java如何在Android中解析json对象？

Question

我试图解析Json对象，它是

{
   "results":[
      {
         "face":{
            "id":361122.0,
            "photo_hash":"0a2aaff34fd576fc1caf711d88cbfd53",
            "x1":699,
            "x2":1020,
            "y1":271,
            "photo":" ",
            "thumbnail":" ",
            "meta":"",
            "timestamp":"2016-07-28T08:50:43.710183",
            "y2":592
         },
         "confidence":0.93187
      },
      {
         "face":{
            "id":361260.0,
            "photo_hash":"767bf4df0c8a04361aaf5e6b74eb4d8c",
            "x1":-25,
            "x2":147,
            "y1":10,
            "photo":" ",
            "thumbnail":" ",
            "meta":"",
            "timestamp":"2016-07-28T15:13:09.086390",
            "y2":165
         },
         "confidence":0.926754
      }
   ]
}

我使用这样的代码来解析confidence和thumbnail：

resultParams[i].confidence = jsonObject.getJSONArray("results").getJSONObject(i).getString("confidence");

resultParams[i].thumbnail = jsonObject.getJSONArray("results").getJSONObject(i).getJSONObject("face").getString("thumbnail");

然而，它给出了例外"java.lang.NullPointerException: Attempt to write to field on a null object reference"

你能帮我成功解析它吗

Answer 1

如果您知道将接收什么类型的json对象（或者您可能有一个API），您可以通过例如Jackson library来创建此类对象。然后用它的getter访问“face”对象

yourObject.getResults().get(i).getFace().getThumbnail();