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解析json数据

解析从服务器返回的json数据
这阵子在做一个天气预报的demo，使用百度天气的api获取json数据进行解析。json数据如下

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{
  "error": 0,
  "status": "success",
  "date": "2015-10-01",
  "results": [
    {
      "currentCity": "nanjing",
      "pm25": "76",
      "index": [
        {
          "title": "穿衣",
          "zs": "舒适",
          "tipt": "穿衣指数",
          "des": "建议着长袖T恤、衬衫加单裤等服装。年老体弱者宜着针织长袖衬衫、马甲和长裤。"
        },
        {
          "title": "洗车",
          "zs": "较不宜",
          "tipt": "洗车指数",
          "des": "较不宜洗车，未来一天无雨，风力较大，如果执意擦洗汽车，要做好蒙上污垢的心理准备。"
        },
        {
          "title": "旅游",
          "zs": "适宜",
          "tipt": "旅游指数",
          "des": "天气较好，温度适宜，是个好天气哦。这样的天气适宜旅游，您可以尽情地享受大自然的风光。"
        },
        {
          "title": "感冒",
          "zs": "较易发",
          "tipt": "感冒指数",
          "des": "昼夜温差较大，较易发生感冒，请适当增减衣服。体质较弱的朋友请注意防护。"
        },
        {
          "title": "运动",
          "zs": "适宜",
          "tipt": "运动指数",
          "des": "天气较好，赶快投身大自然参与户外运动，尽情感受运动的快乐吧。"
        },
        {
          "title": "紫外线强度",
          "zs": "中等",
          "tipt": "紫外线强度指数",
          "des": "属中等强度紫外线辐射天气，外出时建议涂擦SPF高于15、PA+的防晒护肤品，戴帽子、太阳镜。"
        }
      ],
      "weather_data": [
        {
          "date": "周四 10月01日 (实时：15℃)",
          "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/duoyun.png",
          "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/duoyun.png",
          "weather": "多云",
          "wind": "西北风4-5级",
          "temperature": "23 ~ 14℃"
        },
        {
          "date": "周五",
          "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/qing.png",
          "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/qing.png",
          "weather": "晴",
          "wind": "东南风微风",
          "temperature": "24 ~ 14℃"
        },
        {
          "date": "周六",
          "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/duoyun.png",
          "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/duoyun.png",
          "weather": "多云",
          "wind": "东风微风",
          "temperature": "24 ~ 17℃"
        },
        {
          "date": "周日",
          "dayPictureUrl": "http://api.map.baidu.com/images/weather/day/yin.png",
          "nightPictureUrl": "http://api.map.baidu.com/images/weather/night/yin.png",
          "weather": "阴",
          "wind": "东风3-4级",
          "temperature": "24 ~ 19℃"
        }
      ]
    }
  ]
}

发送请求

网络请求需要在非主线程中使用，避免拥塞

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public void getWeatherInfo()
    {
        new Thread(new Runnable() {
            @Override
            public void run()
            {
                try
                {
                    HttpClient httpClient = new DefaultHttpClient();
                    location = "南京";
                    url = "http://api.map.baidu.com/telematics/v3/weather?location="+location+"&output=json&ak=gVdU1hNhSplDXKmdLtoRvK0O";
                    HttpGet httpGet = new HttpGet(url);
                    HttpResponse httpResponse = httpClient.execute(httpGet);
                    if (httpResponse.getStatusLine().getStatusCode()==200)
                    {
                        Log.d(TAG,"服务器返回的代码为 "+httpResponse.getStatusLine().getStatusCode());
                        Log.d(TAG,"获取json成功");
                        HttpEntity entity = httpResponse.getEntity();
                        String response = EntityUtils.toString(entity, "UTF-8");

                        //调用解析
                        Log.d(TAG,"获取到的数据 "+response);
                        //创建对象调用解析方法
                        ParseJson parseJson = new ParseJson();
                        parseJson.parseJsonWithGson(response);
                        parseJson.parseJson(response);
                    }
                }
                catch (Exception e)
                {e.printStackTrace();}

            }
        }).start();
    }

解析数据

使用原生

先获取三个对象，error、status和date
再通过数组遍历results中的对象，以此类推将数组中的所有数据取出

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public void parseJson(String jsonData)
    {
        try
        {
            Log.d(TAG,"解析json数据");
            JSONObject jsonObject = new JSONObject(jsonData);
            Log.d(TAG,"error is "+jsonObject.get("error"));
            Log.d(TAG,"status is "+jsonObject.get("status"));
            Log.d(TAG,"date is "+jsonObject.get("date"));
            //找到今天的日期
            String strGetDate = jsonObject.get("date").toString();
            String regExGetDate = "(\\d{4})-(\\d{2})-(\\d{2})";
            Pattern patternGetDate = Pattern.compile(regExGetDate);
            Matcher matcherGetDate = patternGetDate.matcher(strGetDate);
            boolean isFindDate = matcherGetDate.find();
            final String date = matcherGetDate.group();
            Log.d(TAG,"是否找到日期 "+isFindDate);
            Log.d(TAG,"今天日期是 "+date);

            JSONArray resultsJsonArray = jsonObject.getJSONArray("results");//遍历results
            for (int i = 0;i<resultsJsonArray.length();i++)
            {
                org.json.JSONObject jsonObjectInResults = resultsJsonArray.getJSONObject(i);
                Log.d(TAG,"pm25 is "+jsonObjectInResults.get("pm25"));

                String currentCity = jsonObjectInResults.get("currentCity").toString();
                Log.d(TAG,"currentCity is "+currentCity);
            }
          }catch (Exception e)
        {
            e.printStackTrace();
        }
      }

使用Gson

Gson 是Google 的一个解析json的库，使用起来比 org.json.JSONArray 和 org.json.JSONObject 简便一些

首先需要定义一个类

类中的成员变量必须和json中的 key 是一样的，变量类型也要相互对应

  • 解析单个对象
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{
    "name": "PPTing",
    "age": 21,
}

对应的类应该这么定义

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public class Person
{
  public String name;
  public int age;
}
  • 解析嵌套对象
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{
  "name":"PPTing",
  "age":21,
  "other":{
    "email":"i@ppting.me",
    "location":"nanjing"
  }
}

对应的类应该这么定义

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public class Person
{
  public String name;
  public int age;
  public Other other;
  public static class Other
  {
    public String email;
    public String location;
  }
}
  • 解析数组
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{
    "name": "PPTing",
    "age": 21,
    "results":[
    "email":"i@ppting.me",
    "location":"nanjing"
    ]
}

对应的类应该这么定义

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public class Person
{
  public String name;
  public int age;
  public List<Results> results = new ArrayList<Results>();
  public static class Results
  {
    public String email;
    public String location;
  }
}

然后再在类中加入set和get方法 在Android Studio 中添加set 和 get 方法的快捷键是 command + N

####开始解析

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public void parseJsonWithGson(String jsonData)
{
        Log.d(TAG,"用gson进行解析");
        Gson gson = new Gson();
        Person person = gson.fromJson(jsonData,Person.class);
        Log.d(TAG,"email is "+person.getEmail());
}

这样就可以获取到email 的值

这里贴上用来解析文章开头的天气json的代码

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package me.ppting.weather;

import android.util.Log;

import java.util.ArrayList;
import java.util.List;

/**
 * Created by PPTing on 15/9/22.
 */
public class WeatherInfo
{
    private String error;
    private String status;
    private String date;
    public String getError() {return error;}
    public void  setError(String error) {this.error = error;}
    public String getStatus() {return status;}
    public void setStatus(String status) {this.status = status;}
    public String getDate(){return date;}
    public void setDate(String date){this.date = date;}


    public List<Results> results = new ArrayList<Results>();
    public List<Results> getResults(){return results;}
    public void setresults(List<Results> results){this.results = results;}
    public static class Results
    {
        public String currentCity;
        public String pm25;

        public List<Index> getIndex() {
            return index;
        }

        public void setIndex(List<Index> index) {
            this.index = index;
        }

        public List<Index> index = new ArrayList<Index>();

        public List<Weather_data> getWeather_data() {
            return weather_data;
        }

        public void setWeather_data(List<Weather_data> weather_data) {
            this.weather_data = weather_data;
        }

        private List<Weather_data> weather_data = new ArrayList<Weather_data>();
        //get and set
        public String getCurrentCity(){return currentCity;}
        public void setCurrentCity(String currentCity){this.currentCity = currentCity;}
        public String getPm25(){return pm25;}
        public void setPm25(String pm25){this.pm25 = pm25;}
        public static class Index
        {
            private String title;
            private String zs;
            private String des;
            private String tipt;

            public String getTitle(){return title;}
            public void setTitle(String title){this.title = title;}
            public String getZs(){return zs;}
            public void setZs(String zs){this.zs = zs;}
            public String getTipt() {return tipt;}
            public void setTipt(String tipt) {this.tipt = tipt;}
            public String getDes() {return des;}
            public void setDes(String des) {this.des = des;}

        }
        public class Weather_data
        {
            private String data;
            private String dayPictureUrl;
            private String nightPictureUrl;
            private String weather;
            private String wind;
            private String temperature;

            public String getData() {
                return data;
            }

            public void setData(String data) {
                this.data = data;
            }

            public String getDayPictureUrl() {
                return dayPictureUrl;
            }

            public void setDayPictureUrl(String dayPictureUrl) {
                this.dayPictureUrl = dayPictureUrl;
            }

            public String getNightPictureUrl() {
                return nightPictureUrl;
            }

            public void setNightPictureUrl(String nightPictureUrl) {
                this.nightPictureUrl = nightPictureUrl;
            }
            public String getWeather() {return weather;}
            public void setWeather(String weather) {
                this.weather = weather;
            }
            public String getWind() {
                return wind;
            }
            public void setWind(String wind) {
                this.wind = wind;
            }
            public String getTemperature() {
                return temperature;
            }
            public void setTemperature(String temperature) {
                this.temperature = temperature;
            }
        }
    }
}

参考：
Stackoverflow

Android gson
通过Gson解析Json数据
Android中使用Gson解析稍复杂的JSON数据

这里有两个小工具：

Tips：
[]: 定义成一个List
{}: 定义成一个类

解析json数据

https://ppting.me/2015/10/02/2015_10_02_parse_json/

作者

PPTing

发布于

2015-10-02

更新于

2022-02-12

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