How can I read a short array from a file e.g. audio or video file? And how can I write it back to the file?
I really doubt if SHORT if possible. Nevertheless, you can check out Apache Commons File Utils for reading file as byte[] and vice verse.
public static byte[] readFileToByteArray(File file) throws IOException
This is better example:
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
/**
Converting binary data into different forms.
<P>Reads binary data into memory, and writes it back out.
(If your're actually copying a file, there are better ways to do this.)
<P>Buffering is used when reading and writing files, to minimize the number
of interactions with the disk.
*/
public final class BytesStreamsAndFiles {
/** Change these settings before running this class. */
private static final String INPUT_FILE_NAME = "C:\\TEMP\\cottage.jpg";
private static final String OUTPUT_FILE_NAME = "C:\\TEMP\\cottage_copy.jpg";
/** Run the example. */
public static void main(String... aArgs) {
BytesStreamsAndFiles test = new BytesStreamsAndFiles();
//read in the bytes
byte[] fileContents = test.read(INPUT_FILE_NAME);
//test.readAlternateImpl(INPUT_FILE_NAME);
//write it back out to a different file name
test.write(fileContents, OUTPUT_FILE_NAME);
}
/** Read the given binary file, and return its contents as a byte array.*/
byte[] read(String aInputFileName){
log("Reading in binary file named : " + aInputFileName);
File file = new File(aInputFileName);
log("File size: " + file.length());
byte[] result = new byte[(int)file.length()];
try {
InputStream input = null;
try {
int totalBytesRead = 0;
input = new BufferedInputStream(new FileInputStream(file));
while(totalBytesRead < result.length){
int bytesRemaining = result.length - totalBytesRead;
//input.read() returns -1, 0, or more :
int bytesRead = input.read(result, totalBytesRead, bytesRemaining);
if (bytesRead > 0){
totalBytesRead = totalBytesRead + bytesRead;
}
}
/*
the above style is a bit tricky: it places bytes into the 'result' array;
'result' is an output parameter;
the while loop usually has a single iteration only.
*/
log("Num bytes read: " + totalBytesRead);
}
finally {
log("Closing input stream.");
input.close();
}
}
catch (FileNotFoundException ex) {
log("File not found.");
}
catch (IOException ex) {
log(ex);
}
return result;
}
/**
Write a byte array to the given file.
Writing binary data is significantly simpler than reading it.
*/
void write(byte[] aInput, String aOutputFileName){
log("Writing binary file...");
try {
OutputStream output = null;
try {
output = new BufferedOutputStream(new FileOutputStream(aOutputFileName));
output.write(aInput);
}
finally {
output.close();
}
}
catch(FileNotFoundException ex){
log("File not found.");
}
catch(IOException ex){
log(ex);
}
}
/** Read the given binary file, and return its contents as a byte array.*/
byte[] readAlternateImpl(String aInputFileName){
log("Reading in binary file named : " + aInputFileName);
File file = new File(aInputFileName);
log("File size: " + file.length());
byte[] result = null;
try {
InputStream input = new BufferedInputStream(new FileInputStream(file));
result = readAndClose(input);
}
catch (FileNotFoundException ex){
log(ex);
}
return result;
}
/**
Read an input stream, and return it as a byte array.
Sometimes the source of bytes is an input stream instead of a file.
This implementation closes aInput after it's read.
*/
byte[] readAndClose(InputStream aInput){
//carries the data from input to output :
byte[] bucket = new byte[32*1024];
ByteArrayOutputStream result = null;
try {
try {
//Use buffering? No. Buffering avoids costly access to disk or network;
//buffering to an in-memory stream makes no sense.
result = new ByteArrayOutputStream(bucket.length);
int bytesRead = 0;
while(bytesRead != -1){
//aInput.read() returns -1, 0, or more :
bytesRead = aInput.read(bucket);
if(bytesRead > 0){
result.write(bucket, 0, bytesRead);
}
}
}
finally {
aInput.close();
//result.close(); this is a no-operation for ByteArrayOutputStream
}
}
catch (IOException ex){
log(ex);
}
return result.toByteArray();
}
private static void log(Object aThing){
System.out.println(String.valueOf(aThing));
}
}
for more detail go to : Reading and writing binary files
The snippet below reads a file using FileInputStream, and writes the file to the given path using FileOutputStream.
Java Code:
byte[] fileBArray = new byte[(int)file.length()];
FileInputStream fis = new FileInputStream(file);
fis.read(fileBArray);
FileOutputStream fos = new FileOutputStream("C:\\abc.jpg");
fos.write(fileBArray);
Related
I've found many ways of converting a file to a byte array and writing byte array to a file on storage.
What I want is to convert java.io.File to a byte array and then convert a byte array back to a java.io.File.
I don't want to write it out to storage like the following:
//convert array of bytes into file
FileOutputStream fileOuputStream = new FileOutputStream("C:\\testing2.txt");
fileOuputStream.write(bFile);
fileOuputStream.close();
I want to somehow do the following:
File myFile = ConvertfromByteArray(bytes);
Otherwise Try this :
Converting File To Bytes
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class Temp {
public static void main(String[] args) {
File file = new File("c:/EventItemBroker.java");
byte[] b = new byte[(int) file.length()];
try {
FileInputStream fileInputStream = new FileInputStream(file);
fileInputStream.read(b);
for (int i = 0; i < b.length; i++) {
System.out.print((char)b[i]);
}
} catch (FileNotFoundException e) {
System.out.println("File Not Found.");
e.printStackTrace();
}
catch (IOException e1) {
System.out.println("Error Reading The File.");
e1.printStackTrace();
}
}
}
Converting Bytes to File
public class WriteByteArrayToFile {
public static void main(String[] args) {
String strFilePath = "Your path";
try {
FileOutputStream fos = new FileOutputStream(strFilePath);
String strContent = "Write File using Java ";
fos.write(strContent.getBytes());
fos.close();
}
catch(FileNotFoundException ex) {
System.out.println("FileNotFoundException : " + ex);
}
catch(IOException ioe) {
System.out.println("IOException : " + ioe);
}
}
}
I think you misunderstood what the java.io.File class really represents. It is just a representation of the file on your system, i.e. its name, its path etc.
Did you even look at the Javadoc for the java.io.File class? Have a look here
If you check the fields it has or the methods or constructor arguments, you immediately get the hint that all it is, is a representation of the URL/path.
Oracle provides quite an extensive tutorial in their Java File I/O tutorial, with the latest NIO.2 functionality too.
With NIO.2 you can read it in one line using java.nio.file.Files.readAllBytes().
Similarly you can use java.nio.file.Files.write() to write all bytes in your byte array.
UPDATE
Since the question is tagged Android, the more conventional way is to wrap the FileInputStream in a BufferedInputStream and then wrap that in a ByteArrayInputStream.
That will allow you to read the contents in a byte[]. Similarly the counterparts to them exist for the OutputStream.
You can't do this. A File is just an abstract way to refer to a file in the file system. It doesn't contain any of the file contents itself.
If you're trying to create an in-memory file that can be referred to using a File object, you aren't going to be able to do that, either, as explained in this thread, this thread, and many other places..
Apache FileUtil gives very handy methods to do the conversion
try {
File file = new File(imagefilePath);
byte[] byteArray = new byte[file.length()]();
byteArray = FileUtils.readFileToByteArray(file);
}catch(Exception e){
e.printStackTrace();
}
There is no such functionality but you can use a temporary file by File.createTempFile().
File temp = File.createTempFile(prefix, suffix);
// tell system to delete it when vm terminates.
temp.deleteOnExit();
You cannot do it for File, which is primarily an intelligent file path. Can you refactor your code so that it declares the variables, and passes around arguments, with type OutputStream instead of FileOutputStream? If so, see classes java.io.ByteArrayOutputStream and java.io.ByteArrayInputStream
OutputStream outStream = new ByteArrayOutputStream();
outStream.write(whatever);
outStream.close();
byte[] data = outStream.toByteArray();
InputStream inStream = new ByteArrayInputStream(data);
...
1- Traditional way
The traditional conversion way is through using read() method of InputStream as the following:
public static byte[] convertUsingTraditionalWay(File file)
{
byte[] fileBytes = new byte[(int) file.length()];
try(FileInputStream inputStream = new FileInputStream(file))
{
inputStream.read(fileBytes);
}
catch (Exception ex)
{
ex.printStackTrace();
}
return fileBytes;
}
2- Java NIO
With Java 7, you can do the conversion using Files utility class of nio package:
public static byte[] convertUsingJavaNIO(File file)
{
byte[] fileBytes = null;
try
{
fileBytes = Files.readAllBytes(file.toPath());
}
catch (Exception ex)
{
ex.printStackTrace();
}
return fileBytes;
}
3- Apache Commons IO
Besides JDK, you can do the conversion using Apache Commons IO library in 2 ways:
3.1. IOUtils.toByteArray()
public static byte[] convertUsingIOUtils(File file)
{
byte[] fileBytes = null;
try(FileInputStream inputStream = new FileInputStream(file))
{
fileBytes = IOUtils.toByteArray(inputStream);
}
catch (Exception ex)
{
ex.printStackTrace();
}
return fileBytes;
}
3.2. FileUtils.readFileToByteArray()
public static byte[] convertUsingFileUtils(File file)
{
byte[] fileBytes = null;
try
{
fileBytes = FileUtils.readFileToByteArray(file);
}
catch(Exception ex)
{
ex.printStackTrace();
}
return fileBytes;
}
Server side
#RequestMapping("/download")
public byte[] download() throws Exception {
File f = new File("C:\\WorkSpace\\Text\\myDoc.txt");
byte[] byteArray = new byte[(int) f.length()];
byteArray = FileUtils.readFileToByteArray(f);
return byteArray;
}
Client side
private ResponseEntity<byte[]> getDownload(){
URI end = URI.create(your url which server has exposed i.e. bla
bla/download);
return rest.getForEntity(end,byte[].class);
}
public static void main(String[] args) throws Exception {
byte[] byteArray = new TestClient().getDownload().getBody();
FileOutputStream fos = new
FileOutputStream("C:\\WorkSpace\\testClient\\abc.txt");
fos.write(byteArray);
fos.close();
System.out.println("file written successfully..");
}
//The file that you wanna convert into byte[]
File file=new File("/storage/0CE2-EA3D/DCIM/Camera/VID_20190822_205931.mp4");
FileInputStream fileInputStream=new FileInputStream(file);
byte[] data=new byte[(int) file.length()];
BufferedInputStream bufferedInputStream=new BufferedInputStream(fileInputStream);
bufferedInputStream.read(data,0,data.length);
//Now the bytes of the file are contain in the "byte[] data"
/*If you want to convert these bytes into a file, you have to write these bytes to a
certain location, then it will make a new file at that location if same named file is
not available at that location*/
FileOutputStream fileOutputStream =new FileOutputStream(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).toString()+"/Video.mp4");
fileOutputStream.write(data);
/* It will write or make a new file named Video.mp4 in the "Download" directory of
the External Storage */
I am experimenting with Java and created a small program that copies a file and generates a MD5 checksum. The program works and generates a checksum, but the resulting file that is copied does not match the original checksum.
I am new to Java and do not understand what the problem is here. Am I writing the wrong buffer to the output file?
package com.application;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
public class Main {
static int secure_copy(String src, String dest) throws Exception {
InputStream inFile = new FileInputStream(src);
OutputStream outFile = new FileOutputStream(dest);
MessageDigest md = MessageDigest.getInstance("MD5");
byte[] buf = new byte[1024];
int numRead;
do {
numRead = inFile.read(buf);
if (numRead > 0) {
md.update(buf, 0, numRead);
outFile.write(buf);
outFile.flush();
}
} while (numRead != -1);
inFile.close();
outFile.close();
BigInteger no = new BigInteger(1, md.digest());
String result = no.toString(16);
while(result.length() < 32) {
result = "0" + result;
}
System.out.println("MD5: " + result);
return 0;
}
public static void main(String[] args) {
try {
secure_copy(args[0], args[1]);
} catch (Exception e) {
System.out.println("Error: " + e.getMessage());
}
}
}
Output from source file: (Correct)
MD5: 503ea121d2bc6f1a2ede8eb47f0d13ef
The file from the copy function, checked via md5sum
md5sum file.mov
56883109c28590c33fb31cc862619977 file.mov
You are writing the entire buffer to the output file, not just the portion that has data from the latest read. The fix is simple:
if (numRead > 0) {
md.update(buf, 0, numRead);
outFile.write(buf, 0, numRead);
}
On every read from the InputStream, the code is continually changing the data to calculate the hash of. Instead of calling md.update(buf, 0, numRead); within the loop, it should read the entire file into a byte[] and then call md.update(entireFileByeArray) once. (See this answer for a way to find the appropriate array size ahead of opening the file.)
I'm new to java and need some understanding on below.
private static void decompressGzipFile(String gzipFile, String newFile) {
try {
FileInputStream fis = new FileInputStream(gzipFile);
GZIPInputStream gis = new GZIPInputStream(fis);
FileOutputStream fos = new FileOutputStream(newFile);
byte[] buffer = new byte[1024];
int len;
while((len = gis.read(buffer)) != -1){
fos.write(buffer, 0, len);
}
//close resources
System.out.println("Decompression is successful");
fos.close();
gis.close();
} catch (IOException e) {
e.printStackTrace();
}
I have some data in compressed GZIP file which is in
í?]o£F ?s?_1RoZ?Öó?¹Ã?d¬ÅÆ[1]?U.?¦Q?8²?Dù÷=?íÄÃÌ ?VUUÎM´d Î?÷|Ì?Í?7ÉöaõÇjûzö³
?9 ??Á¤?? ?? fs?c?;î&Äq?3?Ú?>ÙËv·Ü t¶Y¯w¦uM¿ÿ?Z²?Æò?
________________________________________
[hº~Biþ?F
________________________________________
ÎÁ?bâ??OÃÙ[1]Yã0ó'Q?¬?x?¡ ?â
This is byte data and how can I convert this to string format or readable format in java?
I tried using GZip Uncompressor to read this file but that give me the same file as output but I want the data to be in human readable format. I tried using GZIPInputStream and base64inputStream but that gives incorrect data type. I'm not sure if this is really byte data or how to read this data? any suggestions please help
FileOutputStream bydefault writes data into files using encoding.
If you want to skip encoding , use BufferedReader
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.zip.GZIPInputStream;
public class ZipFileReader{
public static void main(String[] args) throws IOException {
GZIPInputStream zipFile = new GZIPInputStream(new FileInputStream("C:/Users/HimanshuSharma2/Downloads/phayes-geoPHP-1.2-20-g6855624.tar.gz"));
BufferedReader br = new BufferedReader(new InputStreamReader(zipFile));
String content;
while ((content = br.readLine()) != null)
System.out.println(content);
}
}
checked on sample file from this link: https://github.com/phayes/geoPHP/tarball/master
and finally write this string into file.
I have to upload a zip file into BLOB using informatica, for this task, I am using java transformation. Using the following code, I was able to upload all the flat files and retrieve them from the database table in correct format.
This code is not working for zip files. Can you please suggest me on how to convert a zip file into a binary file so that it can be inserted into BLOB?
byte bytes[] = null;
File f1 = new File(TARGETFILE);
try (FileInputStream fis = new FileInputStream(f1)) {
try (ByteArrayOutputStream baos = new ByteArrayOutputStream()) {
byte[] buffer = new byte[1024];
int read = -1;
while ((read = fis.read(buffer)) != -1) {
baos.write(buffer, 0, read);
}
bytes = baos.toByteArray();
FILE_CONTENT=bytes;
FILE_SIZE=Double.toString(f1.length()/1024*1024);
}
catch(Exception e1) {
}
}
catch (IOException exp) {
exp.printStackTrace();
}
A very simple version, just converts the data to a hex print. Using these parts you should be able to get to binary no problem. Just save the conversion to memory rather then print the string.
package test;
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.util.Arrays;
/**
*
* #author User
*/
public class Test {
/**
* #param args the command line arguments
*/
public static void main(String[] args) {
File file = new File("C:\\Users\\User\\Downloads\\ltc1298-arduino-library-master.zip");
byte[] bytes = new byte[(int)file.length()];
try {
DataInputStream dataInputStream = new DataInputStream(new BufferedInputStream(new FileInputStream("C:\\Users\\User\\Downloads\\ltc1298-arduino-library-master.zip")));
dataInputStream.readFully(bytes);
System.out.println(String.format(Arrays.toString(bytes)));
for (byte b : bytes) {
System.out.format("0x%x ", b);
}
dataInputStream.close();
}
catch (Exception e) {
System.out.println("Error");
e.printStackTrace();
}
}
}
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.