CODEWITHSUNDEEP
androidjson
Dim
Dim

Reputation: 4807

Reading online JSON android

I have online JSON file that looks like this:

{  
    "iPadVersion": "1.0",
    "AndroidVersion": "1.0"
}

I am trying to read it like this, (this part of code is in AsyncTask):

JSONParser jParser = new JSONParser();
JSONObject json = jParser.getJSONFromUrl("http://mylink/db.json");
String str = "tmp";

            try {
                  str = json.getString("AndroidVersion");
            } catch (JSONException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }


            Log.d(TAG, ""+str);

I get always "tmp" at log.d, it does not work.

StactTrace:

    05-16 12:54:08.605: W/System.err(20406): java.io.FileNotFoundException: /http:/mylink/db.json: open failed: ENOENT (No such file or directory)
    05-16 12:54:08.605: W/System.err(20406):    at libcore.io.IoBridge.open(IoBridge.java:406)
    05-16 12:54:08.605: W/System.err(20406):    at java.io.FileInputStream.<init>(FileInputStream.java:78)
    05-16 12:54:08.605: W/System.err(20406):    at java.io.FileInputStream.<init>(FileInputStream.java:105)
    05-16 12:54:08.605: W/System.err(20406):    at java.io.FileReader.<init>(FileReader.java:66)
    05-16 12:54:08.605: W/System.err(20406):    at com.weterworks.JSONParser.getJSONFromUrl(JSONParser.java:37)
    05-16 12:54:08.605: W/System.err(20406):    at com.weterworks.MainActivity$sync.<init>(MainActivity.java:359)
    05-16 12:54:08.605: W/System.err(20406):    at com.weterworks.MainActivity.onCreate(MainActivity.java:263)
    05-16 12:54:08.605: W/System.err(20406):    at android.app.Activity.performCreate(Activity.java:4465)
    05-16 12:54:08.605: W/System.err(20406):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
    05-16 12:54:08.605: W/System.err(20406):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
    05-16 12:54:08.605: W/System.err(20406):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
    05-16 12:54:08.605: W/System.err(20406):    at android.app.ActivityThread.access$600(ActivityThread.java:123)
    05-16 12:54:08.605: W/System.err(20406):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
    05-16 12:54:08.605: W/System.err(20406):    at android.os.Handler.dispatchMessage(Handler.java:99)
    05-16 12:54:08.605: W/System.err(20406):    at android.os.Looper.loop(Looper.java:137)
    05-16 12:54:08.605: W/System.err(20406):    at android.app.ActivityThread.main(ActivityThread.java:4424)
    05-16 12:54:08.605: W/System.err(20406):    at java.lang.reflect.Method.invokeNative(Native Method)
    05-16 12:54:08.615: W/System.err(20406):    at java.lang.reflect.Method.invoke(Method.java:511)
    05-16 12:54:08.615: W/System.err(20406):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
    05-16 12:54:08.615: W/System.err(20406):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
    05-16 12:54:08.615: W/System.err(20406):    at dalvik.system.NativeStart.main(Native Method)
    05-16 12:54:08.615: W/System.err(20406): Caused by: libcore.io.ErrnoException: open failed: ENOENT (No such file or directory)
    05-16 12:54:08.615: W/System.err(20406):    at libcore.io.Posix.open(Native Method)
    05-16 12:54:08.615: W/System.err(20406):    at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
    05-16 12:54:08.615: W/System.err(20406):    at libcore.io.IoBridge.open(IoBridge.java:390)
    05-16 12:54:08.615: W/System.err(20406):    ... 20 more
    05-16 12:54:08.615: W/System.err(20406): org.json.JSONException: No value for AndroidVersion
    05-16 12:54:08.615: W/System.err(20406):    at org.json.JSONObject.get(JSONObject.java:354)
    05-16 12:54:08.615: W/System.err(20406):    at org.json.JSONObject.getString(JSONObject.java:510)
    05-16 12:54:08.615: W/System.err(20406):    at com.weterworks.MainActivity$sync.doInBackground(MainActivity.java:404)
    05-16 12:54:08.615: W/System.err(20406):    at com.weterworks.MainActivity$sync.doInBackground(MainActivity.java:1)
    05-16 12:54:08.615: W/System.err(20406):    at android.os.AsyncTask$2.call(AsyncTask.java:264)
    05-16 12:54:08.615: W/System.err(20406):    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
    05-16 12:54:08.625: W/System.err(20406):    at java.util.concurrent.FutureTask.run(FutureTask.java:137)
    05-16 12:54:08.625: W/System.err(20406):    at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:208)
    05-16 12:54:08.625: W/System.err(20406):    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
    05-16 12:54:08.625: W/System.err(20406):    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
    05-16 12:54:08.625: W/System.err(20406):    at java.lang.Thread.run(Thread.java:856)

JsonParser Class:

public class JSONParser {

static InputStream is = null;
static JSONObject jObj = null;
static String json = "";

// constructor
public JSONParser() {

}

public JSONObject getJSONFromUrl(String url) {


    try {
        BufferedReader reader = new BufferedReader(new FileReader(url));
        String line, results = "";
        while ((line = reader.readLine()) != null) {
            results += line;
        }
        reader.close();

        jObj = new JSONObject(results);
    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (JSONException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return jObj;

     }
}

Upvotes: 0

Views: 1932

Answers (2)

Perception
Perception

Reputation: 80603

You are trying to read data from a URL, but you are using a FileReader in your stream chain. This simply won't work, as a FileReader interprets its string argument as a file on your local system (see Javadoc).

What you need to do is use a HTTP library to download the data from the given URL, then parse it into a JSON object. I show an example below, using the built in HTTP classes in the SDK:

public class JSONParser {
    private static final String USER_AGENT = "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_5) AppleWebKit/537.31 (KHTML, like Gecko) Chrome/26.0.1410.65 Safari/537.31";

    public JSONObject getJSONFromUrl(String url) {

        try {
            final HttpURLConnection connection = (HttpURLConnection) new URL(
                    url).openConnection();
            connection.setRequestProperty("User-Agent", USER_AGENT);

            if (connection.getResponseCode() == 200) {
                final BufferedReader reader = new BufferedReader(
                        new InputStreamReader(connection.getInputStream()));

                String line = null;
                final StringBuffer buffer = new StringBuffer(4096);
                while ((line = reader.readLine()) != null) {
                    buffer.append(line);
                }
                reader.close();

                final JSONObject jObj = new JSONObject(buffer.toString());
                return jObj;
            } else {
                return null;
            }

        } catch (IOException e) {
            throw new RuntimeException(e);
        } catch (JSONException e) {
            throw new RuntimeException(e);
        }
    }
}

Side note: Instead of creating your own parsing utility for this, you could include Jackson in your project, and use this one-liner:

final JsonNode jsonObj = new ObjectMapper().readTree(new URL(
        "http://www.example.com/json"));

Upvotes: 3

Jithu
Jithu

Reputation: 1478

Check your server link and use it properly. I think, You have the problem with the server URL. log your url string and try to get it through browser.

Upvotes: 0

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