我是新来的Android和Web服务编程使用Java和我一直有问题连接我的Android应用程序到我的Java Web服务。 我已经在tomcat上部署了web服务,并且它正在连接到我的手机浏览器,但每次尝试从我的Android应用程序连接时,HttpClient都会返回null。REST风格的Web服务json响应在java中返回null
这是我的源代码。
public class ServiceHandler {
static String response = null;
public final static int GET = 1;
public final static int POST = 2;
public ServiceHandler() {
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* */
public String makeServiceCall(String url, int method) {
return this.makeServiceCall(url, method, null);
}
/**
* Making service call
* @url - url to make request
* @method - http request method
* @params - http request params
* */
public String makeServiceCall(String url, int method, List<NameValuePair> params) {
try {
// http client
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpEntity httpEntity = null;
HttpResponse httpResponse = null;
// Checking http request method type
if (method == POST) {
HttpPost httpPost = new HttpPost(url);
// adding post params
if (params != null) {
httpPost.setEntity(new UrlEncodedFormEntity(params));
}
httpResponse = httpClient.execute(httpPost);
} else if (method == GET) {
// appending params to url
if (params != null) {
String paramString = URLEncodedUtils
.format(params, "utf-8");
url += "?" + paramString;
}
HttpGet httpGet = new HttpGet(url);
httpResponse = httpClient.execute(httpGet);
}
httpEntity = httpResponse.getEntity();
response = EntityUtils.toString(httpEntity);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return response;
}
}
private class Authenticate extends AsyncTask<Void, Void, Void>{
@Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(LoginActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
@Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
ServiceHandler sh = new ServiceHandler();
String url = "http://192.168.34.1:8080/SchoolWebService/rest/User/"+username+","+password;
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, ServiceHandler.GET);
Log.d("Response: ", "> " + jsonStr);
if (jsonStr != null) {
try {
JSONObject c = new JSONObject(jsonStr);
String uname = c.getString("username");
String pword = c.getString("password");
snackbar.setText("Authenticated").show();
} catch (JSONException e) {
e.printStackTrace();
}
} else {
snackbar.setText("Authentication Failed!").show();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
}
}
的Log.d(....);语句总是返回null。
除了使用的AsyncTask使用抽射解析JSON数据...... – Manish
我如何不知道要做到这一点 – Charles
我从我的代码做错了什么? – Charles