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:
1.
2.
3.
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.
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);
2.
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);
3.
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 }
4.
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 }
5.
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 }
6.
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。
时间： 2024-10-08 07:54:38