java - 在Java中解析JSON数组

Question

我目前正在将 JSON 文件解析为我的 Java 程序，但遇到了问题。我得到一个 JSON 数组，如下所示:

[
  {
    "itemType": "magazineArticle",
    "creators": [
      {
        "firstName": "J. Antonio",
        "lastName": "Garcia-Macias",
        "creatorType": "author"
      },
      {
        "firstName": "Jorge",
        "lastName": "Alvarez-Lozano",
        "creatorType": "author"
      },
      {
        "firstName": "Paul",
        "lastName": "Estrada-Martinez",
        "creatorType": "author"
      },
      {
        "firstName": "Edgardo",
        "lastName": "Aviles-Lopez",
        "creatorType": "author"
      }
    ],
    "notes": [],
    "tags": [],
    "title": "Browsing the Internet of Things with Sentient Visors",
    "publicationTitle": "Computer",
    "volume": "44",
    "issue": "5",
    "ISSN": "0018-9162",
    "date": "2011",
    "pages": "46-52",
    "abstractNote": "Unlike the traditional Internet, the emerging Internet of Things constitutes a mix of virtual and physical entities. A proposed IoT browser enables the exploration of augmented spaces by identifying smart objects, discovering any services they might provide, and interacting with them.",
    "extra": "CICESE Research Center, Mexico; CICESE Research Center, Mexico; CICESE Research Center, Mexico; CICESE Research Center, Mexico",
    "libraryCatalog": "IEEE Computer Society"
  }
]

问题是我每次解析时都必须检查数组中是否包含名为“extra”的字段，因为每次解析时都不包含它。那么我该如何检查“extra”字段是否存在？

Answer 1

没有框架，您可以使用 org.json.* 中的 JSONObject 和 JSONArray。这是一个示例(未测试)。它将允许您检查额外键是否存在

String jsonAsString = "/*Your json as a String*/";
JsonArray jsonArray = new JSONArray(jsonAsString);

for(int i=0; i<jsonArray.length(); i++) {
    JSONObject jsonObject = jsonArray.getJSONObject(i);
    //Get values from your jsonObject
    jsonObject.has("extra"); //Check if extra is present
}