在 java 中出现错误 JSONObject 无法转换为 JSONArray？

Question

i need some help to fix this issue, I am having: java.lang.ClassCastException: org.json.simple.JSONObject cannot be cast to org.json.simple.JSONArray . I tried by wrapping [] over my jsonobject but that did not work. can anyone help me solve this issue with my code below. thank you!

here is my code:

 JSONParser parser = new JSONParser();
jsonArray = (JSONArray) parser.parse(response);


JSONObject jsonObject;
jsonObject = (JSONObject) jsonArray.get(0);
String email = jsonObject.get("EmailAddress").toString();

Answer 1

The standard JSON library from json.org for java is designed for dynamic languages and as a consequence absolutely sucks on java. Don't use it; get something like Jackson or GSON instead.

The problem is that whatever JSON you have isn't an array, it's for example {data: [{a: 1}, {b: 2}]} , which is sensible, as JSON technically implies that the 'top-level' thing MUST be an object or it isn't considered valid, even though many, many, many usages and implementations flaunt that rule (JSON has the rather significant downside of everyone piling on addendums and caveats on top of a simple standard, unfortunately. Rolling with those punches is part of the job).

In other words, parser.parse(response) is returning a JSONObject because you're parsing a, well, JSON object: a thing in {} , not in [] . Given that you haven't pasted your actual JSON, Who knows what that means. Possibly there's only one element being sent to you, eg you want:

// JSON looks like:
// {"EmailAddress": "something@somewhere"}
JSONParser parser = new JSONParser();

JSONObject jsonObject = (JSONObject) parser.parse(response);
String email = jsonObject.get("EmailAddress").toString();

Or possibly the output array is itself wrapped in a JSON object with a single value, eg you want:

// JSON looks like:
// {"data": [{"EmailAddress": "something@somewhere"}]}

JSONParser parser = new JSONParser();
JSONObject main = (JSONObject) parser.parse(response);
jsonArray = main.getJSONArray("data");

JSONObject jsonObject;
jsonObject = (JSONObject) jsonArray.get(0);
String email = jsonObject.get("EmailAddress").toString();

Actually, you don't want either of those, you want to delete that and read a tutorial on Jackson or GSON instead.