獲取json數據中某一特定鍵值
我們介紹了如何將真箇json數據賦值給一個成員個數相同的類中,但是有時我們並不需要json的所有數據,那麼如何獲得json中某一特定值呢。首先假如我們要獲得如下json數據的「weather」值
{"weatherinfo":{"city":"北京","cityid":"101010100","temp1":"10℃","temp2":"-2℃","weather":"晴","img1":"d0.gif","img2":"n0.gif","ptime":"08:00"}}
首先定義全局變數:JSONObject jsonObject = new JSONObject();
方法封裝如下:
//解析單個Json值,用於獲取天氣狀況
public void readJsonGetWeather(String URL) {
StringBuilder stringBuilder = new StringBuilder();
HttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(URL);
try {
HttpResponse response = client.execute(httpGet);
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200) {
HttpEntity entity = response.getEntity();
InputStream content = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(content));
String line;
while ((line = reader.readLine()) != null) {
stringBuilder.append(line);
}
} else {
Log.e("JSON", "Failed to download file");
}
jsonObject = new JSONObject(stringBuilder.toString()).getJSONObject("weatherinfo");
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
調用該方法:
String url_weather="http://youraddress.cn/data/cityinfo/101010100.html";
readJsonGetWeather(url_weather);
使用值:
climate = jsonObject.getString("weather");//使用哪一個鍵值就輸入對應的鍵值名稱
climateTv.setText(climate);
另一種方法是利用上一文中的方法,先獲得json數據,然後獲得jsonObject,主要代碼如下:
調用:
String url_weather = "http://youraddress.cn/data/cityinfo/101010100.html";
String onlyWeatherResult = connServerForResult(url_weather);//調用上文中的connServerForResult函數,獲得json數據。
//具體函數參見上一篇博文
readJsonGetWeather(onlyWeatherResult);
其中readJsonGetWeather函數可精簡為:
// 解析單個Json值,用於獲取天氣狀況
public void readJsonGetWeather(String jsonString) {
try {
jsonObject = new JSONObject(jsonString.toString()).getJSONObject("weatherinfo");
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
引用的方法是一樣的:climate = jsonObject.getString("weather");
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TAG:程序員小新人學習 |