0].startLocation.name

我建议撤消您添加的 JSONArray 和 JSONObject 绒毛，因为它可能掩盖了真正的问题，这只是一个无效的属性路径。