Develop Reference

java.sql.SQLException Path to ´C:user/Usuario/Documents/javafolders.school.sqlite does not exist

I am writing because I created a computer base application that simple store data in a sqlite database, I used java through eclipse, the problem is that the application works fine on the pc that it was built on as a jar file, but when I distribute the application to my people I get this message on their computer
java.sql.SQLException path to c:user//usuario/documents/school.sqlite does not exist
The question is . How to change the code tomake the application also work in other computers as well and not only on the pc that it was built on?
here is the code I used
import java.sql.*;
import javax.swing.*;
public class sqlConnection {
Connection conn=null;
public static Connection dbConnector()
{
try{
Class.forName("org.sqlite.JDBC");
Connection conn=DriverManager.getConnection("jdbc:sqlite:C:\\Users\\USUARIO\\Documents\\workspace\\School2015.sqlite");
JOptionPane.showMessageDialog(null, "BIENVENIDO! Estás Conectado");
return conn;
}catch (Exception e)
{
JOptionPane.showMessageDialog(null, e);
return null;
}
}
}

Do not use 'C:\Users\USUARIO\Documents\workspace\School2015.sqlite'
Use relative path instead like ..\..\..\workspace\
or if you need to set up path on runtime use it as String which should be given as input parameter to your program

You can use this code.
import java.sql.*;
import javax.swing.*;
public class sqlConnection {
Connection conn=null;
public static Connection dbConnector()
{
try{
Class.forName("org.sqlite.JDBC");
Connection conn=DriverManager.getConnection("jdbc:sqlite:C:\\Users\\USUARIO\\Documents\\workspace\\School2015.sqlite");
JOptionPane.showMessageDialog(null, "BIENVENIDO! Estás Conectado");
return conn;
}catch (Exception e)
{
JOptionPane.showMessageDialog(null, e);
return null;
}}}

NanoHTTPD server on desktop

I'm trying to serve a small file on my desktop using NanoHTTPD. The server starts fine but due to some unknown reason, it is unable to serve files. The same program works fine in Android. Can anyone give me some pointers? It's being more than an hour but I've got no clue. Here is my desktop version of NanoHTTPD server:
package com.desktopserver;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.net.URLConnection;
import java.util.Map;
import com.desktopserver.NanoHTTPD.Response.Status;
public class MainClass {
static int PORT = 8080;
static WebServer MyServer;
static FileInputStream fis;
static BufferedInputStream bis;
public static void main(String[] args) {
MyServer = new WebServer();
try {
MyServer.start();
System.out.println("Webserver Started # PORT:8080");
} catch (IOException e) {
e.printStackTrace();
}
}
public static class WebServer extends NanoHTTPD {
String MIME_TYPE;
public WebServer() {
super(PORT);
}
#Override
public Response serve(String uri, Method method,
Map<String, String> header, Map<String, String> parameters,
Map<String, String> files) {
try {
File file=new File("/home/evinish/Music/Meant_to_live.mp3");
fis = new FileInputStream(file);
bis = new BufferedInputStream(fis);
MIME_TYPE= URLConnection.guessContentTypeFromName(file.getName());
System.out.println("\nMIME TYPE: "+MIME_TYPE);
System.out.println("\nFILE NAME: "+file.getName());
} catch (IOException ioe) {
System.out.println("File IO Exception");
}
return new NanoHTTPD.Response(Status.OK, MIME_TYPE, bis);
}
}
}
I do get this output, but that's it:
Webserver Started # PORT:8080
What am I missing here? Thanks a lot for your help.

Because you don't use "ServerRunner" class. ServerRunner hold you server to until any key press.
But in real application this don't work you want some change in NanoHTTPd file
line no 196 to
myThread.setDaemon(false);

Cannot start VPN using Toyvpn

I'll try to be as descriptive as possible
I'm new to android and i'm making an android application
In that application i'd like to be able to see the address of the HTTP requests going OUT from the mobile (On what website they are heading).
So i've looked around and i found out that to do that , I need to use a VPN and android 4.0+ has a VPNService supplied from google implemented using ToyVPNService
So i got this service and started changing in it so i can use it without the need of using a server
I'd like to work the VPN as follows:
1-Capture the HTTP requests
2-Read their destination
3-Resend them back to their way
So i took the VPNService and i started modifying it so that i don't need an actual server
Here's the code i'm using
package com.example.testingservice;
import android.app.PendingIntent;
import android.app.Service;
import android.content.Intent;
import android.net.VpnService;
import android.os.Handler;
import android.os.Message;
import android.os.ParcelFileDescriptor;
import android.util.Log;
import android.widget.Toast;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.util.Enumeration;
public class SO1 extends VpnService implements Handler.Callback, Runnable {
private static final String TAG = "ToyVpnService";
private Handler mHandler;
private Thread mThread;
private ParcelFileDescriptor mInterface;
#Override
public int onStartCommand(Intent intent, int flags, int startId) {
// The handler is only used to show messages.
if (mHandler == null) {
mHandler = new Handler(this);
}
// Stop the previous session by interrupting the thread.
if (mThread != null) {
mThread.interrupt();
}
// Start a new session by creating a new thread.
mThread = new Thread(this, "ToyVpnThread");
mThread.start();
return START_STICKY;
}
#Override
public void onDestroy() {
if (mThread != null) {
mThread.interrupt();
}
}
#Override
public boolean handleMessage(Message message) {
if (message != null) {
Toast.makeText(this, message.what, Toast.LENGTH_SHORT).show();
}
return true;
}
#Override
public synchronized void run() {
Log.i(TAG,"running vpnService");
try {
runVpnConnection();
} catch (Exception e) {
e.printStackTrace();
//Log.e(TAG, "Got " + e.toString());
} finally {
try {
mInterface.close();
} catch (Exception e) {
// ignore
}
mInterface = null;
mHandler.sendEmptyMessage(R.string.disconnected);
Log.i(TAG, "Exiting");
}
}
private boolean runVpnConnection() throws Exception {
configure();
FileInputStream in = new FileInputStream(mInterface.getFileDescriptor());
// Allocate the buffer for a single packet.
ByteBuffer packet = ByteBuffer.allocate(32767);
// We keep forwarding packets till something goes wrong.
while (true) {
// Assume that we did not make any progress in this iteration.
boolean idle = true;
// Read the outgoing packet from the input stream.
int length = in.read(packet.array());
if (length > 0) {
Log.i(TAG,"************new packet");
System.exit(-1);
while (packet.hasRemaining()) {
Log.i(TAG,""+packet.get());
//System.out.print((char) packet.get());
}
packet.limit(length);
// tunnel.write(packet);
packet.clear();
// There might be more outgoing packets.
idle = false;
}
Thread.sleep(50);
}
}
public String getLocalIpAddress()
{
try {
for (Enumeration<NetworkInterface> en = NetworkInterface.getNetworkInterfaces(); en.hasMoreElements();) {
NetworkInterface intf = en.nextElement();
for (Enumeration<InetAddress> enumIpAddr = intf.getInetAddresses(); enumIpAddr.hasMoreElements();) {
InetAddress inetAddress = enumIpAddr.nextElement();
Log.i(TAG,"****** INET ADDRESS ******");
Log.i(TAG,"address: "+inetAddress.getHostAddress());
Log.i(TAG,"hostname: "+inetAddress.getHostName());
Log.i(TAG,"address.toString(): "+inetAddress.getHostAddress().toString());
if (!inetAddress.isLoopbackAddress()) {
//IPAddresses.setText(inetAddress.getHostAddress().toString());
Log.i(TAG,"IS NOT LOOPBACK ADDRESS: "+inetAddress.getHostAddress().toString());
return inetAddress.getHostAddress().toString();
} else{
Log.i(TAG,"It is a loopback address");
}
}
}
} catch (SocketException ex) {
String LOG_TAG = null;
Log.e(LOG_TAG, ex.toString());
}
return null;
}
private void configure() throws Exception {
// If the old interface has exactly the same parameters, use it!
if (mInterface != null) {
Log.i(TAG, "Using the previous interface");
return;
}
// Configure a builder while parsing the parameters.
Builder builder = new Builder();
String SS=getLocalIpAddress();
builder.setMtu(1500);
// builder.addAddress("10.0.0.2", 24);
builder.addAddress(SS, 24);
// builder.addAddress(SS,24);
builder.addRoute("0.0.0.0",0);
try {
mInterface.close();
} catch (Exception e) {
// ignore
}
mInterface = builder.establish();
}}
The problem is this line
mInterface = builder.setSession("GITVPN").setConfigureIntent(mConfigureIntent).establish();
the Establish returns NULL and i can't seem to get it working
I'm thinking there is a problem with the addresses
I'd like to work it that there's no server , and there would be a tunnel that reads the packets
I've seen some other post that said i should make the addresses to 10.0.0.2 instead of external ips ( 192.168.x.x) and i should add route (0.0.0.0,0)
However the descriptor file keeps returning null and i can't seem to fix it
Any help will be appreciated , and sorry if this sounded that it was repeated but i'm super stuck and you guys are my only hope

You can't run the VpnService and establish a VPN connection without having a server that you communicate with and forwards the traffic to the internet.

Check the IP address you assigned to the interface, it should not be the same as other adapters.
What the builder operated on is a TUN device, which is created for VPN service.
So, IP address of the TUN should be proper set.
Make the address conflict with others is not a good idea.
Also, Step 3 you mentioned is not quite easy as Android not support raw socket.

just to revive an old thread...
VpnService requires a users interaction to start and won't work without it
the ToyVpnClient puts a button on the screen that the user has to click and once that's done, the Builder method will return the interface
so, steps to make it work are;
1. build a button on your app
2. onclick of that button, call VpnService.prepare(this); (this = your app context)
3. Builder.establish() will now return a VPN interface

ReadInputDiscretesResponse error (Jamod,Android)

I'm using the library Jamod and I have trouble reading the record, what I want is to read only the record number 300 PLC I'm connected, but I get read error (enters the catch). Thanks for your help
package com.JR.scada;
import java.net.InetAddress;
import net.wimpi.modbus.Modbus;
import net.wimpi.modbus.io.ModbusTCPTransaction;
import net.wimpi.modbus.msg.ReadInputDiscretesRequest;
import net.wimpi.modbus.msg.ReadInputDiscretesResponse;
import net.wimpi.modbus.msg.ReadMultipleRegistersResponse;
import net.wimpi.modbus.net.TCPMasterConnection;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class Main extends Activity{
TextView text, depurar;
EditText IP;
Button boton;
int i=0;
TCPMasterConnection con = null; //the TCP connection
ModbusTCPTransaction trans = null; //the Modbus transaction
InetAddress addr = null; //direccion del esclavo
int port = Modbus.DEFAULT_PORT;//puerto por defecto 502
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text = (TextView) findViewById(R.id.lblRegistro);
IP = (EditText) findViewById(R.id.txtIp);
depurar = (TextView) findViewById(R.id.txtdepurar);
boton = (Button)findViewById(R.id.btnVerRegistro);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
protected void onStop() {
super.onStop();
//Close the TCP connection
con.close();
}
public class conectar extends AsyncTask<String,String,Integer>{
ReadInputDiscretesRequest req = null; //the request
ReadInputDiscretesResponse res = null; //the response
int startReg;
protected void onPreExecute() {
try {
//IP address;
addr = InetAddress.getByName("212.170.50.238");
} catch (Exception e) {
Log.d("MODBUS","IP error", e);
}
}
protected Integer doInBackground(String... urls) {
try {
// Open the connection
con = new TCPMasterConnection(addr);
con.setPort(port);
con.connect ();
try {
startReg = 300;
// Prepare the request
req = new ReadInputDiscretesRequest (startReg, 1);
// Prepare the transaction
trans = new ModbusTCPTransaction(con);
trans.setRequest(req);
// execute the transaction
trans.execute();
// get the response
res = (ReadInputDiscretesResponse) trans.getResponse ();
} catch (Exception e) {
Log.d("MODBUS", "Error in reading/writing");
return 1;
}
} catch (Exception e) {
Log.d("MODBUS","connection error", e);
return 1;
}
return 0;
}
protected void onPostExecute(Integer bytes) {
if(con.isConnected()){
depurar.setText("conecta");
}
text.setText("Digital Inputs Status=" + res.getDiscretes ().toString () );
}
}
public void onClick(View v) {
// int startReg;
conectar conectamos = new conectar();
conectamos.execute("hola");
}
error:
08-21 10:01:57.554: D/MODBUS(3322): Error in reading/writing

Without knowing more about the modbus configuration on your slave PLC, my first suggestion is to try a different value for startReg, and see if the error persists. This will rule out problems with your Java.
Some test numbers that should work: 0,1,7,8
They may not all work, but at least one of them should return successfully.
If none of them return successfully, there may be a problem on the PLC configuration, or a problem with your request code.
If one of the test numbers is successful, you should post your results. If so, this means that you are attempting to access a memory location that does not exist on the PLC. If you access undefined PLC memory locations, often the PLC will abort the request (it does not just send back '0').
Followup remarks:
If you find that your code works when using different values for startReg, but not for 300, the reason has to do with memory mapping on the PLC, and this can be different for each brand/model of PLC (post your PLC brand/model if available).
You say in your question 'record 300'. When working with PLC, you usually don't refer to memory as a record. Are you trying to access Bit 300, Byte 300, Word 300, DoubleWord 300?
The real question you need to be asking, is 300 the actual modbus address you want to read, or is 300 how the PLC address is mapped (such as the 300th I/O slot, not necessarily the 300th WORD). It may be required to convert between octal, decimal, and hexidecimal addresses. Or, you may need to re-index an address (some PLCs like to start counting at 1, but generally modbus starts counting at 0).
Perhaps you meant to read BIT 300 (not record 300), which would then be 12th BIT in the 18th WORD, so it would look like this:
//
startReg = 17;
// Prepare the request
// Your 300th bit should be the last value returned.
req = new ReadInputDiscretesRequest (startReg, 12);
The different values I suggested for startReg are meant to help you discover how your PLC Inputs are mapped into modbus addresses by your Java library. This might help with number conversions.

If you keep getting exceptions in your catch block, you might want to find out more about the error.
Try changing this line from your original code:
try {
//...
} catch (Exception e) {
Log.d("MODBUS", "Error in reading/writing");
return 1;
}
into this:
try {
//...
} catch (Exception e) {
Log.d("MODBUS", e.getMessage() );
return 1;
}
Hopefully the exception will tell you more about exactly why its failing. Post those results.
If you are getting a NULL message, you might try using a debugger to manually inspect your connection instance.

AsyncTask creation causes crash

Having some issues with a custom class that extends AsyncTask. My app is Targeting Android 4.0.3 and the below code works fine for 30+ people testing it. However there are two users that are seeing the app crash when I call new AsyncRequest like below.
I've got a working logger that is recording to a text file on the users storage and doesn't record the entry that is in the AsyncRequest constructor. So I have to assume that the crash is happening before the constructor is called.
One of the two devices that are experiencing this crash is running Android 4.0.4 apparently. Not sure what the other device is running. Unfortunately I dont' have access to the two devices so can't see a logcat output.
Any input as to why the object creation is causing a crash would be greatly appreciated.
String url = "www.google.com";
new AsyncRequest(callback, context).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, url);
And here is the full AsyncRequest class
public class AsyncRequest extends AsyncTask<String, String, String>{
HttpURLConnection connection;
InputStream inStream;
IApiCallback callback;
Context context_;
public AsyncRequest(IApiCallback callback, Context context) {
// Log entry added for testing. Never gets called.
FileLogger.getFileLogger(context).ReportInfo("Enter AsyncRequest Constructor");
this.callback = callback;
context_ = context;
}
#Override
protected String doInBackground(String... uri) {
try {
URL url = new URL(uri[0] + "?format=json");
FileLogger.getFileLogger(context_).ReportInfo("Async Request: Sending HTTP GET to " + url);
connection = (HttpURLConnection) url.openConnection();
connection.setConnectTimeout(5000);
connection.setReadTimeout(5000);
connection.addRequestProperty("Accept-Encoding", "gzip");
connection.addRequestProperty("Cache-Control", "no-cache");
connection.connect();
String encoding = connection.getContentEncoding();
// Determine if the stream is compressed and uncompress it if needed.
if (encoding != null && encoding.equalsIgnoreCase("gzip")) {
inStream = new GZIPInputStream(connection.getInputStream());
} else {
inStream = connection.getInputStream();
}
if (inStream != null) {
// process response
BufferedReader br = new BufferedReader(new InputStreamReader(inStream));
StringBuilder sb = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
sb.append(line);
}
return sb.toString();
}
} catch (SocketTimeoutException e) {
FileLogger.getFileLogger(context_).ReportException("Async Request: SocketTimeoutException", e);
Log.i("AsyncRequest", "Socket Timeout occured");
} catch (MalformedURLException e) {
FileLogger.getFileLogger(context_).ReportException("Async Request: MalformedUrlException", e);
} catch (IOException e) {
FileLogger.getFileLogger(context_).ReportException("Async Request: IOException", e);
Log.i("doInBackground:","IOException");
if (e != null && e.getMessage() != null) {
Log.i("doInBackground:",e.getMessage());
}
} catch (Exception e) {
FileLogger.getFileLogger(context_).ReportException("Async Request: Exception", e);
} finally {
if (connection != null)
connection.disconnect();
}
return null;
}
#Override
protected void onPostExecute(String result) {
if (result != null)
FileLogger.getFileLogger(context_).ReportInfo("Async Request: Response is valid");
else
FileLogger.getFileLogger(context_).ReportInfo("Async Request: Invalid response");
callback.Execute(result);
}
}
EDIT: As per comments below.
Here is the full method that I call my custom AsyncTask from. All the logging messages I have up to creating the AsyncTask are showing in the log. None of the exceptions are.
The logging displays the url value just before creating my AsyncRequest and the URL is not malformed at all. It's what I'm expecting.
public void GetServerInfoAsync(IApiCallback callback, Context context) throws IllegalArgumentException, Exception {
if (callback == null)
throw new IllegalArgumentException("callback");
if (context == null)
throw new IllegalArgumentException("context");
try {
FileLogger.getFileLogger(context).ReportInfo("Build URL");
String url = GetApiUrl("System/Info");
FileLogger.getFileLogger(context).ReportInfo("Finished building URL");
if (url != null) {
FileLogger.getFileLogger(context).ReportInfo("GetServerInfoAsync: url is " + url);
new AsyncRequest(callback, context).executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, url);
} else {
FileLogger.getFileLogger(context).ReportError("GetServerInfoAsync: url is null");
}
} catch (IllegalArgumentException iae) {
FileLogger.getFileLogger(context).ReportException("GetServerInfoAsync: IllegalArgumentException", iae);
throw iae;
} catch (Exception e) {
FileLogger.getFileLogger(context).ReportException("GetServerInfoAsync: Exception", e);
throw e;
}
}

First of all, just keep in mind that executeOnExecutor() is not available prior to Api 11. You have already said the issue is with a 4.0.4 device, but just keep this in mind.
Here are the steps I would take in order to troubleshoot what the problem is. It seems as if you have already done a few of these with all those ReportInfo() statements.
First, I assume your call to GetServerInfoAsync is within a try...catch, correct? I am checking because of your use of Throw. Also, you have already added logging to check for errors with the url. Since the errors occur before you actually use it, the error cannot be with the url, or any internet permissions.
You call the AsyncTask generation with references to callback and context. You have added logging via ReportInfo() which references context, and those work, yes? Therefore, context is not your issue. However, you never check what callback is. You throw an error if it is null, but you never do anything with it before you call AsyncRequest. Try a ReportInfo(callback.toString()) to see what it is.
If all else fails, it would seem to be an error with threading. Why not try using just AsyncTask, instead of executeOnExecutor(). Do you really need more than 1 background thread?

Sorry for not getting back to this sooner. There were numerous issues here.
First off... Thanks to Wolfram's suggestion I was able to catch the exception and diagnose that the issue was that my FileLogger (and another class) was a static reference and these two tablets couldn't find the reference at runtime. So I ended up removing Logging from my async methods.
Secondly, after making the above changes there was another issue which was that a looper had to be called from the main thread. It turned out that these two tablets weren't calling my async task from the main thread. So I had to enclose the async call in a new Handler using the MainLooper.