Develop Reference

How to get both parts and InputStream from a request

I can't get the parts of a HTTP request and its InputStream at the same time.
If I read the InputStream, then the part will be null.
And I tried to save them, but if I get the parts, the InputStream can't be read.
public RepeatReadRequest(HttpServletRequest request) {
super(request);
try {
parts = request.getParts();
} catch (Exception e) {
}
try {
byte[] tempBuffer = new byte[bufferSize];
ServletInputStream inputStream = request.getInputStream();
int len = inputStream.read(tempBuffer);
if (len < 0) {
len = 0;
}
buffer = Arrays.copyOf(tempBuffer, len);
} catch (Exception e) {
e.printStackTrace();
}
}

Download Image from Url and covert into byte array - android

I'm receiving URL of images and other data from API and showing images into recyclerview, I want to store images in room database in a byte array format, but I'm getting an error while converting image URL to a byte array. My app is crashing at url.openstream();.
private byte[] getByteArrayImage(String imageUrl) {
URL url = null;
try {
url = new URL(imageUrl);
} catch (MalformedURLException e) {
e.printStackTrace();
}
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
try {
byte[] chunk = new byte[4096];
int bytesRead;
InputStream stream = url.openStream();
while ((bytesRead = stream.read(chunk)) > 0) {
outputStream.write(chunk, 0, bytesRead);
}
url.openStream().close();
} catch (IOException e) {
e.printStackTrace();
return null;
}
return outputStream.toByteArray();
}

There are a couple of problems with your code:
As already noted in a comment, you call openStream() twice.
If an exception occurs, close() won't be called in your code. Use try-with-resources instead.
Propagate exceptions to the caller. The caller will generally want to know the exception message.
Don't ever use printStackTrace(). This is the worst way to report errors.
After the first printStackTrace(), you continue with a null URI, which will cause a NullPointerException.
The method should be static.
Here's how I would write this:
private static byte[] getImageBytes(String imageUrl) throws IOException
{
URL url = new URL(imageUrl);
ByteArrayOutputStream output = new ByteArrayOutputStream();
try (InputStream stream = url.openStream())
{
byte[] buffer = new byte[4096];
while (true)
{
int bytesRead = stream.read(buffer);
if (bytesRead < 0) { break; }
output.write(buffer, 0, bytesRead);
}
}
return output.toByteArray();
}

I recommend below pseudo code to read data from URL:
Thread t = new Thread(new Runnable()
{
#Override
public void run()
{
try
{
URL url = new URL("you'r address");
URLConnection connection = url.openConnection();
InputStream is = connection.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
StringBuffer sb = new StringBuffer();
int r;
while((r = isr.read()) != -1)
{
sb.append(r);
}
byte buffer[] = sb.toString().getBytes();
}
catch (MalformedURLException e)
{
e.printStackTrace();
Log.i("tag" , "MalformedURLException"+e.getMessage());
}
catch (IOException e)
{
e.printStackTrace();
Log.i("tag" , "IOException"+e.getMessage());
}
}
});
t.start();

After downloading whole (84M) file from dropbox it turning into 0 bytes

I am downloading a zip file from dropbox. When it keeps downloading I measure the file size and get it is increasing its size with the Below code. It downloads whole 84M and after finishing download it turns into 0 bytes. What wrong am I actually doing?
public static void downloadDropBox(File file) {
String url = "https://www.dropbox.com/sh/jx4b2wvqg8d4ze1/AAA0J3LztkRc6FJ5tKy4dUKha?dl=1";
int bytesRead;
byte[] bytesArray = new byte[1024];
InputStream is = null;
FileOutputStream outputStream = null;
long progres = 0;
try {
URL fileUrl = new URL(url);
HttpURLConnection connection = (HttpURLConnection)fileUrl.openConnection();
connection.connect();
is = connection.getInputStream();
outputStream = new FileOutputStream(file);
while ((bytesRead = is.read(bytesArray, 0, 1024)) != -1) {
outputStream.write(bytesArray, 0, bytesRead);
}
}
} catch (Exception e) {
e.printStackTrace();
}
finally {
if (is != null) {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (outputStream != null) {
try {
outputStream.flush();
outputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
During download file:
After Finishing download file:

Google Cloud Storage createOrReplace file is broken (different size, ...)

I tried to upload a stream (restlet memoryfile) to gcs. But the file has another filesize and is a little different so that the file is marked as "broken".
I tried is local and on google app engine. While debugging to this part the stream looks good in size InputStream inputStream = item.getInputStream();
But the result in the store isn't that size. There are 4 Bits at the beginning: ’[NUL][ENQ]
Where are they from?
List<FileItem> items;
try {
MemoryFileItemFactory factory = new MemoryFileItemFactory();
RestletFileUpload restletFileUpload = new RestletFileUpload(factory);
items = restletFileUpload.parseRequest(req);
//items = restletFileUpload.parseRepresentation(entity);
for (FileItem item : items) {
if (!item.isFormField()) {
MediaType type = MediaType.valueOf(item.getContentType());
GcsFileOptions options = new GcsFileOptions.Builder().mimeType(type.getName()).acl("public-read").build();
GcsOutputChannel outputChannel = gcsService.createOrReplace(fileName, options);
ObjectOutputStream oout = new ObjectOutputStream(Channels.newOutputStream(outputChannel));
InputStream inputStream = item.getInputStream();
copy(inputStream, oout);
//oout.close();
}
}
} catch (FileUploadException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
private void copy(InputStream input, OutputStream output) throws IOException {
try {
byte[] buffer = new byte[BUFFER_SIZE];
int bytesRead = input.read(buffer);
while (bytesRead != -1) {
output.write(buffer, 0, bytesRead);
bytesRead = input.read(buffer);
}
} finally {
input.close();
output.close();
}
}
private final GcsService gcsService = GcsServiceFactory.createGcsService(new RetryParams.Builder()
.initialRetryDelayMillis(10)
.retryMaxAttempts(10)
.totalRetryPeriodMillis(15000)
.build());

Remove the finally close statements from the copy-function and close the GcsOutputChannel instead. Further you don't need to do this: ObjectOutputStream oout = new ObjectOutputStream(Channels.newOutputStream(outputChannel));
Maybe that adds the extra-bits
Something like that:
GcsOutputChannel outputChannel = gcsService.createOrReplace(fileName, options);
InputStream inputStream = item.getInputStream();
try {
copy(inputStream, Channels.newOutputStream(outputChannel));
} finally {
outputChannel.close();
inputStream.close();
}
private void copy(InputStream input, OutputStream output) throws IOException {
byte[] buffer = new byte[BUFFER_SIZE];
int bytesRead = input.read(buffer);
while (bytesRead != -1) {
output.write(buffer, 0, bytesRead);
bytesRead = input.read(buffer);
}
}

GZIP compression to a byte array

I am trying to write a class that can compress data. The below code fails (no exception is thrown, but the target .gz file is empty.)
Besides: I don't want to generate the .gz file directly like it is done in all examples. I only want to get the compressed
data, so that I can e.g. encrypt it before writting the data to a file.
If I write directly to a file everything works fine:
import java.io.*;
import java.util.zip.*;
import java.nio.charset.*;
public class Zipper
{
public static void main(String[] args)
{
byte[] dataToCompress = "This is the test data."
.getBytes(StandardCharsets.ISO_8859_1);
GZIPOutputStream zipStream = null;
FileOutputStream fileStream = null;
try
{
fileStream = new FileOutputStream("C:/Users/UserName/Desktop/zip_file.gz");
zipStream = new GZIPOutputStream(fileStream);
zipStream.write(dataToCompress);
fileStream.write(compressedData);
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
try{ zipStream.close(); }
catch(Exception e){ }
try{ fileStream.close(); }
catch(Exception e){ }
}
}
}
But, if I want to 'bypass' it to the byte array stream it does not produce a single byte - compressedData is always empty.
import java.io.*;
import java.util.zip.*;
import java.nio.charset.*;
public class Zipper
{
public static void main(String[] args)
{
byte[] dataToCompress = "This is the test data."
.getBytes(StandardCharsets.ISO_8859_1);
byte[] compressedData = null;
GZIPOutputStream zipStream = null;
ByteArrayOutputStream byteStream = null;
FileOutputStream fileStream = null;
try
{
byteStream = new ByteArrayOutputStream(dataToCompress.length);
zipStream = new GZIPOutputStream(byteStream);
zipStream.write(dataToCompress);
compressedData = byteStream.toByteArray();
fileStream = new FileOutputStream("C:/Users/UserName/Desktop/zip_file.gz");
fileStream.write(compressedData);
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
try{ zipStream.close(); }
catch(Exception e){ }
try{ byteStream.close(); }
catch(Exception e){ }
try{ fileStream.close(); }
catch(Exception e){ }
}
}
}

The problem is that you are not closing the GZIPOutputStream. Until you close it the output will be incomplete.
You just need to close it before reading the byte array. You need to reorder the finally blocks to achieve this.
import java.io.*;
import java.util.zip.*;
import java.nio.charset.*;
public class Zipper
{
public static void main(String[] args)
{
byte[] dataToCompress = "This is the test data."
.getBytes(StandardCharsets.ISO_8859_1);
try
{
ByteArrayOutputStream byteStream =
new ByteArrayOutputStream(dataToCompress.length);
try
{
GZIPOutputStream zipStream =
new GZIPOutputStream(byteStream);
try
{
zipStream.write(dataToCompress);
}
finally
{
zipStream.close();
}
}
finally
{
byteStream.close();
}
byte[] compressedData = byteStream.toByteArray();
FileOutputStream fileStream =
new FileOutputStream("C:/Users/UserName/Desktop/zip_file.gz");
try
{
fileStream.write(compressedData);
}
finally
{
try{ fileStream.close(); }
catch(Exception e){ /* We should probably delete the file now? */ }
}
}
catch(Exception e)
{
e.printStackTrace();
}
}
}
I do not recommend inititalizing the stream variables to null, because it means your finally block can also throw a NullPointerException.
Also note that you can declare main to throw IOException (then you would not need the outermost try statement.)
There is little point in swallowing exceptions from zipStream.close();, because if it throws an exception you will not have a valid .gz file (so you should not proceed to write it.)
Also I would not swallow exceptions from byteStream.close(); but for a different reason - they should never be thrown (i.e. there is a bug in your JRE and you would want to know about that.)

I've improved JITHINRAJ's code - used try-with-resources:
private static byte[] gzipCompress(byte[] uncompressedData) {
byte[] result = new byte[]{};
try (ByteArrayOutputStream bos = new ByteArrayOutputStream(uncompressedData.length);
GZIPOutputStream gzipOS = new GZIPOutputStream(bos)) {
gzipOS.write(uncompressedData);
// You need to close it before using bos
gzipOS.close();
result = bos.toByteArray();
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
private static byte[] gzipUncompress(byte[] compressedData) {
byte[] result = new byte[]{};
try (ByteArrayInputStream bis = new ByteArrayInputStream(compressedData);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
GZIPInputStream gzipIS = new GZIPInputStream(bis)) {
byte[] buffer = new byte[1024];
int len;
while ((len = gzipIS.read(buffer)) != -1) {
bos.write(buffer, 0, len);
}
result = bos.toByteArray();
} catch (IOException e) {
e.printStackTrace();
}
return result;
}

If you are still looking an answer you can use the below code to get the compressed byte[] using deflater and decompress it using inflater.
public static void main(String[] args) {
//Some string for testing
String sr = new String("fsdfesfsfdddddddsfdsfssdfdsfdsfdsfdsfdsdfggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggghghghghggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggfsdfesfsfdddddddsfdsfssdfdsfdsfdsfdsfdsdfggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggghghghghggggggggggggggggggggggggggggggggggggggggg");
byte[] data = sr.getBytes();
System.out.println("src size "+data.length);
try {
compress(data);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public static byte[] compress(byte[] data) throws IOException {
Deflater deflater = new Deflater();
deflater.setInput(data);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream(data.length);
deflater.finish();
byte[] buffer = new byte[1024];
while (!deflater.finished()) {
int count = deflater.deflate(buffer);
outputStream.write(buffer, 0, count);
}
outputStream.close();
byte[] output = outputStream.toByteArray();
System.out.println("Original: " + data.length );
System.out.println("Compressed: " + output.length );
return output;
}

To compress
private static byte[] compress(byte[] uncompressedData) {
ByteArrayOutputStream bos = null;
GZIPOutputStream gzipOS = null;
try {
bos = new ByteArrayOutputStream(uncompressedData.length);
gzipOS = new GZIPOutputStream(bos);
gzipOS.write(uncompressedData);
gzipOS.close();
return bos.toByteArray();
} catch (IOException e) {
e.printStackTrace();
}
finally {
try {
assert gzipOS != null;
gzipOS.close();
bos.close();
}
catch (Exception ignored) {
}
}
return new byte[]{};
}
To uncompress
private byte[] uncompress(byte[] compressedData) {
ByteArrayInputStream bis = null;
ByteArrayOutputStream bos = null;
GZIPInputStream gzipIS = null;
try {
bis = new ByteArrayInputStream(compressedData);
bos = new ByteArrayOutputStream();
gzipIS = new GZIPInputStream(bis);
byte[] buffer = new byte[1024];
int len;
while((len = gzipIS.read(buffer)) != -1){
bos.write(buffer, 0, len);
}
return bos.toByteArray();
} catch (IOException e) {
e.printStackTrace();
}
finally {
try {
assert gzipIS != null;
gzipIS.close();
bos.close();
bis.close();
}
catch (Exception e) {
e.printStackTrace();
}
}
return new byte[]{};
}

You can use the below function, it is tested and working fine.
In general, your code has serious problem of ignoring the exceptions! returning null or simply not printing anything in the catch block will make it very difficult to debug
You do not have to write the zip output to a file if you want to process it further (e.g. encrypt it), you can easily modify the code to write the output to in-memory stream
public static String zip(File inFile, File zipFile) throws IOException {
FileInputStream fis = new FileInputStream(inFile);
FileOutputStream fos = new FileOutputStream(zipFile);
ZipOutputStream zout = new ZipOutputStream(fos);
try {
zout.putNextEntry(new ZipEntry(inFile.getName()));
byte[] buffer = new byte[BUFFER_SIZE];
int len;
while ((len = fis.read(buffer)) > 0) {
zout.write(buffer, 0, len);
}
zout.closeEntry();
} catch (Exception ex) {
ex.printStackTrace();
return null;
} finally {
try{zout.close();}catch(Exception ex){ex.printStackTrace();}
try{fis.close();}catch(Exception ex){ex.printStackTrace();}
}
return zipFile.getAbsolutePath();
}

Most of the examples have wrong exception handling.
public static byte[] gzipBytes(byte[] payload) {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try (GZIPOutputStream gzip = new GZIPOutputStream(baos)) {
gzip.write(payload);
} catch (IOException e) {
throw new UncheckedIOException(e);
}
// note: toByteArray should be called after try-with-resources, not inside
return baos.toByteArray();
}
public static byte[] gunzipBytes(byte[] gzPayload) {
ByteArrayInputStream bais = new ByteArrayInputStream(gzPayload);
try (GZIPInputStream gzip = new GZIPInputStream(bais)) {
// java 9+ required for this method
return gzip.readAllBytes();
} catch (IOException e) {
throw new UncheckedIOException("Error while unpacking gzip content", e);
}
}

Try with this code..
try {
String inputFileName = "test.txt"; //may use your file_Path
String zipFileName = "compressed.zip";
//Create input and output streams
FileInputStream inStream = new FileInputStream(inputFileName);
ZipOutputStream outStream = new ZipOutputStream(new FileOutputStream(zipFileName));
// Add a zip entry to the output stream
outStream.putNextEntry(new ZipEntry(inputFileName));
byte[] buffer = new byte[1024];
int bytesRead;
//Each chunk of data read from the input stream
//is written to the output stream
while ((bytesRead = inStream.read(buffer)) > 0) {
outStream.write(buffer, 0, bytesRead);
}
//Close zip entry and file streams
outStream.closeEntry();
outStream.close();
inStream.close();
} catch (IOException ex) {
ex.printStackTrace();
}
Also may be helpful this one..
http://www.java-samples.com/java/zip_files_in_a_folder_using_java.htm