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Android 解析JSON

　　上次讲了XML格式数据的解析方式，这次要说的是如何解析JSON数据格式，相对与XML，JSON解析数据的方式在于它的体积更小，在网络上传输可以更省流量。

　　这次在网上找到一个中国天气json数据的API接口，这就更便于我们直接去解析别人弄好的数据拿来使用，下面这是从网上下载json文件，当然也可以自己简单的编辑：

{"desc":"OK","status":1000,"data":{"wendu":"25","ganmao":"相对于今天将会出现大幅度降温，风力较大，易发生感冒，请注意适当增加衣服。","forecast":[{"fengxiang":"无持续风向","fengli":"微风级","high":"高温 26℃","type":"多云","low":"低温 17℃","date":"2日星期二"},{"fengxiang":"无持续风向","fengli":"5-6级","high":"高温 22℃","type":"大雨","low":"低温 17℃","date":"3日星期三"},{"fengxiang":"无持续风向","fengli":"微风级","high":"高温 25℃","type":"晴","low":"低温 15℃","date":"4日星期四"},{"fengxiang":"无持续风向","fengli":"微风级","high":"高温 27℃","type":"晴","low":"低温 16℃","date":"5日星期五"},{"fengxiang":"无持续风向","fengli":"微风级","high":"高温 23℃","type":"阴","low":"低温 16℃","date":"6日星期六"}],"yesterday":{"fl":"微风","fx":"东风","high":"高温 23℃","type":"中雨","low":"低温 15℃","date":"1日星期一"},"aqi":"79","city":"武汉"}}

  1 package com.example.weather;
  2 
  3 import java.io.BufferedReader;
  4 import java.io.InputStream;
  5 import java.io.InputStreamReader;
  6 import java.net.HttpURLConnection;
  7 import java.net.URL;
  8 import java.net.URLEncoder;
  9 
 10 import org.json.JSONArray;
 11 import org.json.JSONException;
 12 import org.json.JSONObject;
 13 
 14 import android.app.Activity;
 15 import android.content.pm.ApplicationInfo;
 16 import android.content.pm.PackageInfo;
 17 import android.os.Bundle;
 18 import android.os.Handler;
 19 import android.os.Message;
 20 import android.text.TextUtils;
 21 import android.view.View;
 22 import android.widget.EditText;
 23 import android.widget.TextView;
 24 import android.widget.Toast;
 25 
 26 import com.example.weather.util.ReadStrean;
 27 
 28 public class MainActivity extends Activity {
 29     protected static final int SUCCESS = 0;
 30     protected static final int ERROR =1;
 31     protected static final int FAILL = 2;
 32     private EditText et_city;
 33     private TextView tv_one,tv_two,tv_three;
 34     private String version;
 35     private Handler handler=new Handler(){
 36         public void handleMessage(android.os.Message msg) {
 37             switch (msg.what) {
 38             case SUCCESS:
 39                 JSONArray array = (JSONArray)msg.obj;
 40                 try {
 41                     tv_one.setText(array.getString(0).toString());
 42                     tv_two.setText(array.getString(1).toString());
 43                     tv_three.setText(array.getString(2).toString());
 44                 } catch (JSONException e) {
 45                     e.printStackTrace();
 46                 }
 47                 break;
 48 
 49             case ERROR:
 50                 Toast.makeText(MainActivity.this,"请输入正确的城市名称" , 0).show();
 51                 break;
 52             case FAILL:
 53                 Toast.makeText(MainActivity.this,"网络是否连接！" , 0).show();
 54                 break;
 55             }
 56         };
 57     };
 58 
 59     @Override
 60     protected void onCreate(Bundle savedInstanceState) {
 61         super.onCreate(savedInstanceState);
 62         setContentView(R.layout.activity_main);
 63         initView();
 64 //        initDate();
 65     }
 66 
 67 //    private void initDate() {
 68 //        try {
 69 //            PackageInfo info = getApplicationContext().getPackageManager().getPackageInfo(getApplicationContext().getPackageName(), 0);
 70 //            version= info.versionName;
 71 //            
 72 //            new Thread(){
 73 //                public void run() {
 74 //                    try {
 75 //                        URL url=new URL("http://192.168.1.113:8080/version.json");
 76 //                        //打开网络连接
 77 //                        HttpURLConnection conn= (HttpURLConnection) url.openConnection();
 78 //                        //设置连接方式"GET"
 79 //                        conn.setRequestMethod("GET");
 80 //                        //设置http网络连接时间
 81 //                        conn.setConnectTimeout(5000);
 82 //                        //请求服务器得到一个返回码
 83 //                        int code= conn.getResponseCode();
 84 //                        if(code == 200){
 85 //                            //getInputStream方法得到输入流其实就是从服务器端发回的数据
 86 //                            InputStream is=conn.getInputStream();
 87 //                            StringBuilder builder=new StringBuilder();
 88 //                            int len;
 89 //                            String line;
 90 //                            BufferedReader read=new BufferedReader(new InputStreamReader(is));
 91 //                            while ((line = read.readLine())!=null) {
 92 //                                builder.append(line);
 93 //                            }
 94 //                            is.close();
 95 //                            read.close();
 96 //                            String json = builder.toString();
 97 //                            System.out.println(json+"123456");
 98 //                            JSONObject object=new JSONObject(json);
 99 //                            String appversion = object.getString("version");
100 //                            if(version.equals(appversion)){
101 //                                runOnUiThread(new  Runnable() {
102 //                                    public void run() {
103 //                                        Toast.makeText(MainActivity.this, "暂无新版本", 0).show();
104 //                                    }
105 //                                });
106 //                            }else {
107 //                                
108 //                            }
109 //                        }
110 //                        else {
111 //                            System.out.println("nononono");
112 //                        }
113 //                    } catch (Exception e) {
114 //                        // TODO Auto-generated catch block
115 //                        e.printStackTrace();
116 //                    }
117 //                };
118 //            }.start();
119 //        } catch (Exception e) {
120 //            // TODO Auto-generated catch block
121 //            e.printStackTrace();
122 //        }
123 //    }
124 
125     private void initView() {
126         et_city=(EditText) findViewById(R.id.et_city);
127         tv_one=(TextView) findViewById(R.id.tv_one);
128         tv_two=(TextView) findViewById(R.id.tv_two);
129         tv_three=(TextView) findViewById(R.id.tv_three);
130     }
131     public void onclick (View v){
132         final String city = et_city.getText().toString().trim();
133         if(TextUtils.isEmpty(city)){
134             Toast.makeText(this, "请输入城市名称", 0).show();
135             return;
136         }
137         new Thread(){
138             public void run() {
139                 try {
140                     String path="http://wthrcdn.etouch.cn/weather_mini?city="+URLEncoder.encode(city, "utf-8");
141                     URL url = new URL(path);
142                     //打开网络连接
143                     HttpURLConnection conn = (HttpURLConnection)url.openConnection();
144                     //设置连接方式"GET"
145                     conn.setRequestMethod("GET");
146                     //设置http网络连接时间
147                     conn.setConnectTimeout(5000);
148                     //请求服务器得到一个返回码
149                     int code = conn.getResponseCode();
150                     if(code== 200){
151                         //getInputStream方法得到输入流其实就是从服务器端发回的数据
152                         InputStream is= conn.getInputStream();
153                         String json = ReadStrean.readstreanUtil(is);
154                         is.close();
155                         //创建一个JSONObject对象
156                         JSONObject object= new JSONObject(json);
157                         //取得json数据格式的第一个键，也是解析json数据的入口
158                         String desc = object.getString("desc");
159                         if("OK".equals(desc)){
160                             //开始解析json
161                             JSONObject data = object.getJSONObject("data");
162                             JSONArray array= data.getJSONArray("forecast");
163                             Message msg=new Message();
164                             msg.what=SUCCESS;
165                             msg.obj=array;
166                             handler.sendMessage(msg);
167                         }
168                     }else {
169                         Message msg=new Message();
170                         msg.what=FAILL;
171                         handler.sendMessage(msg);
172                     }
173 
174                 } catch (Exception e) {
175                     e.printStackTrace();
176                     Message msg=new Message();
177                     msg.what=ERROR;
178                     handler.sendMessage(msg);
179                 }
180             };
181 
182         }.start();
183 
184     }
185 }

自定义读取流的工具类：

package com.example.weather.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

public class ReadStrean {
    public static String readstreanUtil(InputStream is) throws IOException{
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        int len;
        byte [] arr=new byte[1024];
        while((len=is.read(arr))!=-1){
            bos.write(arr, 0, len);
        }
        is.close();
        bos.close();
        return bos.toString("utf-8");
        
    }
}

xml布局：

 1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 2     xmlns:tools="http://schemas.android.com/tools"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:orientation="vertical"
 6     tools:context="${relativePackage}.${activityClass}" >
 7 
 8     <EditText
 9         android:id="@+id/et_city"
10         android:layout_width="match_parent"
11         android:layout_height="wrap_content"
12         android:hint="请输入城市名称：" />
13 
14     <Button
15         android:id="@+id/btn_see"
16         android:onClick="onclick"
17         android:layout_width="match_parent"
18         android:layout_height="wrap_content"
19         android:text="查      看" />
20 
21     <TextView
22         android:id="@+id/tv_one"
23         android:layout_width="match_parent"
24         android:layout_height="0dip"
25         android:layout_weight="1"
26         android:text="今天"
27         android:textColor="#FF1493" />
28 
29     <TextView
30         android:layout_width="match_parent"
31         android:layout_height="1dp"
32         android:background="@android:color/darker_gray" />
33 
34     <TextView
35         android:id="@+id/tv_two"
36         android:layout_width="match_parent"
37         android:layout_height="0dip"
38         android:layout_weight="1"
39         android:text="明天"
40         android:textColor="#DC143C" />
41 
42     <TextView
43         android:layout_width="match_parent"
44         android:layout_height="1dp"
45         android:background="@android:color/darker_gray" />
46 
47     <TextView
48         android:id="@+id/tv_three"
49         android:layout_width="match_parent"
50         android:layout_height="0dip"
51         android:layout_weight="1"
52         android:text="后天"
53         android:textColor="#BC8F8F" />
54 
55 </LinearLayout>

View Code

最终解析显示图：

添加访问网络权限：<uses-permission android:name="android.permission.INTERNET"/>

源码下载地址：http://pan.baidu.com/s/1qXVGyZU

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原文地址：https://www.cnblogs.com/boket/p/6802121.html