Question

我有以下JSON文件：

{
   “weight": {
      "type": "weight",
      "range": [
         "2016-02-15",
         "2016-02-16",
         "2016-02-17",
         "2016-02-18",
         "2016-02-19",
         "2016-02-20",
         "2016-02-21"
      ],
      "days": [
         {
            "weight": [
               {
                  "bmi": 29.5,
                  "date": "2016-02-14",
                  "logId": 1455494399000,
                  "source": "API",
                  "time": "23:59:59",
                  "weight": 90.3
               },
      ]
}

然后我将以下类添加到JSON中。

public class fitbitTypeWeight {
    public fitbitDays weight;
}

public class fitbitDays {
    public fitbitDayWeight days;
}

public class fitbitDayWeight {
    public fitbitWeight weight;
}

public class fitbitDayWeight {
    public fitbitWeight weight;
}

然后，我有以下代码尝试解析它。

public static void readJSON() {
    Gson gson = new Gson();  
    type = gson.fromJson(file, fitbitTypeWeight.class);
    GsonBuilder builder = new GsonBuilder();
    gson = builder.create();
    createFitBitInfo();
}

private static void createFitBitInfo() throws ITrustException{
    RemoteMonitoringDAO db = new RemoteMonitoringDAO(prodDAO);
    RemoteMonitoringDataBean temp=new RemoteMonitoringDataBean();
    fitbitDayWeight info = type.weight.days;
    temp.setFitbitWeight(info.weight.weight);
    temp.setFitbitDate(info.weight.date);
    temp.setLoggedInMID(userID);
    db.storeFitbitData(temp);
}

但是，我在fitbitDayWeight上获得了一个NPE异常信息= type.weight.days;

关于可能出现什么问题的任何建议？

Answer 1

您的JSON格式不正确。仅查看days元素，我们有：

"days": [
  {
    "weight": [
      {
        "bmi": 29.5,
        "date": "2016-02-14",
        "logId": 1455494399000,
        "source": "API",
        "time": "23:59:59",
        "weight": 90.3
      },
]

看着，你得到了：

悬挂,列表weight
列表]

weight

列表}

0

days

（要完成，如果最终,不存在，]将关闭weight，然后}将关闭列表0 {1}}，留下days并且基础未公开。）

此外，您的第一个引号代替days “。我不确定GSON是否可以使用角度引号，但我知道JSON标准要求所有引号都为"。

老实说，我很遗憾GSON没有因此而吐出错误。但是你获得NullPointerException的原因是因为"被设置为默认值，因为GSON无法读取它的值。

来自JSON的GSON嵌套对象空指针异常

1 个答案: