我在javaspring中有一个post服务，我想用它从android客户端获取当前位置并插入mysql数据库。我的邮政服务经过了 swagger 的测试，效果很好。在android中，我有下一个代码：

public class SendActivity extends AppCompatActivity implements View.OnClickListener {
    private Executor executor = Executors.newFixedThreadPool(1);
    private LocationManager locationManager;
    private String provider;
    private static final int REQUEST_LOCATION = 1;
    TextView textView;
    private volatile Handler msgHandler;

    private static final String STATIC_LOCATION =
            "{" +
                    "\"terminalId\":\"%s\"," +
                    "\"latitude\":\"%s\"," +
                    "\"longitude\":\"%s\"" +
                    "}";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_send);

        textView = (TextView) findViewById(R.id.text_location);

        Button sendButton = findViewById(R.id.button_location);
        sendButton.setOnClickListener(this);

        msgHandler = new MsgHandler(this);

    }

    public void onClick(View v) {
        executor.execute(new Runnable() {
            public void run() {
                Message msg = msgHandler.obtainMessage();
                // use MAC addr or IMEI as terminal id
                // read true position
                // replace static coordinates with the ones from the true position
                 msg.arg1 = sendCoordinates("123456", "23.25", "45.02") ? 1 : 0;
                msgHandler.sendMessage(msg);

            }

        });
    }

    private boolean sendCoordinates(String terminalId, String lattitude, String longitude) {
        HttpURLConnection con = null;
        try {

            if (ActivityCompat.checkSelfPermission(SendActivity.this, Manifest.permission.ACCESS_FINE_LOCATION)
                    != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission
                    (SendActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {

                ActivityCompat.requestPermissions(SendActivity.this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_LOCATION);

            } else {
                Location location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

                Location location1 = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);

                Location location2 = locationManager.getLastKnownLocation(LocationManager. PASSIVE_PROVIDER);

                if (location != null) {
                    double latti = location.getLatitude();
                    double longi = location.getLongitude();
                    lattitude = String.valueOf(latti);
                    longitude = String.valueOf(longi);

                    textView.setText("Your current location is"+ "\n" + "Lattitude = " + lattitude
                            + "\n" + "Longitude = " + longitude);

                } else  if (location1 != null) {
                    double latti = location1.getLatitude();
                    double longi = location1.getLongitude();
                    lattitude = String.valueOf(latti);
                    longitude = String.valueOf(longi);

                    textView.setText("Your current location is"+ "\n" + "Lattitude = " + lattitude
                            + "\n" + "Longitude = " + longitude);

                } else  if (location2 != null) {
                    double latti = location2.getLatitude();
                    double longi = location2.getLongitude();
                    lattitude = String.valueOf(latti);
                    longitude = String.valueOf(longi);

                    textView.setText("Your current location is"+ "\n" + "Lattitude = " + lattitude
                            + "\n" + "Longitude = " + longitude);

                }else{

                    Toast.makeText(this,"Unble to Trace your location",Toast.LENGTH_SHORT).show();

                }
            }

            URL obj = new URL("http://192.168.0.102:8085/position/send");
            con = (HttpURLConnection) obj.openConnection();
            con.setRequestMethod("POST");
            con.setRequestProperty("User-Agent", "Mozilla/5.0");
            con.setRequestProperty("Content-Type", "application/json; charset=UTF-8");

            con.setDoOutput(true);
            OutputStream os = con.getOutputStream();
            os.write(String.format(STATIC_LOCATION, terminalId, lattitude, longitude).getBytes());
            os.flush();
            os.close();

            int responseCode = con.getResponseCode();

            if (responseCode == HttpURLConnection.HTTP_OK) { //success
                BufferedReader in = new BufferedReader(new InputStreamReader(
                        con.getInputStream()));
                String inputLine;
                StringBuilder response = new StringBuilder();

                while ((inputLine = in.readLine()) != null) {
                    response.append(inputLine);
                }

                in.close();

                return true;
            } else {
                return false;
            }
        } catch (Exception e) {
//            e.printStackTrace();
            return false;
        } finally {
            if (con != null) {
                con.disconnect();
            }
        }
    }

    private static class MsgHandler extends Handler {
        private final WeakReference<Activity> sendActivity;

        public MsgHandler(Activity activity) {
            sendActivity = new WeakReference<>(activity);
        }

        @Override
        public void handleMessage(Message msg) {
            if (msg.arg1 == 1) {
                Toast.makeText(sendActivity.get().getApplicationContext(),
                        "Success!", Toast.LENGTH_LONG).show();
            } else {
                Toast.makeText(sendActivity.get().getApplicationContext(),
                        "Error!", Toast.LENGTH_LONG).show();
            }
        }
    }
}

我知道我的变量“string terminalid，string latitude”被覆盖，但是这个方法是一个测试方法。每次运行时，我都会收到以下错误消息：

Toast.makeText(sendActivity.get().getApplicationContext(),
                        "Error!", Toast.LENGTH_LONG).show();

我需要一点帮助这个代码，因为我不知道为什么应用程序不能工作。