从URLparsingJSON

有没有最简单的方法来parsing来自URL的JSON？ 我用Gson我找不到任何有用的例子。

Answer 1

1. 首先你需要下载URL（文本）：

   private static String readUrl(String urlString) throws Exception { BufferedReader reader = null; try { URL url = new URL(urlString); reader = new BufferedReader(new InputStreamReader(url.openStream())); StringBuffer buffer = new StringBuffer(); int read; char[] chars = new char[1024]; while ((read = reader.read(chars)) != -1) buffer.append(chars, 0, read); return buffer.toString(); } finally { if (reader != null) reader.close(); } } 

2. 那么你需要parsing它（在这里你有一些select）。

   • GSON（完整示例）：

      static class Item { String title; String link; String description; } static class Page { String title; String link; String description; String language; List<Item> items; } public static void main(String[] args) throws Exception { String json = readUrl("http://www.javascriptkit.com/" + "dhtmltutors/javascriptkit.json"); Gson gson = new Gson(); Page page = gson.fromJson(json, Page.class); System.out.println(page.title); for (Item item : page.items) System.out.println(" " + item.title); } 

     输出：

      javascriptkit.com Document Text Resizer JavaScript Reference- Keyboard/ Mouse Buttons Events Dynamically loading an external JavaScript or CSS file 

   • 试试json.org的java API：

      try { JSONObject json = new JSONObject(readUrl("...")); String title = (String) json.get("title"); ... } catch (JSONException e) { e.printStackTrace(); } 

Answer 2

您可以使用org.apache.commons.io.IOUtils进行下载，使用org.json.JSONTokener进行分析：

 JSONObject jo = (JSONObject) new JSONTokener(IOUtils.toString(new URL("http://gdata.youtube.com/feeds/api/videos/SIFL9qfmu5U?alt=json"))).nextValue(); System.out.println(jo.getString("version")); 

Answer 3

GSON有一个构build器，它需要一个Reader对象： fromJson（Reader json，Class classOfT） 。

这意味着你可以从一个URL创build一个Reader，然后把它传递给Gson来消费这个stream并进行反序列化。

只有三行相关的代码。

 import java.io.InputStreamReader; import java.net.URL; import java.util.Map; import com.google.gson.Gson; public class GsonFetchNetworkJson { public static void main(String[] ignored) throws Exception { URL url = new URL("https://httpbin.org/get?color=red&shape=oval"); InputStreamReader reader = new InputStreamReader(url.openStream()); MyDto dto = new Gson().fromJson(reader, MyDto.class); // using the deserialized object System.out.println(dto.headers); System.out.println(dto.args); System.out.println(dto.origin); System.out.println(dto.url); } private class MyDto { Map<String, String> headers; Map<String, String> args; String origin; String url; } } 

Answer 4

这是一个简单的方法。

首先从urlparsingJSON –

 public String readJSONFeed(String URL) { StringBuilder stringBuilder = new StringBuilder(); HttpClient httpClient = new DefaultHttpClient(); HttpGet httpGet = new HttpGet(URL); try { HttpResponse response = httpClient.execute(httpGet); StatusLine statusLine = response.getStatusLine(); int statusCode = statusLine.getStatusCode(); if (statusCode == 200) { HttpEntity entity = response.getEntity(); InputStream inputStream = entity.getContent(); BufferedReader reader = new BufferedReader( new InputStreamReader(inputStream)); String line; while ((line = reader.readLine()) != null) { stringBuilder.append(line); } inputStream.close(); } else { Log.d("JSON", "Failed to download file"); } } catch (Exception e) { Log.d("readJSONFeed", e.getLocalizedMessage()); } return stringBuilder.toString(); } 

然后放置一个任务，然后从JSON中读取所需的值 –

 private class ReadPlacesFeedTask extends AsyncTask<String, Void, String> { protected String doInBackground(String... urls) { return readJSONFeed(urls[0]); } protected void onPostExecute(String result) { JSONObject json; try { json = new JSONObject(result); ////CREATE A JSON OBJECT//// JSONObject data = json.getJSONObject("JSON OBJECT NAME"); ////GET A STRING//// String title = data.getString(""); //Similarly you can get other types of data //Replace String to the desired data type like int or boolean etc. } catch (JSONException e1) { e1.printStackTrace(); } //GETTINGS DATA FROM JSON ARRAY// try { JSONObject jsonObject = new JSONObject(result); JSONArray postalCodesItems = new JSONArray( jsonObject.getString("postalCodes")); JSONObject postalCodesItem = postalCodesItems .getJSONObject(1); } catch (Exception e) { Log.d("ReadPlacesFeedTask", e.getLocalizedMessage()); } } } 

然后你可以放置这样的任务 –

 new ReadPlacesFeedTask() .execute("JSON URL"); 

Answer 5

  import org.apache.commons.httpclient.util.URIUtil; import org.apache.commons.io.FileUtils; import groovy.json.JsonSlurper; import java.io.File; tmpDir = "/defineYourTmpDir" URL url = new URL("http://yourOwnURL.com/file.json"); String path = tmpDir + "/tmpRemoteJson" + ".json"; remoteJsonFile = new File(path); remoteJsonFile.deleteOnExit(); FileUtils.copyURLToFile(url, remoteJsonFile); String fileTMPPath = remoteJsonFile.getPath(); def inputTMPFile = new File(fileTMPPath); remoteParsedJson = new JsonSlurper().parseText(inputTMPFile.text); 

Answer 6

 public static TargetClassJson downloadPaletteJson(String url) throws IOException { if (StringUtils.isBlank(url)) { return null; } String genreJson = IOUtils.toString(new URL(url).openStream()); return new Gson().fromJson(genreJson, TargetClassJson.class); } 

Answer 7

我用java 1.8和com.fasterxml.jackson.databind.ObjectMapper

 ObjectMapper mapper = new ObjectMapper(); Integer value = mapper.readValue(new URL("your url here"), Integer.class); 

Integer.class也可以是一个复杂的types。 只是例如使用。

Answer 8

一个简单的替代scheme：

• 将URL粘贴到json到csv转换器中

• 在Excel或Open Office中打开CSV文件

• 使用电子表格工具parsing数据