用OkHttpGo和FastJson获取OneNET云平台数据(解析嵌套数组)

JSON数据格式有两种,一种是 { } 大括号表示的JSON对象,一种是 [ ] 中括号表示的JSON数组。从OneNET获取到的数组是这样的,并用Json解析网址查看https://jsonformatter.curiousconcept.com/#(图1)。可以看到这是一个对象包含了数组又包含对象的JSON数据。比如我现在要获取id号为3300_1_5700时间为2020-12-09 20:19:30.624的数据(图1唯一展开的datastreams数组元素)它是一个JSON对象(因为它是被一个大括号包者的),所以datastreams[0]这个JSON对象时包含了datapoints和id,前者又是一个JSON数组(中括号包者),后者则是一个普通的字符串。综上,要获取图1的value值,我要通过一开始返回到的JSON数据 找到 dataJSON对象 找到 datastreamsJSON数组 找到 datapointsJSON数组 中的value字符串。 

```

{ "errno": 0, "data": { "count": 10, "datastreams": [ { "datapoints": [ { "at": "2020-12-09 20:19:30.624", "value": 0 } ], "id": "3300_1_5700" }, { "datapoints": [ { "at": "2019-07-30 21:38:03.729", "value": 0 } ], "id": "3327_0_5700" }, { "datapoints": [ { "at": "2019-12-26 21:27:14.700", "value": "\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000" } ], "id": "3336_0_5514" }, { "datapoints": [ { "at": "2019-12-26 21:27:14.700", "value": "\u0000\u0000\u0000\u0000\u0000\u0000\u0000\u0000" } ], "id": "3336_0_5515" }, { "datapoints": [ { "at": "2020-12-09 20:19:30.624", "value": 0 } ], "id": "3303_0_5700" }, { "datapoints": [ { "at": "2019-04-21 14:35:11.158", "value": 29.8 } ], "id": "3304_0_5700" }, { "datapoints": [ { "at": "2020-12-09 20:19:31.980", "value": 0 } ], "id": "3326_0_5700" }, { "datapoints": [ { "at": "2019-12-26 19:23:09.191", "value": false } ], "id": "3338_0_5850" }, { "datapoints": [ { "at": "2020-12-09 20:19:29.412", "value": 0 } ], "id": "3300_0_5700" }, { "datapoints": [ { "at": "2019-05-17 09:09:13.681", "value": false } ], "id": "3311_0_5850" } ] }, "error": "succ" }

```

 

            (图1)

执行过程是,当获取到data JSON对象时,获取count字符串,这是OneNET平台给我返回的数值,功能时告诉我datastreams中一共有多少个元素,所以用遍历datastreams数组,进入datastreams后,获取id号,id号是用单片机根据NB-IoT文档(OneNET官网文档)上传到云平台的,根据这一id号来确认到底是哪一个传感器。总之什么时候用getJSONObject或getJSONaRRAY一定要看自己返回的数据是什么,是大括号还是中括号,如果都不是只是一个普通的字符串就用getString方法获取字符串,getString("value")中""写的是元素名,拿的是元素值,比如"value":0这一行,拿的就是0这个元素值。

  1 package com.example.helloworld.learnokhttp;
  2 
  3 import android.bluetooth.BluetoothClass;
  4 import android.os.Bundle;
  5 import android.view.View;
  6 import android.widget.Button;
  7 import android.widget.TextView;
  8 import android.widget.Toast;
  9 
 10 import androidx.annotation.Nullable;
 11 import androidx.appcompat.app.AppCompatActivity;
 12 
 13 import com.alibaba.fastjson.JSON;
 14 import com.alibaba.fastjson.JSONArray;
 15 import com.alibaba.fastjson.JSONObject;
 16 import com.example.helloworld.R;
 17 import com.example.helloworld.learnokhttp.javabean.Data;
 18 import com.example.helloworld.learnokhttp.javabean.Datapoints;
 19 import com.example.helloworld.learnokhttp.javabean.Datastreams;
 20 import com.example.helloworld.learnokhttp.javabean.JsonRootBean;
 21 import com.lzy.okgo.OkGo;
 22 import com.lzy.okgo.adapter.Call;
 23 import com.lzy.okgo.cache.CacheMode;
 24 import com.lzy.okgo.callback.StringCallback;
 25 import com.lzy.okgo.model.Response;
 26 
 27 import org.w3c.dom.Text;
 28 
 29 import java.util.Iterator;
 30 import java.util.List;
 31 
 32 public class OkHttpGoActivity extends AppCompatActivity implements View.OnClickListener {
 33 
 34     private String url = "https://api.heclouds.com/devices/523698851/datapoints";//
 35     private Button btn_get,btn_resolvebyfastjson;
 36     private TextView tv_result,tv_wendu,tv_do,tv_ph,tv_tds,tv_zhuodu;
 37 
 38     @Override
 39     protected void onCreate(@Nullable Bundle savedInstanceState) {
 40         super.onCreate(savedInstanceState);
 41         setContentView(R.layout.activity_okhttpgo);
 42 
 43         setTitle("用封装的方法获取数据");
 44 
 45         btn_get = findViewById(R.id.btn_get);
 46         btn_resolvebyfastjson = findViewById(R.id.btn_resolvebyfastjson);
 47         tv_result = findViewById(R.id.tv_result);
 48         tv_wendu = findViewById(R.id.tv_wendu);
 49         tv_do = findViewById(R.id.tv_do);
 50         tv_ph = findViewById(R.id.tv_ph);
 51         tv_tds = findViewById(R.id.tv_tds);
 52         tv_zhuodu = findViewById(R.id.tv_zhuodu);
 53         btn_get.setOnClickListener(this);
 54         btn_resolvebyfastjson.setOnClickListener(this);
 55     }
 56 
 57     @Override
 58     protected void onDestroy() {
 59         super.onDestroy();
 60         //Activity销毁时,取消网络请求
 61         OkGo.getInstance().cancelTag(this);
 62     }
 63 
 64     /**
 65      *先用okhttpgo拿一次数据
 66      *@author home
 67      *@time 2021/2/24 10:23
 68     */
 69     private void getByOkGo() {
 70         OkGo.<String>get(url)//文档说的第一行泛型一定要添加是指这里
 71                 .headers("api-key", "4VdbaFeRQZRwaSTWNhWxb2UEHaw=")//设备的api-key
 72                 .headers("Content-Type","application/json")
 73                 .tag(this)
 74                 .execute(new StringCallback() {
 75                     @Override
 76                     public void onSuccess(Response<String> response) {//请求成功回调onSuccess方法
 77                         tv_result.setText(response.body());//文档中有说明,body是返回的数据
 78                     }
 79 
 80                     @Override
 81                     public void onError(Response<String> response) {
 82                         Toast.makeText(getApplicationContext(), "接口请求错误!", Toast.LENGTH_LONG).show();
 83                     }
 84                 });
 85     }
 86 
 87     /**
 88      *OkHttpGo与FastJson结合,并显示到界面
 89      *@author home
 90      *@time 2021/2/24 10:25
 91     */
 92     private void jsonToJavaListByFastJson() {
 93         OkGo.<String>get(url)//文档说的第一行泛型一定要添加是指这里
 94                 .headers("api-key", "4VdbaFeRQZRwaSTWNhWxb2UEHaw=")//设备的api-key
 95                 .headers("Content-Type","application/json")
 96                 .tag(this)
 97                 .execute(new StringCallback() {
 98                     @Override
 99                     public void onSuccess(Response<String> response) {//请求成功回调onSuccess方法
100 
101                         String value = "", id = "";
102                         int count = 0;
103 
104                         JSONObject jsonObjectData = JSONObject.parseObject(response.body()).getJSONObject("data");//获取json对象后再获取json对象,即第二层data
105                         count = jsonObjectData.getIntValue("count");//count是Datastreams数组的下标值
106                         JSONArray jsonArrayDatastreams = jsonObjectData.getJSONArray("datastreams");//获取json数组即datastearms
107 
108                         for(int j = 0; j < count; j++) {//遍历Datastreams数组
109                             JSONObject jsonObjectIndex = jsonArrayDatastreams.getJSONObject(j);
110                             id = jsonObjectIndex.getString("id");
111                             JSONArray jsonArrayDatapoints = jsonObjectIndex.getJSONArray("datapoints");
112                             JSONObject jsonObjectValue = jsonArrayDatapoints.getJSONObject(0);//Datapoints数组只有一个元素(对象),所以下标是1
113                             value = jsonObjectValue.getString("value");
114                             switch (id) {
115                                 case "3303_0_5700":    //温度
116                                     //System.out.println("温度" + value + id);
117                                     tv_wendu.setText("温度" + value + "\t设备号" + id);
118                                     break;
119                                 case "3300_0_5700":     //溶解氧
120                                     //System.out.println("DO" + value + id);
121                                     tv_do.setText("溶解氧" + value + "\t设备号" + id);
122                                     break;
123                                 case "3327_0_5700":     //电导率
124                                     //System.out.println("电导率" + value + id);
125                                     tv_tds.setText("TDS" + value + "\t设备号" + id);
126                                     break;
127                                 case "3326_0_5700":     //ph
128                                     //System.out.println("ph" + value + id);
129                                     tv_ph.setText("PH" + value + "\t设备号" + id);
130                                     break;
131                                 case "3300_1_5700":     //浊度
132                                     //System.out.println("浊度" + value + id);
133                                     tv_zhuodu.setText("浊度" + value + "\t设备号" + id);
134                                     break;
135                             }
136                         }
137                     }
138 
139                     @Override
140                     public void onError(Response<String> response) {
141                         Toast.makeText(getApplicationContext(), "接口请求错误!", Toast.LENGTH_LONG).show();
142                     }
143                 });
144 
145     }
146 
147     @Override
148     public void onClick(View view) {
149         switch (view.getId()) {
150             case R.id.btn_get: //使用原生的okhttp请求网络数据
151                 getByOkGo();//用okgo方法获取数据
152                 break;
153             case R.id.btn_resolvebyfastjson:
154                 jsonToJavaListByFastJson();
155                 break;
156         }
157     }
158 
159 
160 }

 布局文件

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:orientation="vertical" android:layout_width="match_parent"
 4     android:layout_height="match_parent">
 5 
 6     <Button
 7         android:id="@+id/btn_get"
 8         android:layout_width="match_parent"
 9         android:layout_height="wrap_content"
10         android:text="get方法获取数据"
11         android:textAllCaps="false"/>
12 
13     <Button
14         android:id="@+id/btn_resolvebyfastjson"
15         android:layout_width="match_parent"
16         android:layout_height="wrap_content"
17         android:text="通过fastjson解析"
18         android:textAllCaps="false"/>
19 
20     <TextView
21         android:id="@+id/tv_result"
22         android:layout_width="match_parent"
23         android:layout_height="wrap_content"/>
24 
25 
26     <TextView
27         android:id="@+id/tv_wendu"
28         android:layout_width="match_parent"
29         android:layout_height="wrap_content"/>
30 
31     <TextView
32         android:id="@+id/tv_do"
33         android:layout_width="match_parent"
34         android:layout_height="wrap_content"/>
35 
36     <TextView
37         android:id="@+id/tv_ph"
38         android:layout_width="match_parent"
39         android:layout_height="wrap_content"/>
40 
41     <TextView
42         android:id="@+id/tv_tds"
43         android:layout_width="match_parent"
44         android:layout_height="wrap_content"/>
45 
46     <TextView
47         android:id="@+id/tv_zhuodu"
48         android:layout_width="match_parent"
49         android:layout_height="wrap_content"/>
50 
51 </LinearLayout>

最后的效果(图2)

 

 

           (图2)

       

posted on 2021-02-24 11:12  stuMartin  阅读(82)  评论(0编辑  收藏  举报

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