after some research I figured out the easiest way for me to download an image and store it into a file.
This is my code so far:
public boolean descargarArchivo(String url, String outputDirectory) {
try {
File img = new File(outputDirectory);
URLConnection conn = new URL(url).openConnection();
conn.connect();
try (InputStream in = conn.getInputStream();
OutputStream out = new FileOutputStream(img)) {
int b = 0;
while (b != -1) {
b = in.read();
if (b != -1) {
out.write(b);
}
}
}
return true;
} catch (IOException ioe) {
ioe.printStackTrace();
}
return false;
}
The issue with this code, is that it sometimes performs a wrong download of the picture. Let me clear the idea with an example:
While the first picture is the original image (and the output file should be like that), the second picture is the real output file of the image, performed by that code, which is, clearly wrong (ignore the resolution, I'm just talking about this "wrong pixels"). Is there any way to improve this? Should I change the way to download images from the web?
This is how I read images from a URL:
try {
final InputStream inputStream = createInputStream(new URL(getImgUrl()));
try {
return ImageIO.read(inputStream);
} finally {
inputStream.close();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (SocketTimeoutException e) {
//e.printStackTrace(); in case of error, will try again
} catch (IOException e) {
e.printStackTrace();
}
using
protected InputStream createInputStream(URL url) throws IOException {
URLConnection con = url.openConnection();
con.setConnectTimeout(500);
con.setReadTimeout(200);
return con.getInputStream();
}
Related
I'm building a project in which I want a method to make a simple http GET request in order to send two variables to an website via URL.
In a normal java project I would likely use java.net or apache and solve the issue in a matter of minutes. In JavaME, due to my lack of experience I'm not really being able to fulfill the task.
Basically what I want to do is having an url like google.com/index.php?v1=x&v=y
being able to do a get request in order to send those variables via URL.
Any tips?
Here's an example of how you could do something like that.
HttpConnection connection = null;
InputStream inputstream = null;
String url = null;
StringBuffer dataReceived = null;
url = "http://www.google.com/index.php?v1=x&v=y";
dataReceived = new StringBuffer();
try {
connection = (HttpConnection) Connector.open(url);
connection.setRequestMethod(HttpConnection.GET);
connection.setRequestProperty("Content-Type", "text/plain");
connection.setRequestProperty("Connection", "close");
if (connection.getResponseCode() == HttpConnection.HTTP_OK) {
inputstream = connection.openInputStream();
int ch;
while ((ch = inputstream.read()) != -1 ) {
dataReceived.append((char) ch);
}
} else {
// Connection not ok
}
} catch (Exception e) {
// Something went wrong
} finally {
if (inputstream != null) {
try {
inputstream.close();
} catch (Exception e) {
}
}
if (connection != null) {
try {
connection.close();
} catch (Exception e) {
}
}
}
Note: I didn't test this specific code. I just edited some code I had lying around from a previous project of mine, so you may need to fix a few errors.
I was trying to implement the functionality of transferring local files to a network drive using jcifs library but upon running the program on the command line I was receiving following exception:
Exception in thread "main" java.lang.NullPointerException
jcifs.smb.ServerMessageBlock.writeString(ServerMessageBlock.java: 202)
To understand the error I tried debugging the code on eclipse and while doing so at line:
NtlmPasswordAuthentication authentication = new NtlmPasswordAuthentication("xxxxxx.xx.com",username,password);
I received an exception stating ClassNotFoundException. But I have the jcifs.jar in the build path.
A quick google search for 'ntlmpasswordauthentication' classnotfoundexception landed me on two threads with same issue but no resolution.
Please let me know how can I resolve this.
Thank you
Here is the whole function, just in case needed:
private static void TransferFiles()
{
File transfer_files = new File (sourcepath);
File[] files = transfer_files.listFiles();
String username = properties.getProperty("user");
String password = properties.getProperty("password");
String source = sourcepath;
SmbFileOutputStream outputStream = null;
FileInputStream inputStream = null;
SmbFile copyFile = null;
byte[] buffer = new byte[16*1024*1024];
int length = 0;
jcifs.smb.NtlmPasswordAuthentication authentication = new NtlmPasswordAuthentication("xxxxxxx",username,password);
try
{
copyFile = new SmbFile(destinationpath,authentication);
}
catch (MalformedURLException e)
{
e.printStackTrace();
}
try
{
outputStream = new SmbFileOutputStream(copyFile);
}
catch (SmbException | MalformedURLException | UnknownHostException e)
{
e.printStackTrace();
}
try
{
inputStream = new FileInputStream(sourceFile);
}
catch (FileNotFoundException e1)
{
e1.printStackTrace();
}
try
{
while((length = inputStream.read(buffer))>0)
{
outputStream.write(buffer, 0, length);
}
}
catch (IOException e)
{
e.printStackTrace();
}
try
{
inputStream.close();
outputStream.close();
}
catch (IOException e)
{
e.printStackTrace();
}
I have a class called RetreiveHttpStringResponse. It's used to get an InputStream from an URL containing JSON data. The class extends AsyncTask<String, Void, InputStream>. So the strange problem here is that null is always returned. No matter what. There is even no Exception. I checked out the program behaviour with the debugger and could see that at point (1) the processing is jumping immediately to the finally-statement and continues with return null;. And again there are no Errors and no Exceptions are going on. The programm is running normally.
I'm using Android 4.4 (SDK version 19), the response code is 200 and the following lines are set in the Manifest file.
uses-permission android:name="android.permission.INTERNET"
uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"
The problem is happening on the emulator and on a real device with internet connection. Here is the code:
#Override
protected InputStream doInBackground(String... arg0) {
URL url = null;
InputStream is = null;
HttpURLConnection urlConn = null;
int responseCode = 0;
try {
url = new URL(arg0[0]);
urlConn = (HttpURLConnection) url.openConnection();
urlConn.setReadTimeout(10000);
urlConn.setConnectTimeout(15000);
urlConn.setRequestMethod("GET");
urlConn.connect();
responseCode = urlConn.getResponseCode();
Log.d("DataHandlerInternet:RESPONSE_CODE", "The response is: " + responseCode);
is= urlConn.getInputStream(); //-->(1)<--
return is;
}
catch ( MalformedURLException e ) { // new URL() went wrong!
//TODO error message. URL is not correct!
e.printStackTrace();
}
catch (SocketTimeoutException e) { // Timeout while connecting or holding connection to URL.
//TODO error message. Timeout happened!
e.printStackTrace();
}
catch ( IOException e ) { // openConnection() failed!
//TODO error message. Couldn't connect to URL!
e.printStackTrace();
}
catch( Exception e ) { // Any other Exception!
e.printStackTrace();
}
finally {
try { if(is != null) { is.close(); } } catch(Exception e) {e.printStackTrace();}
try { if(urlConn != null) { urlConn.disconnect(); } } catch(Exception e) {e.printStackTrace();}
}
return null;
}
One bad solution is to delete the finally-statement. Well, not the best way to solve this problem.
Now I changed the code. I've put the reading in it and return just the String.
#Override
protected String doInBackground(String... arg0) {
URL url = null;
InputStream is = null;
HttpURLConnection urlConn = null;
int responseCode = 0;
try {
url = new URL(arg0[0]);
urlConn = (HttpURLConnection) url.openConnection();
urlConn.setReadTimeout(10000);
urlConn.setConnectTimeout(15000);
urlConn.setRequestMethod("GET");
urlConn.connect();
responseCode = urlConn.getResponseCode();
Log.d("DataHandlerInternet:RESPONSE_CODE", "The response is: " + responseCode);
is= urlConn.getInputStream();
StringBuilder sb = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
String line = null;
while ( (line = br.readLine()) != null ) {
sb.append(line);
}
return sb.toString();
}
catch ( MalformedURLException e ) { // new URL() went wrong!
//TODO error message. URL is not correct!
e.printStackTrace();
}
catch (SocketTimeoutException e) { // Timeout while connecting or holding connection to URL.
//TODO error message. Timeout happened!
e.printStackTrace();
}
catch ( IOException e ) { // openConnection() failed!
//TODO error message. Couldn't connect to URL!
e.printStackTrace();
}
catch( Exception e ) { // Any other Exception!
e.printStackTrace();
}
finally {
try { if(is != null) { is.close(); } } catch(Exception e) {e.printStackTrace();}
try { if(urlConn != null) { urlConn.disconnect(); } } catch(Exception e) {e.printStackTrace();}
}
return null;
}
And still, after going through the while loop the return line; is completely ignored. I've checked the data in the String with the debugger and it was correct! No Errors no Exceptions.
finally will run in either case, also during normal return without exceptions. And you call .close in the finally statement clause.
So your code always returns the closed stream. Probably this is not that you intend.
Your description ("jumps to finally statement") still looks very much like a exception has been thrown by urlConn.getInputStream(). Strange you do not observe it.
I dont see why you get your null result but, one thing you are doing wrong is actually returning InputStream:
is= urlConn.getInputStream(); //-->(1)<--
return is;
you should read your stream in doInBackground (on worker thread), otherwise reading it in onPostExecute (UI Thread), will possibly cause NetworkOnMainThreadException, or at least ANR. Reading data from InputStream is still a network operation - data you download can be several MBs.
I'm trying to execute this command from the application emulator terminal (you can find it in google play) in this app i write su and press enter, so write:
screenrecord --time-limit 10 /sdcard/MyVideo.mp4
and press again enter and start the recording of the screen using the new function of android kitkat.
so, i try to execute the same code from java using this:
Process su = Runtime.getRuntime().exec("su");
Process execute = Runtime.getRuntime().exec("screenrecord --time-limit 10 /sdcard/MyVideo.mp4");
But don't work because the file is not created. obviously i'm running on a rooted device with android kitkat installed. where is the problem? how can i solve? because from terminal emulator works and in Java not?
You should grab the standard input of the su process just launched and write down the command there, otherwise you are running the commands with the current UID.
Try something like this:
try{
Process su = Runtime.getRuntime().exec("su");
DataOutputStream outputStream = new DataOutputStream(su.getOutputStream());
outputStream.writeBytes("screenrecord --time-limit 10 /sdcard/MyVideo.mp4\n");
outputStream.flush();
outputStream.writeBytes("exit\n");
outputStream.flush();
su.waitFor();
}catch(IOException e){
throw new Exception(e);
}catch(InterruptedException e){
throw new Exception(e);
}
A modification of the code by #CarloCannas:
public static void sudo(String...strings) {
try{
Process su = Runtime.getRuntime().exec("su");
DataOutputStream outputStream = new DataOutputStream(su.getOutputStream());
for (String s : strings) {
outputStream.writeBytes(s+"\n");
outputStream.flush();
}
outputStream.writeBytes("exit\n");
outputStream.flush();
try {
su.waitFor();
} catch (InterruptedException e) {
e.printStackTrace();
}
outputStream.close();
}catch(IOException e){
e.printStackTrace();
}
}
(You are welcome to find a better place for outputStream.close())
Usage example:
private static void suMkdirs(String path) {
if (!new File(path).isDirectory()) {
sudo("mkdir -p "+path);
}
}
Update:
To get the result (the output to stdout), use:
public static String sudoForResult(String...strings) {
String res = "";
DataOutputStream outputStream = null;
InputStream response = null;
try{
Process su = Runtime.getRuntime().exec("su");
outputStream = new DataOutputStream(su.getOutputStream());
response = su.getInputStream();
for (String s : strings) {
outputStream.writeBytes(s+"\n");
outputStream.flush();
}
outputStream.writeBytes("exit\n");
outputStream.flush();
try {
su.waitFor();
} catch (InterruptedException e) {
e.printStackTrace();
}
res = readFully(response);
} catch (IOException e){
e.printStackTrace();
} finally {
Closer.closeSilently(outputStream, response);
}
return res;
}
public static String readFully(InputStream is) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int length = 0;
while ((length = is.read(buffer)) != -1) {
baos.write(buffer, 0, length);
}
return baos.toString("UTF-8");
}
The utility to silently close a number of Closeables (SoŃket may be no Closeable) is:
public class Closer {
// closeAll()
public static void closeSilently(Object... xs) {
// Note: on Android API levels prior to 19 Socket does not implement Closeable
for (Object x : xs) {
if (x != null) {
try {
Log.d("closing: "+x);
if (x instanceof Closeable) {
((Closeable)x).close();
} else if (x instanceof Socket) {
((Socket)x).close();
} else if (x instanceof DatagramSocket) {
((DatagramSocket)x).close();
} else {
Log.d("cannot close: "+x);
throw new RuntimeException("cannot close "+x);
}
} catch (Throwable e) {
Log.x(e);
}
}
}
}
}
Process p;
StringBuffer output = new StringBuffer();
try {
p = Runtime.getRuntime().exec(params[0]);
BufferedReader reader = new BufferedReader(
new InputStreamReader(p.getInputStream()));
String line = "";
while ((line = reader.readLine()) != null) {
output.append(line + "\n");
p.waitFor();
}
}
catch (IOException e) {
e.printStackTrace();
} catch (InterruptedException e) {
e.printStackTrace();
}
String response = output.toString();
return response;
Late reply, but it will benefit someone. You can use the sh command in the exec() method.
Here is my example:
try {
File workingDirectory = new File(getApplicationContext().getFilesDir().getPath());
Process shProcess = Runtime.getRuntime().exec("sh", null, workingDirectory);
try{
PrintWriter outputExec = new PrintWriter(new OutputStreamWriter(shProcess.getOutputStream()));
outputExec.println("PATH=$PATH:/data/data/com.bokili.server.nginx/files;export LD_LIBRARY_PATH=/data/data/com.bokili.server.nginx/files;nginx;exit;");
outputExec.flush();
} catch(Exception ignored){ }
shProcess.waitFor();
} catch (IOException ignored) {
} catch (InterruptedException e) {
try{ Thread.currentThread().interrupt(); }catch(Exception ignored){}
} catch (Exception ignored) { }
What have I done with this?
First I call the shell, then I change (set) the necessary environments in it, and finally I start my nginx with it.
This works on unrooted devices too.
Greetings.
I'm still receiving 1st file my app generated for me.
First , I thought it's because the file exists so I wrote
File file=new File(getCacheDir(), "Competition.xls");
if (file.exists()) {file.delete(); file =new File(getCacheDir(), "Competition.xls");}
But that didn't help me-I still receive first file that was made
I'm new to working with files so I decided to copy entire method here. Sorry for a lot of text.
private void createFileTosend() {
InputStream inputStream = null;
FileOutputStream outputStream = null;
try {
File toSend=null;
try {
toSend = getFile();
} catch (WriteException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
inputStream = new FileInputStream(toSend);
outputStream = openFileOutput("Competition.xls",
Context.MODE_WORLD_READABLE | Context.MODE_APPEND);
byte[] buffer = new byte[1024];
int length = 0;
try {
while ((length = inputStream.read(buffer)) > 0){
outputStream.write(buffer, 0, length);
}
} catch (IOException ioe) {
/* ignore */
}
} catch (FileNotFoundException fnfe) {
/* ignore */
} finally {
try {
inputStream.close();
} catch (IOException ioe) {
/* ignore */
}
try {
outputStream.close();
} catch (IOException ioe) {
/* ignore */
}
}
}
public File getFile() throws IOException, WriteException{
File file=new File(getCacheDir(), "Competition.xls");
if (file.exists()) {file.delete(); file =new File(getCacheDir(), "Competition.xls");}
WritableWorkbook workbook = Workbook.createWorkbook(file);
//then goes long block with creating a .xls file which is not important
workbook.write();
workbook.close();
return file;
}
Help on understanding where the problem is
You should never have a structure like :
catch(Exception ex ) {
//ignore (or log only)
}
Exception are there to tell you something went wrong. What you do is called (in french) "eating/hiding exceptions". You are loosing this very important information that something went abnormally.
You should always either throw the exception you catch to your caller, or process it locally. At the very least, and this is a poor practice, you should log it. But doing nothing is just very wrong.
Here, put the whole try catch in a method for instance :
private void createFileTosend() throws IOException {
InputStream inputStream = null;
FileOutputStream outputStream = null;
try {
File toSend = getFile();
inputStream = new FileInputStream(toSend);
outputStream = openFileOutput("Competition.xls",
Context.MODE_WORLD_READABLE | Context.MODE_APPEND);
byte[] buffer = new byte[1024];
int length = 0;
while ((length = inputStream.read(buffer)) > 0){
outputStream.write(buffer, 0, length);
}
} finally {
try {
if( inputStream != null ) {
inputStream.close();
}
} catch (IOException ioe) {
Log.e( ioe );
}
try {
if( outputStream != null ) {
outputStream.close();
}
} catch (IOException ioe) {
Log.e( ioe );
}
}
}
And now, when you call createFileToSend, do that in a try/catch structure and toast a message, or something if you catch an exception.