java - jsonObject.has()是干嘛的?

Question

jsonObject.has()是干嘛的?

  String jsonStr=new String(data);
        try {
            JSONObject jsonObject=new JSONObject(jsonStr);

            if (jsonObject.has("fileUri")){
            }


        } catch (JSONException e) {
            e.printStackTrace();
        }

Answer 1

Determine if the JSONObject contains a specific key.
Parameters:
key A key string.
Returns:
true if the key exists in the JSONObject.

    public boolean has(String key) {
         return this.map.containsKey(key);
    }
    
    public JSONObject() {
        this.map = new HashMap<String, Object>();
    }

It can be seen that the judgment is made by using the Map.containsKey(key) method.

Answer 2

Answer 3

Determine whether there is a certain field in the class

Answer 4

Query whether the object contains the key and return boolean, which is consistent with the usage of Map.containsKey(key)