如何使用百度天气预报API接口

前些天知道了如何获取数字签名SHA1，那它用来干嘛的呢？今天就来学习一下它的用处。
比如说我们要开发一款基于位置的服务，如地图、天气预报等。我们要用到API Key。

百度API Key申请地址：http://lbsyun.baidu.com/apiconsole/key

创建应用 如图：

提交后得到API Key 如图：

接口实例：http://api.map.baidu.com/telematics/v3/weather？location=南昌&output=json&ak=你的API Key&mcode=你的数字签名SHA1;com.example.administrator.jsontest（包名）

接口参数说明

参数类型	参数名称	是否必须	具体描述
String	location	true	输入城市名或经纬度，城市名如北京或者131，经纬度格式为lng，lat坐标，如：location=116.305145,39.982368;全国值为all，返回省会城市自治区，港澳台天气情况多城市天气预报中间用“|”分隔，如：location=116.305145,39.982368|123.342323,36238945|...
String	output	false	输出的数据格式，默认为xml格式，当output设置为json时，输出的为json数据格式
String	coord_type	false	请求参数坐标类型，默认为gcj02经纬度坐标。允许的值为bd09ll、bd09mc、gcj02、wgs84；

返回的JSON数据

{
    "error":0,
    "status":"success",
    "date":"2016-03-05",
    "results":[
        {
            "currentCity":"北京", 
            "pm25":"144", 
            "index":[ 
                { 
                    "title":"穿衣",
                    "zs":"较冷", 
                    "tipt":"穿衣指数",
                    "des":"建议着厚外套加毛衣等服装。年老体弱者宜着大衣、呢外套加羊毛衫。"},
                {
                    "title":"洗车", 
                    "zs":"不宜", 
                    "tipt":"洗车指数",
                    "des":"不宜洗车，未来24小时内有扬沙或浮尘，如果在此期间洗车，极易很快蒙上新的灰尘。"},
                {
                    "title":"旅游",
                    "zs":"一般", 
                    "tipt":"旅游指数",
                    "des":"风稍大，扬沙或浮尘天气对能见度和空气质量都会有些影响，出行请注意交通安全和采取适当的防尘措施。"},
                {
                    "title":"感冒",
                    "zs":"易发", 
                    "tipt":"感冒指数",
                    "des":"昼夜温差大，风力较强，易发生感冒，请注意适当增减衣服，加强自我防护避免感冒。"},
                {
                    "title":"运动",
                    "zs":"较不宜",
                    "tipt":"运动指数",
                    "des":"有扬沙或浮尘，建议适当停止户外运动，选择在室内进行运动，以避免吸入更多沙尘，有损健康。"},
                {
                    "title":"紫外线强度",
                    "zs":"最弱", 
                    "tipt":"紫外线强度指数",
                    "des":"属弱紫外线辐射天气，无需特别防护。若长期在户外，建议涂擦SPF在8-12之间的防晒护肤品。"}
           ],
  "weather_data":[
              {
                  "date":"周六 03月05日 (实时：12℃)",              "dayPictureUrl":"http://api.map.baidu.com/images/weather/day/fuchen.png",
    "nightPictureUrl":"http://api.map.baidu.com/images/weather/night/qing.png",
                  "weather":"浮尘转晴",
                  "wind":"北风4-5级", 
                  "temperature":"12 ~ -1℃"},
  {
                  "date":"周日",
 "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":"微风", 
                  "temperature":"10 ~ -3℃"},
  { 
                  "date":"周一",            "dayPictureUrl":"http://api.map.baidu.com/images/weather/day/duoyun.png",
 "nightPictureUrl":"http://api.map.baidu.com/images/weather/night/yin.png",
                  "weather":"多云转阴",
                  "wind":"微风", 
                  "temperature":"13 ~ 2℃"},
  { 
                  "date":"周二",                "dayPictureUrl":"http://api.map.baidu.com/images/weather/day/yin.png",
 "nightPictureUrl":"http://api.map.baidu.com/images/weather/night/duoyun.png",
              "weather":"阴转多云",
              "wind":"北风3-4级", 
              "temperature":"6 ~ -1℃"}
  ]}]}

我们来写个demo，代码如下：

package com.example.administrator.jsontest;

public class MainActivity extends Activity {
    private Button button;
    private TextView textView;
    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case 0:
                    String re = (String) msg.obj;
                    textView.setText(re);
                    break;
            }
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button = (Button) findViewById(R.id.button);
        textView = (TextView) findViewById(R.id.textView);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.i("TAG", "点击了Button");
                sendRequestWithHttpClient();
            }
        });
    }

    private void sendRequestWithHttpClient() {
        new Thread(new Runnable() {
            @Override
            public void run() {
                HttpURLConnection connection = null;
                try {
                    URL url = new URL("http://api.map.baidu.com/telematics/v3/weather?location=南昌&output=json&ak=8ixCCFzlBB617YX7tONI2P5B&mcode=1C:6B:42:33:E8:A6:DC:A2:11:6E:26:EC:84:BD:42:E3:8E:6B:57:9A;com.example.administrator.jsontest");
                    connection = (HttpURLConnection) url.openConnection();
                    connection.setRequestMethod("GET");
                    connection.setConnectTimeout(5000);
                    connection.setReadTimeout(5000);
                    InputStream in = connection.getInputStream();
                    BufferedReader reader = new BufferedReader(new InputStreamReader(in));
                    StringBuilder response = new StringBuilder();
                    String line;
                    while ((line = reader.readLine()) != null) {
                        response.append(line);
                    }
                    Log.i("TAG", response.toString());                    parseJSONObjectOrJSONArray(response.toString());
                } catch (MalformedURLException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }).start();
    }

    //解析JSON数据
    private void parseJSONObjectOrJSONArray(String jsonData) {
        try {
            String count = "";
            JSONObject jsonObject = new JSONObject(jsonData);
            JSONArray jsonArray = jsonObject.getJSONArray("results");
            if (jsonArray.length() > 0) {
                JSONObject object = jsonArray.getJSONObject(0);
                String city = object.optString("currentCity");
                JSONArray array = object.getJSONArray("weather_data");
                for (int i = 0; i < array.length(); i++) {
                    JSONObject jsonObject1 = array.getJSONObject(i);
                    String dateDay = jsonObject1.optString("date");
                    String weather = jsonObject1.optString("weather");
                    String wind = jsonObject1.optString("wind");
                    String temperature = jsonObject1.optString("temperature");
                    count =count +"\n"+ dateDay + " " + weather + " " + wind + " " + temperature;
                    Log.i("AAA",count);
                }

                Message message = new Message();
                message.what = 0;
                message.obj = count;
                handler.sendMessage(message);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

运行结果如下：