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数据解析2:JSON解析(1)

　　JSON是网络传输中数据组织的一种格式。

　　下面为几个不同的JSON数据：

　　1."{name:'jack',age:23}"

　　2."{student:{name:'jack',age:23}}"

　　3."{students:[{name:'jack',age:23},{name:'lily',age:22}]}"

　　4."{object:{persons:[{name:'呵呵',image:'http://192.168.56.1:8080/Web/ok.jpg'},{name:'哈哈',image:'http://192.168.56.1:8080/Web/s1.png'},{name:'嘿嘿',image:'http://192.168.56.1:8080/Web/s2.jpg'}]}}"

　　5."[{school:'pku',good:'false',class:{name:'android',count:40}},{school:'pku',good:'true',class:{name:'ios',count:45}}]"

　　6."{status:2,result:[{company_name:'pku1',company_id:1}, {company_name:'pku2',company_id:5},{company_name:'pku3',company_id:7}]}"

　　　　对于JSON数据的第一印象:JSON数据就是字符串,且包含在大括号之间，且字符串中的数据是有一定结构的，而且每一部分数据好像采用的是键值映射的关系。

　　JSON的简单介绍:

　　大概总结下，就是JSON字符串，是包含在大括号里，组织数据有两种方式，一是键值对，二是数组，通过这两种，采用符合规范的结构，你可以自己写出任意自定义任意长的JSON数据，检查一个JSON数据是否正确，可以通过一个网址http://www.bejson.com/,输入你自己写的json字符串，它可以帮你校验。

　　那么如何解析JSON字符串呢？

　　进行解析，首先要导入一个JSON解析相关的jar包(在Android开发下这个包已经自动导入了，而Java中需要下载并导入包)，这个包下有两个重要的类，分别是JSONObject和JSONArray，分别与上面讲的键值对和数组一一对应。

　　下面是解析几个简单JSON字符串的例子，可以很好帮助入门JSON解析：

1 String json = "{name:'Jack',age:20,address:'beijing'}"；
2 
3 JSONObject object = new JSONObject(json);
4 
5 String name = object.getString("name");
6 int age = object.getInt("age");
7 String address = object.getString("address");        
8 System.out.println(name+","+age+","+address);

1 String json = "{student:{address:'beijing',age:18,name:'Lucy'}}";
2         
3 JSONObject obj = new JSONObject(json);
4 JSONObject object = obj.getJSONObject("student");
5         
6 String address = object.getString("address");
7 int age = object.getInt("age");
8 String name = object.getString("name");    
9 System.out.println(address+","+age+","+name);

 1 String json = "{students:[{address:'shanghai',age:23,name:'xiaobai'},{address:'shenzhen',age:24,name:'xiaohei'}]}";
 2         
 3         JSONObject object  = new JSONObject(json);
 4         JSONArray array = object.getJSONArray("students");
 5         
 6         //遍历数组，得到每个对象
 7         for(int i=0;i<array.length();i++)
 8         {
 9             JSONObject obj = array.getJSONObject(i);
10             String address = obj.getString("address");
11             int age = obj.getInt("age");
12             String name = obj.getString("name");
13             System.out.println(address+","+age+","+name);
14         }

 1 String json = "{object:{persons:[{name:'呵呵',image:'http://192.168.56.1:8080/Web/ok.jpg'},{name:'哈哈',image:'http://192.168.56.1:8080/Web/s1.png'},{name:'嘿嘿',image:'http://192.168.56.1:8080/Web/s2.jpg'}]}}";
 2 
 3          JSONObject object = new JSONObject(json);
 4          
 5          JSONObject obj = object.getJSONObject("object");
 6          
 7          JSONArray array = obj.getJSONArray("persons");
 8          
 9          for(int i=0;i<array.length();i++)
10          {
11              JSONObject jsonObj = array.getJSONObject(i);
12              
13              String name = jsonObj.getString("name");
14              String image = jsonObj.getString("image");
15              System.out.println(name+","+image);
16              
17          }

 1 String json="[{school:'bpk1',good:'false',class:{name:'android',count:40}},{school:'pku2',good:'true',class:{name:'ios',count:45}}]";
 2 
 3         JSONArray array = new JSONArray(json);
 4         
 5         for(int i=0;i<array.length();i++)
 6         {
 7             JSONObject obj = array.getJSONObject(i);
 8             String school = obj.getString("school");
 9             String good = obj.getString("good");
10             JSONObject object = obj.getJSONObject("class");
11             String name = object.getString("name");
12             int count = object.getInt("count");
13             
14             System.out.println(school+","+good+","+name+","+count);
15         }

 1 String json="{status:2,result:[{company_name:'pku1',company_id:1}, {company_name:'pku2',company_id:5},{company_name:'pku3',company_id:7}]}";
 2 
 3         
 4         JSONObject object = new JSONObject(json);
 5         String status = object.getString("status");
 6         System.out.println(status);
 7         
 8         JSONArray array = object.getJSONArray("result");
 9         for(int i=0;i<array.length();i++)
10         {
11             JSONObject obj = array.getJSONObject(i);
12             String comName = obj.getString("company_name");
13             int comId = obj.getInt("company_id");
14             
15             System.out.println(comName+","+comId);
16         }

　　总结以上:关于JSON数据的解析，无非就是JSONObject和JSONArray根据实际的JSON字符串的结构灵活使用，当获取的是对象，使用的是JSONObject，当获取的是一个数组，使用的是JSONArray，让后取出数据总是从JSONObject中根据键取出相对应的数据。

　　示例:看一个比较复杂的例子，从网络上获取JSON字符串，然后解析出来

 1 {
 2     "cityname": "双鸭山",
 3     "citycode": "101051301",
 4     "citydesc": "黑龙江 双鸭山",
 5     "publishtime": "2015年09月17日10:00",
 6     "lastupdate": "2015-09-17 10:50:04",
 7     "data": [
 8         {
 9             "date": "2015-09-17",
10             "icon": "d00|n00",
11             "weather": "晴",
12             "temperature": "29°C/15°C",
13             "winddirect": "南风微风"
14         },
15         {
16             "date": "2015-09-18",
17             "icon": "d00|n00",
18             "weather": "晴",
19             "temperature": "27°C/14°C",
20             "winddirect": "南风微风"
21         },
22         {
23             "date": "2015-09-19",
24             "icon": "d03|n01",
25             "weather": "阵雨转多云",
26             "temperature": "24°C/13°C",
27             "winddirect": "东南风微风"
28         },
29         {
30             "date": "2015-09-20",
31             "icon": "d00|n00",
32             "weather": "晴",
33             "temperature": "22°C/12°C",
34             "winddirect": "东南风转西风微风"
35         },
36         {
37             "date": "2015-09-21",
38             "icon": "d00|n00",
39             "weather": "晴",
40             "temperature": "23°C/14°C",
41             "winddirect": "西风3-4级"
42         },
43         {
44             "date": "2015-09-22",
45             "icon": "d00|n01",
46             "weather": "晴转多云",
47             "temperature": "25°C/13°C",
48             "winddirect": "西南风3-4级"
49         }
50     ],
51     "live": {
52         "updatetime": null,
53         "temperature": "℃",
54         "humidity": null,
55         "winddirect": ""
56     }
57 }

JSON字符串

  1 package com.qianfeng.json3;
  2 
  3 import java.util.List;
  4 
  5 public class Weather {
  6     
  7     private String cityName;
  8     private String cityCode;
  9     private String cityDesc;
 10     private String publishtime;
 11     private String lastupdate;
 12     private List<WeatherData> datas;
 13     private Live  live;
 14     
 15     public Weather(){}
 16 
 17     public Weather(String cityName, String cityCode, String cityDesc,
 18             String publishtime, String lastupdate, List<WeatherData> datas,
 19             Live live) {
 20         super();
 21         this.cityName = cityName;
 22         this.cityCode = cityCode;
 23         this.cityDesc = cityDesc;
 24         this.publishtime = publishtime;
 25         this.lastupdate = lastupdate;
 26         this.datas = datas;
 27         this.live = live;
 28     }
 29 
 30     public String getCityName() {
 31         return cityName;
 32     }
 33 
 34     public void setCityName(String cityName) {
 35         this.cityName = cityName;
 36     }
 37 
 38     public String getCityCode() {
 39         return cityCode;
 40     }
 41 
 42     public void setCityCode(String cityCode) {
 43         this.cityCode = cityCode;
 44     }
 45 
 46     public String getCityDesc() {
 47         return cityDesc;
 48     }
 49 
 50     public void setCityDesc(String cityDesc) {
 51         this.cityDesc = cityDesc;
 52     }
 53 
 54     public String getPublishtime() {
 55         return publishtime;
 56     }
 57 
 58     public void setPublishtime(String publishtime) {
 59         this.publishtime = publishtime;
 60     }
 61 
 62     public String getLastupdate() {
 63         return lastupdate;
 64     }
 65 
 66     public void setLastupdate(String lastupdate) {
 67         this.lastupdate = lastupdate;
 68     }
 69 
 70     public List<WeatherData> getDatas() {
 71         return datas;
 72     }
 73 
 74     public void setDatas(List<WeatherData> datas) {
 75         this.datas = datas;
 76     }
 77 
 78     public Live getLive() {
 79         return live;
 80     }
 81 
 82     public void setLive(Live live) {
 83         this.live = live;
 84     }
 85 
 86     @Override
 87     public String toString() {
 88         return "Weather [cityName=" + cityName + ", cityCode=" + cityCode
 89                 + ", cityDesc=" + cityDesc + ", publishtime=" + publishtime
 90                 + ", lastupdate=" + lastupdate + ", datas=" + datas + ", live="
 91                 + live + "]";
 92     }
 93     
 94     
 95     
 96     
 97     
 98     
 99 
100 }

Weather.java

 1 package com.qianfeng.json3;
 2 
 3 public class WeatherData {
 4     
 5     private String date;
 6     private String icon;
 7     private String weather;
 8     private String temperature;
 9     private String winddirect;
10     
11     public WeatherData(){}
12 
13     public WeatherData(String date, String icon, String weather,
14             String temperature, String winddirect) {
15         super();
16         this.date = date;
17         this.icon = icon;
18         this.weather = weather;
19         this.temperature = temperature;
20         this.winddirect = winddirect;
21     }
22 
23     public String getDate() {
24         return date;
25     }
26 
27     public void setDate(String date) {
28         this.date = date;
29     }
30 
31     public String getIcon() {
32         return icon;
33     }
34 
35     public void setIcon(String icon) {
36         this.icon = icon;
37     }
38 
39     public String getWeather() {
40         return weather;
41     }
42 
43     public void setWeather(String weather) {
44         this.weather = weather;
45     }
46 
47     public String getTemperature() {
48         return temperature;
49     }
50 
51     public void setTemperature(String temperature) {
52         this.temperature = temperature;
53     }
54 
55     public String getWinddirect() {
56         return winddirect;
57     }
58 
59     public void setWinddirect(String winddirect) {
60         this.winddirect = winddirect;
61     }
62 
63     @Override
64     public String toString() {
65         return "WeatherData [date=" + date + ", icon=" + icon + ", weather="
66                 + weather + ", temperature=" + temperature + ", winddirect="
67                 + winddirect + "]";
68     }
69 }

WeatherData.java

 1 package com.qianfeng.json3;
 2 
 3 public class Live {
 4     
 5     private String updatetime;
 6     private String temperature;
 7     private String humidity;
 8     private String winddirect;
 9     
10     public Live(){}
11 
12     public Live(String updatetime, String temperature, String humidity,
13             String winddirect) {
14         super();
15         this.updatetime = updatetime;
16         this.temperature = temperature;
17         this.humidity = humidity;
18         this.winddirect = winddirect;
19     }
20 
21     public String getUpdatetime() {
22         return updatetime;
23     }
24 
25     public void setUpdatetime(String updatetime) {
26         this.updatetime = updatetime;
27     }
28 
29     public String getTemperature() {
30         return temperature;
31     }
32 
33     public void setTemperature(String temperature) {
34         this.temperature = temperature;
35     }
36 
37     public String getHumidity() {
38         return humidity;
39     }
40 
41     public void setHumidity(String humidity) {
42         this.humidity = humidity;
43     }
44 
45     public String getWinddirect() {
46         return winddirect;
47     }
48 
49     public void setWinddirect(String winddirect) {
50         this.winddirect = winddirect;
51     }
52 
53     @Override
54     public String toString() {
55         return "Live [updatetime=" + updatetime + ", temperature="
56                 + temperature + ", humidity=" + humidity + ", winddirect="
57                 + winddirect + "]";
58     }
59     
60     
61 
62 }

Live.java

 1 package com.qianfeng.json3;
 2 
 3 import java.util.ArrayList;
 4 import java.util.List;
 5 
 6 import org.json.JSONArray;
 7 import org.json.JSONException;
 8 import org.json.JSONObject;
 9 
10 public class ParseTool {
11     
12     public static Weather parserWeather(String jsonString) throws JSONException
13     {
14         Weather weather = new Weather();
15         
16         JSONObject object = new JSONObject(jsonString);
17         String cityname = object.getString("cityname");
18         String citycode = object.getString("citycode");
19         String citydesc = object.getString("citydesc");
20         String publishtime = object.getString("publishtime");
21         String lastupdate = object.getString("lastupdate");
22         
23         weather.setCityName(cityname);
24         weather.setCityCode(citycode);
25         weather.setCityDesc(citydesc);
26         weather.setPublishtime(publishtime);
27         weather.setLastupdate(lastupdate);
28         
29         JSONArray array = object.getJSONArray("data");
30         WeatherData data = null;
31         List<WeatherData>  datas = new ArrayList<WeatherData>();
32         for(int i=0;i<array.length();i++)
33         {
34             JSONObject obj = array.getJSONObject(i);
35             String date = obj.getString("date");
36             String icon = obj.getString("icon");
37             String weathers = obj.getString("weather");
38             String temperature = obj.getString("temperature");
39             String winddirect = obj.getString("winddirect");
40             data = new WeatherData();
41             data.setDate(date);
42             data.setIcon(icon);
43             data.setWeather(weathers);
44             data.setTemperature(temperature);
45             data.setWinddirect(winddirect);
46             datas.add(data);
47         }
48         
49         weather.setDatas(datas);
50         
51         JSONObject jsonObj = object.getJSONObject("live");
52         String updatetime = jsonObj.getString("updatetime");
53         String temperatures = jsonObj.getString("temperature");
54         String humidity = jsonObj.getString("humidity");
55         String winddirects = jsonObj.getString("winddirect");
56         Live live = new Live();
57         live.setUpdatetime(updatetime);
58         live.setTemperature(temperatures);
59         live.setHumidity(humidity);
60         live.setWinddirect(winddirects);
61         
62         weather.setLive(live);
63         
64         return weather;
65     }
66 
67 }

ParseTool .java

 1 package com.qianfeng.json3;
 2 
 3 import java.io.ByteArrayOutputStream;
 4 import java.io.IOException;
 5 import java.io.InputStream;
 6 import java.net.HttpURLConnection;
 7 import java.net.MalformedURLException;
 8 import java.net.URL;
 9 import java.util.ArrayList;
10 import java.util.List;
11 
12 import org.json.JSONArray;
13 import org.json.JSONException;
14 import org.json.JSONObject;
15 
16 public class HttpUtil {
17     
18     // 获取服务器端json字符串
19     public static String getJsonStr(String path) throws IOException
20     {
21         URL url = new URL(path);
22         HttpURLConnection conn = (HttpURLConnection) url.openConnection();
23         
24         conn.setRequestMethod("GET");
25         conn.setConnectTimeout(5000);
26         conn.setDoInput(true);
27         
28         conn.connect();
29         
30         InputStream in = null;
31         if(conn.getResponseCode()==200)
32         {
33             in = conn.getInputStream();
34         }
35         return changeToStr(in);
36     }
37 
38     private static String changeToStr(InputStream in) throws IOException {
39         ByteArrayOutputStream bos = new ByteArrayOutputStream();
40         byte[] arr = new byte[1024];
41         int len = 0;
42         while((len = in.read(arr))!=-1)
43         {
44             bos.write(arr,0,len);
45         }
46         return new String(bos.toByteArray(),"utf-8");
47     }
48     
49     
50 
51 }

HttpUtil.java

 1 package com.qianfeng.json3;
 2 
 3 import java.io.IOException;
 4 
 5 import org.json.JSONException;
 6 
 7 public class Test {
 8 
 9     /**
10      * @param args
11      * @throws IOException 
12      * @throws JSONException 
13      */
14     public static void main(String[] args) throws IOException, JSONException {
15         
16         String path = "http://weather.xcyh.org/101051301/json/6";
17         
18         String jsonString = HttpUtil.getJsonStr(path);
19         
20         Weather weather = ParseTool.parserWeather(jsonString);
21         
22         System.out.println(weather);
23 
24     }
25 }

Test.java

　　未完，待续。

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原文地址：https://www.cnblogs.com/enjoy-coding/p/4815705.html