我想从此 json url 检索数据，但给出了错误。我放了最后一个我有另一个json，这个代码可以完美地工作，但是在这里不起作用，那么问题是什么以及如何解决？
JsonParserSearch.java
public class JsonParserSearch
{
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JsonParserSearch() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser finaal", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
SearchListActivity.java
公共类 SearchlistActivity 扩展 Activity {
private static String url="http://ajax.googleapis.com/ajax/services/search/local?v=1.0&q=restaurant&rsz=8&sll=-27.5595451,-48.6206452&radius=1000&output=json";
private static final String TAG_RESULTS = "results";
private static final String TAG_RESPONSEDATA="responseData";
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//JSONArray results = null;
JSONArray responseData=null;
// Hashmap for ListView
ArrayList<HashMap<String, String>> contactList = new ArrayList<HashMap<String, String>>();
// Creating JSON Parser instance
JsonParserSearch jParser = new JsonParserSearch();
// getting JSON string from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting Array of Contacts
responseData = json.getJSONArray(TAG_RESPONSEDATA);
Log.e("jsonnn data","sfsssss00000-------->"+responseData);
}
catch (JSONException e) {
e.printStackTrace();
}
}
}
11-09 01:18:14.241: E/Buffer Error(275): Error converting result java.lang.NullPointerException
11-09 01:18:14.241: E/JSON Parser finaal(275): Error parsing data org.json.JSONException: End of input at character 0 of
11-09 01:18:14.251: D/AndroidRuntime(275): Shutting down VM
11-09 01:18:14.251: W/dalvikvm(275): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
11-09 01:18:14.261: E/AndroidRuntime(275): FATAL EXCEPTION: main
11-09 01:18:14.261: E/AndroidRuntime(275): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.ssss/com.example.ssss.SearchlistActivity}: java.lang.NullPointerException
11-09 01:18:14.261: E/AndroidRuntime(275): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
11-09 01:18:14.261: E/AndroidRuntime(275): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
11-09 01:18:14.261: E/AndroidRuntime(275): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
11-09 01:18:14.261: E/AndroidRuntime(275): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
11-09 01:18:14.261: E/AndroidRuntime(275): at android.os.Handler.dispatchMessage(Handler.java:99)
11-09 01:18:14.261: E/AndroidRuntime(275): at android.os.Looper.loop(Looper.java:123)
11-09 01:18:14.261: E/AndroidRuntime(275): at android.app.ActivityThread.main(ActivityThread.java:4627)
org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:348)
11-09 00:45:17.072: W/System.err(302): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
11-09 00:45:17.072: W/System.err(302): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
11-09 00:45:17.072: W/System.err(302): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
11-09 00:45:17.072: W/System.err(302): at com.example.sss.JsonParserSearch.getJSONFromUrl(JsonParserSearch.java:38)
11-09 00:45:17.072: W/System.err(302): at com.example.sss.SearchlistActivity.onCreate(SearchlistActivity.java:39)
11-09 00:45:17.072: W/System.err(302): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-09 00:45:17.082: W/System.err(302): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
11-09 00:45:17.082: W/System.err(302): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
11-09 00:45:17.082: W/System.err(302): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
11-09 00:45:17.082: W/System.err(302): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
11-09 00:45:17.082: W/System.err(302): at android.os.Handler.dispatchMessage(Handler.java:99)
11-09 00:45:17.082: W/System.err(302): at android.os.Looper.loop(Looper.java:123)
11-09 00:45:17.082: W/System.err(302): at android.app.ActivityThread.main(ActivityThread.java:4627)
11-09 00:45:17.082: W/System.err(302): at java.lang.reflect.Method.invokeNative(Native Method)
11-09 00:45:17.082: W/System.err(302): at java.lang.reflect.Method.invoke(Method.java:521)
11-09 00:45:17.092: W/System.err(302): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
11-09 00:45:17.092: W/System.err(302): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
11-09 00:45:17.092: W/System.err(302): at dalvik.system.NativeStart.main(Native Method)
11-09 00:45:17.092: E/Buffer Error(302): Error converting result java.lang.NullPointerException
11-09 00:45:17.092: E/JSON Parser finaal(302): Error parsing data org.json.JSONException: End of input at character 0 of
11-09 00:45:17.103: D/AndroidRuntime(302): Shutting down VM
11-09 00:45:17.103: W/dalvikvm(302): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
11-09 00:45:17.112: E/AndroidRuntime(302): FATAL EXCEPTION: main
11-09 00:45:17.112: E/AndroidRuntime(302): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sss/com.example.sss.SearchlistActivity}: java.lang.NullPointerException
11-09 00:45:17.112: E/AndroidRuntime(302): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
11-09 00:45:17.112: E/AndroidRuntime(302): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
11-09 00:45:17.112: E/AndroidRuntime(302): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
11-09 00:45:17.112: E/AndroidRuntime(302): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
11-09 00:45:17.112: E/AndroidRuntime(302): at android.os.Handler.dispatchMessage(Handler.java:99)
11-09 00:45:17.112: E/AndroidRuntime(302): at android.os.Looper.loop(Looper.java:123)
11-09 00:45:17.112: E/AndroidRuntime(302): at android.app.ActivityThread.main(ActivityThread.java:4627)
11-09 00:45:17.112: E/AndroidRuntime(302): at java.lang.reflect.Method.invokeNative(Native Method)
11-09 00:45:17.112: E/AndroidRuntime(302): at java.lang.reflect.Method.invoke(Method.java:521)
11-09 00:45:17.112: E/AndroidRuntime(302): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
11-09 00:45:17.112: E/AndroidRuntime(302): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
11-09 00:45:17.112: E/AndroidRuntime(302): at dalvik.system.NativeStart.main(Native Method)
11-09 00:45:17.112: E/AndroidRuntime(302): Caused by: java.lang.NullPointerException
11-09 00:45:17.112: E/AndroidRuntime(302): at com.example.sss.SearchlistActivity.onCreate(SearchlistActivity.java:44)
11-09 00:45:17.112: E/AndroidRuntime(302): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
11-09 00:45:17.112: E/AndroidRuntime(302): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
11-09 00:45:17.112: E/AndroidRuntime(302): ... 11 more