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我想將檢索到的數據從服務器發送到我的Android客戶端...我使用json對象來完成此操作。這是我的servlet代碼。在servlet中創建json對象
import java.io.IOException;
import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
public class AvailabilityResponse extends HttpServlet {
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("application/json");
PrintWriter out=response.getWriter();
String br_id;
br_id=request.getParameter("branchname");
try{
Class.forName("com.mysql.jdbc.Driver").newInstance();
Connection con=DriverManager.getConnection("jdbc:mysql://localhost:8888/atmlivedetails","root","root");
Statement st=con.createStatement();
ResultSet rs=st.executeQuery("select atmbrno, atmbrname from location_stat where act_brname='"+br_id+"'");
while(rs.next()){
String s = rs.getString("atmbrno");
String t = rs.getString("atmbrname");
JSONObject arrayObj = new JSONObject();
arrayObj.put("atmbrno",s);
arrayObj.put("atmbrname",t);
out.print(arrayObj);
}
rs.close();
st.close();
}
catch(Exception e){
out.print(e);
}
}
}
，這是我的Android端代碼..
import java.util.ArrayList;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.ParseException;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.ClientProtocolException;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.content.Intent;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import android.os.Bundle;
public class CheckAvailability extends Activity{
Button but1,but2;
EditText brName;
TextView txt1;
String text;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.availability);
brName =(EditText)findViewById(R.id.editText1);
but1 = (Button)findViewById(R.id.button5);
but2 = (Button)findViewById(R.id.button6);
txt1 = (TextView)findViewById(R.id.textView3);
but1.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
String result = null;
InputStream is = null;
StringBuilder sb=null;
ArrayList<NameValuePair> postParameters = new ArrayList<NameValuePair>();
postParameters.add(new BasicNameValuePair("branchname", brName.getText().toString()));
//http post
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://10.0.2.2:8080/hello/AvailabilityResponse");
httppost.setEntity(new UrlEncodedFormEntity(postParameters));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}catch(Exception e){
Log.e("log_tag", "Error in http connection"+e.toString());
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
sb = new StringBuilder();
sb.append(reader.readLine() + "\n");
String line="0";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
result=sb.toString();
}catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
//paring data
String atm_id;
String atm_name;
try{
JSONArray jArray = new JSONArray(result);
JSONObject json_data=null;
for(int i=0;i<jArray.length();i++){
json_data = jArray.getJSONObject(i);
atm_id=json_data.getString("atmbrno");
atm_name=json_data.getString("atmbrname");
//txt1.setText(atm_name);
}
}catch(JSONException e1){
Toast.makeText(getBaseContext(), "No DATA Found", Toast.LENGTH_LONG).show();
}catch (ParseException e1){
e1.printStackTrace();
}
}
});
}}
但是當我運行它，它總是給我 「找不到數據」 異常...誰能幫我？？？
你在哪裏得到「無數據發現「在服務器端或Android端的異常？ – ponraj
請重新格式化代碼..刪除不必要的導入和過多的代碼。使它清脆，易於閱讀。 – Nishant
@ ponraj-它顯示在屏幕上...在這裏它添加爲Toast.makeText（getBaseContext（），「No Data Found」，Toast.LENGTH_LONG）.show（）; – Dasaya