java中获取json中的数组转化为List＜E＞

java中获取json中的数组转化为List

//循环取到records的数值 for (int i = 0; i < records.size(); i++) {  Device item = JSONObject.parseObject(JSONObject.toJSONString(records.get(i)), Device.class);  //取到设备id  String id = item.getId();  //该字段是json数组这样获取  JSONArray alarmThreshold = JSONArray.parseArray(item.getAlarmThreshold());  //判空处理  if (alarmThreshold != null && alarmThreshold.size() > 0) {  //该字段为多个json数组虚幻取出单个      for (int h = 0; h < alarmThreshold.size(); h++) {      //获取到该字段全部数值   String alarmThresholds = String.valueOf(JSONObject.parseObject(alarmThreshold.getString(h)).get("data"));   //此处存入到list中   List<AlarmThresholdData> alarmThresholdData = JSONObject.parseObject(alarmThresholds, ArrayList.class);   //alarmThresholdData 此处改字段已经是单个data，循环遍历该单个data   for (int a = 0; a < alarmThresholdData.size(); a++) {AlarmThresholdData items = JSONObject.parseObject(JSONObject.toJSONString(alarmThresholdData.get(a)), AlarmThresholdData.class);//取出该json字段中具体属性值String alarmLvId = items.getAlarmLvId();String value = items.getValue();String conditional = items.getConditional();

重要方法转：
获取到的json字段数据库为json数组

JSONArray alarmThreshold = JSONArray.parseArray(item.getAlarmThreshold());

对该数组进行判空处理，继续循环遍历。取出json数组单个json数据。存入到list中

 if (alarmThreshold != null && alarmThreshold.size() > 0) {      for (int h = 0; h < alarmThreshold.size(); h++) {   String alarmThresholds = String.valueOf(JSONObject.parseObject(alarmThreshold.getString(h)).get("data"));   List<AlarmThresholdData> alarmThresholdData = JSONObject.parseObject(alarmThresholds, ArrayList.class);

循环遍历该List取出Json数组里面具体的单个字段值

  for (int a = 0; a < alarmThresholdData.size(); a++) {AlarmThresholdData items = JSONObject.parseObject(JSONObject.toJSONString(alarmThresholdData.get(a)), AlarmThresholdData.class);String alarmLvId = items.getAlarmLvId();String value = items.getValue();String conditional = items.getConditional();

科普知事网