Develop Reference

How to convert base64 to different kind of files ( doc , pdf , word ..etc ) ?

I am working on project where I have to download attachments that i receive from server. I have to exploit base64 data and convert it to the appropriate type and download it. It works for me perfectly with images ( base 64 => bytes => bitmap ) but I find troubles with other types ( txt , pdf ..etc )

try this
try {
File sdcard = Environment.getExternalStorageDirectory();
File file = new File(sdcard,"test.pdf");
File new_file_name = new File(sdcard,"new_file.pdf");
byte[] input_file = IOUtil.readFile(file);
byte[] encodedBytes = Base64.encode(input_file,URL_SAFE);
String encodedString = new String(encodedBytes);
byte[] decodedBytes = Base64.decode(encodedString.getBytes(),URL_SAFE);
FileOutputStream fos = new FileOutputStream(new_file_name);
fos.write(decodedBytes);
fos.flush();
fos.close();
}catch (Exception e)
{
Log.e("ERROR",e.toString());
}
And IOUtil class
public class IOUtil {
public static byte[] readFile(String file) throws IOException {
return readFile(new File(file));
}
public static byte[] readFile(File file) throws IOException {
// Open file
RandomAccessFile f = new RandomAccessFile(file, "r");
try {
// Get and check length
long longlength = f.length();
int length = (int) longlength;
if (length != longlength)
throw new IOException("File size >= 2 GB");
// Read file and return data
byte[] data = new byte[length];
f.readFully(data);
return data;
} finally {
f.close();
}
}
}
this code contain both encode and decode parts

How to create a ZIP InputStream in Android without creating a ZIP file first?

I use NanoHTTPD as web server in my Android APP, I hope to compress some files and create a InputStream in server side, and I download the InputStream in client side using Code A.
I have read Code B at How to zip and unzip the files?, but how to create a ZIP InputStream in Android without creating a ZIP file first?
BTW, I don't think Code C is good way, because it make ZIP file first, then convert ZIP file to FileInputStream , I hope to create a ZIP InputStream directly!
Code A
private Response ActionDownloadSingleFile(InputStream fis) {
Response response = null;
response = newChunkedResponse(Response.Status.OK, "application/octet-stream",fis);
response.addHeader("Content-Disposition", "attachment; filename="+"my.zip");
return response;
}
Code B
public static void zip(String[] files, String zipFile) throws IOException {
BufferedInputStream origin = null;
ZipOutputStream out = new ZipOutputStream(new BufferedOutputStream(new FileOutputStream(zipFile)));
try {
byte data[] = new byte[BUFFER_SIZE];
for (int i = 0; i < files.length; i++) {
FileInputStream fi = new FileInputStream(files[i]);
origin = new BufferedInputStream(fi, BUFFER_SIZE);
try {
ZipEntry entry = new ZipEntry(files[i].substring(files[i].lastIndexOf("/") + 1));
out.putNextEntry(entry);
int count;
while ((count = origin.read(data, 0, BUFFER_SIZE)) != -1) {
out.write(data, 0, count);
}
}
finally {
origin.close();
}
}
}
finally {
out.close();
}
}
Code C
File file= new File("my.zip");
FileInputStream fis = null;
try
{
fis = new FileInputStream(file);
} catch (FileNotFoundException ex)
{
}

ZipInputStream as per the documentation ZipInputStream
ZipInputStream is an input stream filter for reading files in the ZIP file format. Includes support for both compressed and uncompressed entries.
Earlier I answered to this question in a way that it is not possible using ZipInputStream. I am Sorry.
But after investing some time I found that it is possible as per the below code
It is very much obvious that since you are sending files in zip format
over the network.
//Create proper background thread pool. Not best but just for solution
new Thread(new Runnable() {
#Override
public void run() {
// Moves the current Thread into the background
android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_BACKGROUND);
HttpURLConnection httpURLConnection = null;
byte[] buffer = new byte[2048];
try {
//Your http connection
httpURLConnection = (HttpURLConnection) new URL("https://s3-ap-southeast-1.amazonaws.com/uploads-ap.hipchat.com/107225/1251522/SFSCjI8ZRB7FjV9/zvsd.zip").openConnection();
//Change below path to Environment.getExternalStorageDirectory() or something of your
// own by creating storage utils
File outputFilePath = new File ("/mnt/sdcard/Android/data/somedirectory/");
ZipInputStream zipInputStream = new ZipInputStream(new BufferedInputStream(httpURLConnection.getInputStream()));
ZipEntry zipEntry = zipInputStream.getNextEntry();
int readLength;
while(zipEntry != null){
File newFile = new File(outputFilePath, zipEntry.getName());
if (!zipEntry.isDirectory()) {
FileOutputStream fos = new FileOutputStream(newFile);
while ((readLength = zipInputStream.read(buffer)) > 0) {
fos.write(buffer, 0, readLength);
}
fos.close();
} else {
newFile.mkdirs();
}
Log.i("zip file path = ", newFile.getPath());
zipInputStream.closeEntry();
zipEntry = zipInputStream.getNextEntry();
}
// Close Stream and disconnect HTTP connection. Move to finally
zipInputStream.closeEntry();
zipInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}finally {
// Close Stream and disconnect HTTP connection.
if (httpURLConnection != null) {
httpURLConnection.disconnect();
}
}
}
}).start();

java servlet response returning data

Servlet uses a javax.servlet.http.HttpServletResponse object to return data to the client request. How do you use it to return the following types of data? a. Text data b. Binary data

Change the content type of the response and the content itself of the response.
For text data:
response.setContentType("text/plain");
response.getWriter().write("Hello world plain text response.");
response.getWriter().close();
For binary data ,usually for file downloading (code adapted from here):
response.setContentType("application/octet-stream");
BufferedInputStream input = null;
BufferedOutputStream output = null;
try {
//file is a File object or a String containing the name of the file to download
input = new BufferedInputStream(new FileInputStream(file));
output = new BufferedOutputStream(response.getOutputStream());
//read the data from the file in chunks
byte[] buffer = new byte[1024 * 4];
for (int length = 0; (length = input.read(buffer)) > 0;) {
//copy the data from the file to the response in chunks
output.write(buffer, 0, length);
}
} finally {
//close resources
if (output != null) try { output.close(); } catch (IOException ignore) {}
if (input != null) try { input.close(); } catch (IOException ignore) {}
}

OutOfMemory when creating Base64 string in java?

I used ostermillerutils library to create base64 string but I get OutOfMemory error if the image is heavy. If the image I try to convert is a simple image, the code is working fine.
public String createBase64String(InputStream in) {
//collect = new ByteArrayOutputStream();
ByteArrayOutputStream bos = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
try {
for(int readNum; (readNum = in.read(buf)) != -1; ) {
bos.write(buf, 0, readNum);
}
}
catch (IOException ex) {
Logger.getInstance().debug("XML createBase64String: IOException");
return null;
}
finally {
if (in != null) {
try {
in.close();
}
catch (IOException ex) {
;
}
}
}
byte[] ba = bos.toByteArray();
String coded = Base64.encodeToString(ba);
return coded;
}
I also tried doing this but the base64 was incorrect when I tried to decode it.
public void createBase64String(InputStream in) throws IOException {
//collect = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
int readNum = 0;
try {
while((readNum = in.read(buf)) != -1)
{
smtp.addBase64(Base64.encodeBase64String(buf));
}
}
catch (IOException ex) {
Logger.getInstance().debug("XML createBase64String: IOException");
}
finally {
if (in != null) {
in.close();
}
}
}
Please suggest solutions for JDK 1.4 and also for later versions of Java.

If you like to write the encoded content straight into a file then use the following code
public void encode(File file, OutputStream base64OutputStream) {
InputStream is = new FileInputStream(file);
OutputStream out = new Base64OutputStream(base64OutputStream)
IOUtils.copy(is, out);
is.close();
out.close();
}
IOUtils class from Apache Commons IO.
EDIT
Since you want to do it using BufferedWriter, use it as follows
OutputStream out = Base64OutputStream(smtpSocket.getOutputStream());
BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(out));
IOUtils.copy(is, bw);

It sounds like the problem is that you're having to manipulate too much data in memory when you read the entire image. One fix would be to increase the Java heap size until you have enough memory, but that would just be avoiding the problem rather than solving it.
A better option would be to look at a streaming implementation of a Base64 encoder. This would mean you're only working on a subset of the image at any time. I believe that Base64OutputStream from Apache Commons would do the job for you.

I've fixed my problem by using javabase64-1.3.1.jar library.
OutputStream fos2 = FileUtil.getOutputStream(base64FileName, FileUtil.HDD);
InputStream in2 = FileUtil.getInputStream(fileName, FileUtil.HDD);
Base64.encode(in2, fos2);
in2.close();
fos2.close();
I stored the base64 string to a text file first.
public void createBase64String(InputStream in) throws IOException {
baos = new ByteArrayOutputStream();
byte[] buf = new byte[BUFFER_SIZE];
int readNum = 0;
smtp.addBase64("\t\t");
try {
while ((readNum = in.read(buf)) >= 0) {
baos.write(buf, 0, readNum);
smtp.addBase64(baos.toString());
baos.reset();
}
}
catch (IOException ex) {
LogUtil.error("Sending of Base64 String to SMTP: IOException: " + ex);
}
finally {
if (in != null) {
in.close();
baos.close();
}
}
baos = null;
buf = null;
}
then send each line to smtp's socket outputstream.

From Java 8 onwards, there is a simple way to implement base64 encoding in an output stream with one line of code and no external dependencies:
import java.util.Base64;
OutputStream os = ...
OutputStream base64 = Base64.getEncoder().wrap(os);
Base64 also provides other flavors of base64 encoder; see javadocs:
Base64
Base64.Encoder.wrap

Decompressed video file is not working in Java

Basically i compress video using the customized compressor class in Java. I have assembled my complete code snippets here. My actually problem is, generated video [ A.mp4] from the decompressed byte array is not running. I actually i got this compressor class code over the internet. As i new to Java platform, i am struggling to resolve this problem. Could you please any one help me on this.?
public class CompressionTest
{
public static void main(String[] args)
{
Compressor compressor = new Compressor();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
FileInputStream fis=null;
File file=null;
try
{
URL uri=CompressionTest.class.getResource("/Files/Video.mp4");
file=new File(uri.getPath());
fis = new FileInputStream(file);
}
catch ( FileNotFoundException fnfe )
{
System.out.println( "Unable to open input file");
}
try
{
byte[] videoBytes = getBytesFromFile(file);
System.out.println("CompressionVideoToCompress is: '" +videoBytes + "'");
byte[] bytesCompressed = compressor.compress(videoBytes);
System.out.println("bytesCompressed is: '" +bytesCompressed+ "'");
byte[] bytesDecompressed=compressor.decompress(bytesCompressed);
System.out.println("bytesDecompressed is: '" +bytesDecompressed+ "'");
FileOutputStream out = new FileOutputStream("A.mp4");
out.write(bytesDecompressed,0,bytesDecompressed.length-1);
out.close();
}
catch (IOException e)
{
// TODO Auto-generated catch block
System.out.println("bytesCompressed is: '");
}
}
public static byte[] getBytesFromFile(File file) throws IOException
{
InputStream is = new FileInputStream(file);
// Get the size of the file
long length = file.length();
// You cannot create an array using a long type.
// It needs to be an int type.
// Before converting to an int type, check
// to ensure that file is not larger than Integer.MAX_VALUE.
if (length > Integer.MAX_VALUE) {
// File is too large
}
// Create the byte array to hold the data
byte[] bytes = new byte[1064];
// Read in the bytes
int offset = 0;
int numRead = 0;
while (offset < bytes.length
&& (numRead=is.read(bytes, offset, bytes.length-offset)) >= 0)
{
offset += numRead;
}
// Ensure all the bytes have been read in
if (offset < bytes.length) {
throw new IOException("Could not completely read file "+file.getName());
}
// Close the input stream and return bytes
is.close();
return bytes;
}
}
class Compressor
{
public Compressor()
{}
public byte[] compress(byte[] bytesToCompress)
{
Deflater deflater = new Deflater();
deflater.setInput(bytesToCompress);
deflater.finish();
byte[] bytesCompressed = new byte[Short.MAX_VALUE];
int numberOfBytesAfterCompression = deflater.deflate(bytesCompressed);
byte[] returnValues = new byte[numberOfBytesAfterCompression];
System.arraycopy
(
bytesCompressed,
0,
returnValues,
0,
numberOfBytesAfterCompression
);
return returnValues;
}
public byte[] decompress(byte[] bytesToDecompress)
{
Inflater inflater = new Inflater();
int numberOfBytesToDecompress = bytesToDecompress.length;
inflater.setInput
(
bytesToDecompress,
0,
numberOfBytesToDecompress
);
int compressionFactorMaxLikely = 3;
int bufferSizeInBytes =
numberOfBytesToDecompress
* compressionFactorMaxLikely;
byte[] bytesDecompressed = new byte[bufferSizeInBytes];
byte[] returnValues = null;
try
{
int numberOfBytesAfterDecompression = inflater.inflate(bytesDecompressed);
returnValues = new byte[numberOfBytesAfterDecompression];
System.arraycopy
(
bytesDecompressed,
0,
returnValues,
0,
numberOfBytesAfterDecompression
);
}
catch (DataFormatException dfe)
{
dfe.printStackTrace();
}
inflater.end();
return returnValues;
}
}

I've tested your code by compressing and decompressing a simple TXT file. The code is broken, since the compressed file, when uncompressed, is different from the original one.
Take for granted that the code is broken at least in the getBytesFromFile function. Its logic is tricky and troublesome, since it only allows files up to length 1064 and the check (throwing IOException when a longer file is read) does not work at all. The file gets read only partially and no exception is thrown.
What you are trying to achieve (file compression/decompression) can be done this way. I've tested it and it works, you just need this library.
import java.io.*;
import java.util.zip.*;
import org.apache.commons.io.IOUtils; // <-- get this from http://commons.apache.org/io/index.html
public class CompressionTest2 {
public static void main(String[] args) throws IOException {
File input = new File("input.txt");
File output = new File("output.bin");
Compression.compress(input, output);
File input2 = new File("input2.txt");
Compression.decompress(output, input2);
// At this point, input.txt and input2.txt should be equal
}
}
class Compression {
public static void compress(File input, File output) throws IOException {
FileInputStream fis = new FileInputStream(input);
FileOutputStream fos = new FileOutputStream(output);
GZIPOutputStream gzipStream = new GZIPOutputStream(fos);
IOUtils.copy(fis, gzipStream);
gzipStream.close();
fis.close();
fos.close();
}
public static void decompress(File input, File output) throws IOException {
FileInputStream fis = new FileInputStream(input);
FileOutputStream fos = new FileOutputStream(output);
GZIPInputStream gzipStream = new GZIPInputStream(fis);
IOUtils.copy(gzipStream, fos);
gzipStream.close();
fis.close();
fos.close();
}
}
This code doesn't come from "credible and/or official sources" but at least it works. :)
Moreover, in order to get more answers, adjust the title stating your real problem: your compressed files don't decompress the right way. There is no 'video' stuff here. Moreover, zipping a .mp4 file is no achievement (compression ratio will likely be around 99.99%).

Two tips:
1) Replace getBytesFromFile with a well known API call, either using Apache commons (IOUtils) or java 7 now provides such a method, too.
2) Test compress and decompress by writing a Junit test:
Create a random huge byte array, write it out, read it back and compare it with the created one.