org.json.json异常输入结束于的第1个字符

hi我正在尝试从mysql数据库中检查用户名和密码，在那里我使用md5（）哈希插入了我的密码，现在我想访问这个用户名和密码。我要

"org.json.json在的字符1处输入的异常结束

错误。

这是我的php代码。

    <?php
error_reporting(E_ALL^E_NOTICE^E_WARNING);
$dbhost="localhost";
$dbuser="dev";
$dbpass="dev";
$dbdb="myandroid";
$connect =mysql_connect($dbhost,$dbuser,$dbpass) or die("connection error");
mysql_select_db($dbdb) or die("database selection error");
$username=$_POST["username"];
$password=$_POST["password"];
$pass=md5('$password');
$query=mysql_query("SELECT * FROM androidtable WHERE username='$username' AND password='$pass'")or die(mysql_error());
$num=mysql_num_rows($query);
if($num==1){
while($list=mysql_fetch_assoc($query)){
$output=$list;
echo json_encode($output);
}
mysql_close();
}
?>

安卓代码

public class DBActivity extends Activity implements OnClickListener{
EditText eduser, edpass;
Button logbutton;
String username, password;
HttpClient httpclient;
HttpPost httppost;
ArrayList<NameValuePair> nameValuePair;
HttpResponse httpresponse;
HttpEntity httpentity;
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_db);
    initialise();

}
private void initialise() {
    eduser=(EditText) findViewById(R.id.eduser);
    edpass=(EditText) findViewById(R.id.edpass);
    logbutton=(Button) findViewById(R.id.login);
    logbutton.setOnClickListener(this); 
}
public void onClick(View v) {
    httpclient=new DefaultHttpClient();
    httppost=new HttpPost("http://192.168.1.2/androidtut/check.php");
    username=eduser.getText().toString();
    password=edpass.getText().toString();

    try{
        nameValuePair=new ArrayList<NameValuePair>();
        nameValuePair.add(new BasicNameValuePair("username", username));
        nameValuePair.add(new BasicNameValuePair("password", password));
        httppost.setEntity(new UrlEncodedFormEntity(nameValuePair));
        httpresponse=httpclient.execute(httppost);
        if(httpresponse.getStatusLine().getStatusCode()==200){
            httpentity=httpresponse.getEntity();
            if(httpentity != null){
                InputStream is=httpentity.getContent();
                JSONObject jresp=new JSONObject(convertStreamToString(is));
                String retUser=jresp.getString("username");
                String retPass=jresp.getString("password");
                if(username.equals(retUser) && password.equals(retPass)){
                    SharedPreferences sp=getSharedPreferences("tableandroid",0);
                    SharedPreferences.Editor spedit=sp.edit();
                    spedit.putString("username", username);
                    spedit.putString("password", password);
                    spedit.commit();
                    Toast.makeText(getBaseContext(), "loggin success",Toast.LENGTH_LONG).show();
                }else{
                    Toast.makeText(getBaseContext(), "user invalid",Toast.LENGTH_LONG).show();
                }
            }
        }
    }catch(Exception e){
        String error=e.toString();
        Toast.makeText(getBaseContext(), error,Toast.LENGTH_LONG).show();
    }

}
private static String convertStreamToString(InputStream is) {
    /*
     * To convert the InputStream to String we use the BufferedReader.readLine()
     * method. We iterate until the BufferedReader return null which means
     * there's no more data to read. Each line will appended to a StringBuilder
     * and returned as String.
     */
    BufferedReader reader = new BufferedReader(new InputStreamReader(is));
    StringBuilder sb = new StringBuilder();
    String line = null;
    try {
        while ((line = reader.readLine()) != null) {
            sb.append(line + "'n");
        }
    } catch (IOException e) {
        e.printStackTrace();
    } finally {
        try {
            is.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
    return sb.toString();
}

}