PHP和Android中的不同解决方案

I am trying to make an android login app,where the login credentials of different users are in database.

    <?php
    require_once('conn2.php');
    $username=$_GET['username'];
    $password=$_GET['pass'];
    $sql = "SELECT * FROM user_login WHERE Id='$username' and  Password='$password'";

    $res = mysqli_query($con,$sql);
    $check = mysqli_fetch_row($res);

    if(isset($check)){
    echo 'success';
    }
    else{
    echo $username,$password;
    }
    mysqli_close($con);
    ?>

The conn2.php is used to connect to the database.(No problem in that)

    package com.example.chili_32.apollotyres;

    import android.content.Context;
    import android.content.Intent;
    import android.net.Uri;
    import android.os.AsyncTask;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.FrameLayout;
    import android.widget.TextView;
    import android.widget.Toast;

    import com.example.chili_32.apollotyres.Connection.Config;
    import com.example.chili_32.apollotyres.Connection.RequestHandler;

    import org.json.JSONArray;
    import org.json.JSONException;
    import org.json.JSONObject;

    public class Login_page extends AppCompatActivity {
    private static EditText Username;
    private static EditText Password;
    private static Button Sign_In;
    private static FrameLayout Apollo;
    TextView forgot;
    Context context;
    String JSON_STRING,pass,username;
    int counter = 5;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login_page);
    Loginbutton();
}
public void Loginbutton(){
    forgot = (TextView)findViewById(R.id.fp);
    Username = (EditText)findViewById(R.id.editText_Name);
    Password = (EditText)findViewById(R.id.editText_password);
    Sign_In = (Button)findViewById(R.id.signin);
    Apollo = (FrameLayout)findViewById(R.id.apollo);
    forgot.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Toast.makeText(Login_page.this,".....",Toast.LENGTH_SHORT).show();
        }
    });
    Apollo.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent zed = new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.apollotyres.com"));
                    startActivity(zed);
                }
            }
    );
    Sign_In.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    getJSON();
                                       }
            }
    );}
private void getJSON() {
    username=Username.getText().toString().trim();
    pass=Password.getText().toString().trim();
    Toast.makeText(Login_page.this, username+pass, Toast.LENGTH_SHORT).show();
    class GetJSON extends AsyncTask<Void, Void, String> {
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            JSON_STRING = s;
            if (JSON_STRING=="success") {
                Toast.makeText(Login_page.this, "Logging In",
                        Toast.LENGTH_SHORT).show();
                Intent abc = new Intent("com.example.chili_32.apollotyres.Home");
                startActivity(abc);

            }
            else {
                Toast.makeText(Login_page.this, "Incorrect Username or Password"+JSON_STRING, Toast.LENGTH_LONG).show();
                counter--;
                if (counter == 0) {
                    Sign_In.setEnabled(false);
                }
            }

        }

        @Override
        protected String doInBackground(Void... params) {
            RequestHandler rh = new RequestHandler(context);
            return rh.sendGetRequestParam3(Config.URL_LOGIN,username,pass);
        }
    }
    GetJSON gj = new GetJSON();
    gj.execute();
}
private void login(){
    JSONObject jsonObject;
    try{
        jsonObject = new JSONObject(JSON_STRING);
        JSONArray result = jsonObject.getJSONArray(Config.TAG_JSON_ARRAY);
        for(int i = 0;i<result.length();i++) {
            JSONObject jo = result.getJSONObject(i);

            String password = jo.getString("Password");
            Toast.makeText(Login_page.this, password, Toast.LENGTH_SHORT).show();

        }

    } catch (JSONException e) {
        e.printStackTrace();
    }
}
    }

This is the code for RequestHandler Class

      package com.example.chili_32.apollotyres.Connection;
      import android.content.Context;
      import java.io.BufferedReader;
      import java.io.BufferedWriter;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.io.OutputStream;
    import java.io.OutputStreamWriter;
    import java.io.UnsupportedEncodingException;
    import java.net.HttpURLConnection;
    import java.net.URL;
    import java.net.URLEncoder;
    import java.util.HashMap;
    import java.util.Map;

    import javax.net.ssl.HttpsURLConnection;

    public class RequestHandler {
    Context context;

    public RequestHandler(Context context) {
    this.context = context;
    }

    public String sendPostRequest(String requestURL,
                              HashMap<String, String> postDataParams) {


    StringBuilder sb = new StringBuilder();
    try {
        URL url = new URL(requestURL);

        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("POST");
        conn.setDoInput(true);
        conn.setDoOutput(true);

        OutputStream os = conn.getOutputStream();
        BufferedWriter writer = new BufferedWriter(
                new OutputStreamWriter(os, "UTF-8"));
        writer.write(getPostDataString(postDataParams));

        writer.flush();
        writer.close();
        os.close();
        int responseCode = conn.getResponseCode();

        if (responseCode == HttpsURLConnection.HTTP_OK) {
            InputStream is = conn.getInputStream();
            BufferedReader br = new BufferedReader(new InputStreamReader(is, "iso-8859-1"));
            String response;
            while ((response = br.readLine()) != null) {
                sb.append(response);
            }
        }

    } catch (Exception e) {
        e.printStackTrace();
    }
    return sb.toString();

}

public String sendGetRequest(String requestURL) {
    StringBuilder sb = new StringBuilder();
    try {
        URL url = new URL(requestURL);
        HttpURLConnection con = (HttpURLConnection) url.openConnection();
        con.setDoInput(true);
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));

        String s;
        while ((s = bufferedReader.readLine()) != null) {
            sb.append(s + "
");
        }
    } catch (Exception e) {
    }
    return sb.toString();
}
public String sendGetRequestParam(String requestURL, String id){
    StringBuilder sb =new StringBuilder();
    try {
        URL url = new URL(requestURL+id);
        HttpURLConnection con = (HttpURLConnection) url.openConnection();
        con.setDoInput(true);
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));

        String s;
        while((s=bufferedReader.readLine())!=null){
            sb.append(s+"
");
        }
    }catch(Exception e){
    }
    return sb.toString();
}

public String sendGetRequestParam2(String requestURL, String id,int size){
    StringBuilder sb =new StringBuilder();
    try {
        URL url = new URL(requestURL+id+size);
        HttpURLConnection con = (HttpURLConnection) url.openConnection();
        con.setDoInput(true);
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));

        String s;
        while((s=bufferedReader.readLine())!=null){
            sb.append(s+"
");
        }
    }catch(Exception e){
    }
    return sb.toString();
}

public String sendGetRequestParam3(String requestURL, String id,String pass){
    StringBuilder sb =new StringBuilder();
    try {
        URL url = new URL(requestURL+id+pass);
        HttpURLConnection con = (HttpURLConnection) url.openConnection();
        con.setDoInput(true);
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(con.getInputStream()));

        String s;
        while((s=bufferedReader.readLine())!=null){
            sb.append(s+"
");
        }
    }catch(Exception e){
    }
    return sb.toString();
}


private String getPostDataString(HashMap<String, String> params) throws UnsupportedEncodingException {
    StringBuilder result = new StringBuilder();
    boolean first = true;
    for (Map.Entry<String, String> entry : params.entrySet()) {
        if (first)
            first = false;
        else
            result.append("&");

        result.append(URLEncoder.encode(entry.getKey(), "UTF-8"));
        result.append("=");
        result.append(URLEncoder.encode(entry.getValue(), "UTF-8"));
    }

    return result.toString();
}
   }

The Config.java class has all the URLS and final static variables.Config.URL_Login is the url of login page.I declared some final static variables in it as I will be using very often in the code. Eg: Config.TAG_JSON_ARRAY = "result";

This is the xml file

   <?xml version="1.0" encoding="utf-8"?>
   <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:paddingBottom="@dimen/activity_vertical_margin"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   tools:context="com.example.chili_32.apollotyres.Login_page"
   android:background="@drawable/nat">

   <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="Username   :"
    android:id="@+id/textView_Username"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="71dp" />

    <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="Password   :"
    android:id="@+id/textView_Password"
    android:layout_below="@+id/textView_Username"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_alignParentTop="false"
    android:paddingTop="10dp" />

    <EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="textPersonName"
    android:ems="10"
    android:id="@+id/editText_Name"
    android:layout_above="@+id/editText_password"
    android:layout_toRightOf="@+id/signin"
    android:layout_toEndOf="@+id/signin" />

    <EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="textPassword"
    android:ems="10"
    android:id="@+id/editText_password"
    android:layout_alignTop="@+id/textView_Password"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:layout_alignLeft="@+id/editText_Name"
    android:layout_alignStart="@+id/editText_Name" />

    <Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="SIGN IN"
    android:id="@+id/signin"
    android:layout_centerVertical="true"
    android:layout_marginLeft="100dp" />

    <FrameLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentBottom="true"
    android:layout_below="@+id/signin"
    android:layout_marginTop="100dp"
    android:id="@+id/apollo"></FrameLayout>

    <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceSmall"
    android:text="Forgot Password?"
    android:id="@+id/fp"
    android:layout_below="@+id/editText_password"
    android:layout_alignLeft="@+id/editText_password"
    android:layout_alignStart="@+id/editText_password"
    android:textColorHighlight="#5555"/>


     </RelativeLayout>

Well,when I use the URL http://localhost/login.php?username=2013A8PS454H&pass=anvhesh It shows success.But in my application ,as I mentioned in the code,it is displaying username and password. I'm struck here it would be great if anyone helps.