如何在脱机时存储mqtt数据，并在联机时发送数据
如何在脱机时存储mqtt数据，并在联机时发送数据
提问于 2016-08-03 07:34:18
我有一个问题，当我的连接被侵入时，mqtt发布不发送在重新连接，如何解决它？我跟随这个答案，但不工作
我做了什么，：
- 我已经实现了一个服务mqtt发送gps定位和工作如常时，在线。
- 将Qos设置为1。
- 设置ClientId修复。
- 将发布Qos设置为1。
- 将干净会话设置为false
但是，当我重新连接时，结果仍然是在联机时发布数据&而不是发布存储的持久性数据。
这里是我的源代码：
package id.trustudio.android.mdm.service;
import android.app.Service;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.pm.ApplicationInfo;
import android.content.pm.PackageManager;
import android.net.TrafficStats;
import android.os.Handler;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.util.Log;
import org.eclipse.paho.android.service.MqttAndroidClient;
import org.eclipse.paho.client.mqttv3.IMqttActionListener;
import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.IMqttToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
import java.io.UnsupportedEncodingException;
import id.trustudio.android.mdm.http.DetectConnection;
import id.trustudio.android.mdm.util.Cons;
import id.trustudio.android.mdm.util.Debug;
import id.trustudio.android.mdm.util.GPSTracker;
import id.trustudio.android.mdm.util.GPSTracker2;
public class MqttService extends Service implements MqttCallback {
public static boolean isStarted = false;
private double latitude = 0;
private double longitude = 0;
private GPSTracker mGPSTracker;
private GPSTracker2 mGPSTracker2;
boolean isInternetPresent = false;
private SharedPreferences mPrivatePref;
private SharedPreferences.Editor editor;
private DetectConnection mDetectConnection;
String deviceID,Name;
int totalbyte;
String packages;
MemoryPersistence persistence;
String clientId;
MqttAndroidClient client;
@Nullable
@Override
public IBinder onBind(Intent intent) {
return null;
}
@Override
public void onCreate() {
super.onCreate();
mPrivatePref = this.getSharedPreferences(Cons.PRIVATE_PREF, Context.MODE_PRIVATE);
editor = mPrivatePref.edit();
deviceID = mPrivatePref.getString(Cons.APP_PACKAGE + "deviceid", "");
Name = mPrivatePref.getString(Cons.APP_PACKAGE + "user", "");
clientId = MqttClient.generateClientId();
persistence = new MemoryPersistence();
client =
new MqttAndroidClient(getApplicationContext(), "tcp://broker.administrasi.id:1883",
clientId, persistence);
client.setCallback(this);
try{
MqttConnectOptions connOpts = new MqttConnectOptions();
connOpts.setCleanSession(false);
client.connect(connOpts,null, new IMqttActionListener() {
@Override
public void onSuccess(IMqttToken asyncActionToken) {
}
@Override
public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
}
});
}catch (Exception e){
e.printStackTrace();
}
mHandler.postDelayed(mUpdateTask, 1000);
}
public int onStartCommand(Intent intent, int flags, int startId) {
int res = super.onStartCommand(intent, flags, startId);
//check if your service is already started
if (isStarted){ //yes - do nothing
return Service.START_STICKY;
} else { //no
isStarted = true;
}
return Service.START_STICKY;
}
private Handler mHandler = new Handler();
private Runnable mUpdateTask = new Runnable() {
public void run() {
getLatLng();
if (latitude == 0.0 || longitude == 0.0) getLatLngWifi();
Debug.e("MQTT","Connect");
String topic = "gps/kodeupi/kodeap/kodeup/" + deviceID;
Debug.e("MQTT CLIENT", clientId);
int qos = 1;
try {
IMqttToken subToken = client.subscribe(topic, qos);
subToken.setActionCallback(new IMqttActionListener() {
@Override
public void onSuccess(IMqttToken asyncActionToken) {
// The message was published
String topic = "gps/kodeupi/kodeap/kodeup/" + deviceID;
long CurrentTime = System.currentTimeMillis();
String payload = deviceID + "|" + latitude + "|" + longitude + "|" + CurrentTime;
byte[] encodedPayload = new byte[0];
try {
encodedPayload = payload.getBytes("UTF-8");
MqttMessage message = new MqttMessage(encodedPayload);
client.publish(topic, message);
message.setRetained(true);
// set quality of service
message.setQos(1);
Log.d("TAG", "onSuccess");
} catch (UnsupportedEncodingException | MqttException e) {
e.printStackTrace();
}
}
@Override
public void onFailure(IMqttToken asyncActionToken,
Throwable exception) {
// The subscription could not be performed, maybe the user was not
// authorized to subscribe on the specified topic e.g. using wildcards
}
});
} catch (MqttException e) {
e.printStackTrace();
}
mHandler.postDelayed(this, 20000);
}
};
private void getLatLng() {
mGPSTracker2 = new GPSTracker2(this);
isInternetPresent = mDetectConnection.isConnectingToInternet();
if (isInternetPresent == true) {
if (mGPSTracker2.canGetLocation()) {
latitude = mGPSTracker2.getLatitude();
longitude = mGPSTracker2.getLongitude();
if(latitude != 0.0 && longitude != 0.0) {
editor.putString(Cons.APP_LATITUDE, latitude+"");
editor.putString(Cons.APP_LONGITUDE, longitude+"");
editor.commit();
}
} else {
// getLatLngWifi();
Debug.i(Cons.TAG, "on gps failed, please check");
}
} else {
Debug.i(Cons.TAG, "no connection");
if(mGPSTracker2 != null)
mGPSTracker2.stopUsingGPS();
}
}
private void getLatLngWifi() {
mGPSTracker = new GPSTracker(this);
isInternetPresent = mDetectConnection.isConnectingToInternet();
if (isInternetPresent == true) {
if (mGPSTracker.canGetLocation()) {
latitude = mGPSTracker.getLatitude();
longitude = mGPSTracker.getLongitude();
if(latitude != 0.0 && longitude != 0.0) {
editor.putString(Cons.APP_LATITUDE, latitude+"");
editor.putString(Cons.APP_LONGITUDE, longitude+"");
editor.commit();
}
} else {
Debug.i(Cons.TAG, "wifi " + "on gps failed, please check");
}
} else {
Debug.i(Cons.TAG, "wifi " + "no connection");
if(mGPSTracker != null)
mGPSTracker.stopUsingGPS();
}
}
@Override
public void connectionLost(Throwable cause) {
}
@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
}
@Override
public void deliveryComplete(IMqttDeliveryToken token) {
}
}抱歉，我的英语不好
回答 2
Stack Overflow用户
回答已采纳
发布于 2016-08-03 11:56:54
如评论中所述。
这是您必须自己编写的东西，不支持存储未发送的消息，因为客户端在框架中断开了连接。MQTT持久性仅用于确保QOS 1/2的消息在运行过程中不会丢失，如果到代理的连接在QOS握手完成之前中断。
如果试图在断开连接时发布消息，client.publish(topic, message)调用将引发异常，则需要捕获此异常，然后安排存储消息的内容，以便在重新建立连接时使用。一旦连接重新启动并运行，那么您需要迭代存储的详细信息并再次尝试发送。
Stack Overflow用户
发布于 2016-08-16 06:14:34
因此，这里的例子，作为硬的答案，我自己做了我自己的实现存储数据到本地数据库，并发送所有在连接重建。
这里是我的源代码
private Handler mHandler = new Handler();
private Runnable mUpdateTask = new Runnable() {
public void run() {
getLatLng();
if (latitude == 0.0 || longitude == 0.0) getLatLngWifi();
Debug.e("MQTT","Connect");
String topic = "gps/kodeupi/kodeap/kodeup/" + deviceID;
Debug.e("MQTT CLIENT", clientId);
int qos = 1;
try {
IMqttToken subToken = client.subscribe(topic, qos);
subToken.setActionCallback(new IMqttActionListener() {
@Override
public void onSuccess(IMqttToken asyncActionToken) {
// The message was published
mList = getLocationAll();//call all data stored on sqlite
Debug.e("MQTT","Connected. Size list = "+mList.size());
if(mList.size() > 0){//if data found then send in looping
for (int i = 0; i < mList.size() ; i++) {
final String Latitude = mList.get(i).latitude;
final String Longitude = mList.get(i).longitude;
final String timestamps = mList.get(i).CurrentTimes;
String payload = deviceID + "|" + timestamps + "|" + Name + "|" + Latitude + "|" + Longitude;
byte[] encodedPayload = new byte[0];
try {
encodedPayload = payload.getBytes("UTF-8");
MqttMessage message = new MqttMessage(encodedPayload);
// set quality of service
client.publish(topic, message);
} catch (UnsupportedEncodingException | MqttException e) {
e.printStackTrace();
}
}
DeleteAllLocation();
}
String topic = "gps/kodeupi/kodeap/kodeup/" + deviceID;
long CurrentTime = System.currentTimeMillis();
String payload = deviceID + "|" + latitude + "|" + longitude + "|" + CurrentTime;
byte[] encodedPayload = new byte[0];
try {
encodedPayload = payload.getBytes("UTF-8");
MqttMessage message = new MqttMessage(encodedPayload);
client.publish(topic, message);
message.setRetained(true);
// set quality of service
message.setQos(1);
Log.d("TAG", "onSuccess");
} catch (UnsupportedEncodingException | MqttException e) {
e.printStackTrace();
}
}
@Override
public void onFailure(IMqttToken asyncActionToken,
Throwable exception) {
// The subscription could not be performed, maybe the user was not
// authorized to subscribe on the specified topic e.g. using wildcards
long CurrentTime = System.currentTimeMillis();
addLocation(deviceID, CurrentTime+"", Name, latitude+"" , longitude+""); //add data to sqlite when offline
Debug.e("MQTT","Failure");
}
});
} catch (MqttException e) {
e.printStackTrace();
}
mHandler.postDelayed(this, 20000);
}
};在这里存储和删除数据
public void addLocation( String device_id, String timestamp, String user_id, String latitude, String longitude) {
if (sqLite == null) {
Debug.i(Cons.TAG, "null database");
return;
}
ContentValues values = new ContentValues();
values.put("device_id", device_id);
values.put("timestamp", timestamp);
values.put("user_id", user_id);
values.put("latitude", latitude);
values.put("longitude", longitude);
Debug.i(Cons.TAG, "Insert location : title = " + device_id);
sqLite.insert("tbl_location", null, values);
}
public ArrayList<LocationModel> getLocationAll() {
ArrayList<LocationModel> result = new ArrayList<LocationModel>();
if (sqLite == null || result == null) {
return result;
}
String sql = "SELECT * FROM tbl_location ORDER BY timestamp ASC";
Cursor c = sqLite.rawQuery(sql, null);
int device_id = c.getColumnIndex("device_id");
int timestamp = c.getColumnIndex("timestamp");
int userid = c.getColumnIndex("user_id");
int latitude = c.getColumnIndex("latitude");
int longitude = c.getColumnIndex("longitude");
if (c != null) {
if (c.moveToFirst()) {
while (c.isAfterLast() == false) {
LocationModel mApps = new LocationModel();
mApps.DeviceId = c.getInt(device_id);
mApps.CurrentTimes = c.getString(timestamp);
mApps.UserId = c.getString(userid);
mApps.latitude = c.getString(latitude);
mApps.longitude = c.getString(longitude);
result.add(mApps);
c.moveToNext();
}
c.close();
}
}
return result;
}
public void DeleteAllLocation() {
if (sqLite == null)
return;
sqLite.delete("tbl_location", null, null);
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/38737217
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