Hi guys i trying to convert a pdf file to byte array but it dosn't work for me when i trying to get the file from the classPath resource using the classLoader and after that transform it to byte array it doesn't work i don't have a null array but the getting array length it's not ok and when i write this byte array as a file i have an damaged file and i can't opend it.
A last thing when i trying to get the file using the path like (c://java//files//test.pdf) it's working and byte array length it's ok and when i write the array as a file i have exactly the some file in input. another thing the getting file length using classLoader and using path is exactly the some
My code is :
public static void main(String[] args) {
try {
// convert file to byte[]
byte[] bFile = readBytesFromFile("C:\\TEMP\\test.pdf");
byte[] bytes = readBytesFromFileResources();
System.out.println(bFile.length);//60255
System.out.println(bytes.length);//14463
}
private static byte[] readBytesFromFile(String filePath) {
FileInputStream fileInputStream = null;
byte[] bytesArray = null;
try {
File file = new File(filePath);
bytesArray = new byte[(int) file.length()];
//read file into bytes[]
fileInputStream = new FileInputStream(file);
fileInputStream.read(bytesArray);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (fileInputStream != null) {
try {
fileInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return bytesArray;
}
private static byte[] readBytesFromFileResources() {
ClassLoader classLoader = ReadFile.class.getClassLoader();
File file = new File(classLoader.getResource("test.pdf").getFile());
FileInputStream fileInputStream = null;
byte[] bytesArray = null;
try {
bytesArray = new byte[(int) file.length()];
//read file into bytes[]
fileInputStream = new FileInputStream(file);
fileInputStream.read(bytesArray);
} catch (IOException e) {
e.printStackTrace();
} finally {
if (fileInputStream != null) {
try {
fileInputStream.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return bytesArray;
}
A last thing when i trying to get the file using the path like
(c://java//files//test.pdf) it's working and byte array length it's ok
and when i write the array as a file i have exactly the some file in
input.
c://java//files//test.pdf is probably not in the classpath.
So, you cannot use the classloader to load the file as the classloader will not be able to find it.
Either you move the file in the classpath (if it makes sense), either you load the file with the filesystem dependent way as you write in your question :
File file = new file("c://java//files//test.pdf)";
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 have a requirement to create a zip file from input stream data, and before writing to zip I need to find the checksum for the input stream.
To do that I am using below codes:
private String writeZipFileToFS(List<ResponsePacks> attachmentList) throws IOException
{
File fileToWrite = new File(getZipPath() + "fileName.zip");
try
{
FileUtils.copyInputStreamToFile(compress(attachmentList), fileToWrite);
}
catch (IOException e)
{
throw e;
}
return fileName;
}
private InputStream compress(List<ResponsePacks> attachmentList)
{
byte buffer[] = new byte[2048];
ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
ZipOutputStream zipFileToSend = new ZipOutputStream(byteStream);
try
{
for (ResponsePacks info : attachmentList)
{
// only for successful requests files would need to be added
zipFileToSend.putNextEntry(new ZipEntry(info.getFileName()));
InputStream in = info.getFileContentStream();
getCheckSum(in, info.getFileName());
int length;
while ((length = in.read(buffer)) >= 0)
{
zipFileToSend.write(buffer, 0, length);
}
zipFileToSend.closeEntry();
}
zipFileToSend.close();
}
catch (IOException e)
{
throw e;
}
return new ByteArrayInputStream(byteStream.toByteArray());
}
private static void getCheckSum(InputStream is, String fileName)
{
byte[] dataCopy = null;
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
try
{
IOUtils.copy(is, outputStream);
dataCopy = outputStream.toByteArray();
printLog("Byte Array Size {}", dataCopy.length);
String checkSum = calculateChecksum(dataCopy);
printLog("Checksum for file {} {}", fileName, checkSum);
outputStream.flush();
outputStream.close();
}
catch (Exception e)
{
printLog("Error on calculationg checksum {}", e.getMessage());
}
}
private static String calculateChecksum(byte[] dataCopy)
{
try (ZipInputStream zipInputStream = new ZipInputStream(new ByteArrayInputStream(dataCopy)))
{
ZipEntry zipEntry;
MessageDigest digest = DigestUtils.getSha256Digest();
DWriter writer = new DWriter(digest);
while ((zipEntry = zipInputStream.getNextEntry()) != null)
{
byte[] entityData = IOUtils.toByteArray(zipInputStream);
if (!zipEntry.isDirectory())
{
writer.write(entityData);
}
}
if (writer.getChecksum() != null)
{
return writer.getChecksum();
}
}
catch (Exception e)
{
throw e;
}
return "";
}
static class DWriter
{
private final MessageDigest myDigest;
DWriter(MessageDigest digest)
{
myDigest = digest;
}
public void write(byte[] data)
{
myDigest.update(data);
}
public String getChecksum()
{
return new String(Hex.encodeHex(myDigest.digest()));
}
}
But problem is if I am adding code to calculate the checksum then zip file creating with empty content and if I am removing the checksum calculation code then zip file creating with proper contents.
And also when I check the log I found InputStream contents different contents but still I am getting the same checkSum (empty string) always as below:
Byte Array Size 20854
Checksum for file 20200910173919142.json e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
Byte Array Size 14383
Checksum for file 1599752440405.zip e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855
I am unable to find where I am doing wrong, due to which zip file is creating with empty content, and checkSum also creating same always.
Requesting to help me to find where I am doing wrong.
You consume twice the same inputstream: first you read it to get the checksum and the you read it again to write the zip entry.
getCheckSum(in, info.getFileName());
int length;
while ((length = in.read(buffer)) >= 0)
{
zipFileToSend.write(buffer, 0, length);
}
The second time you're trying to read, there's nothing to read anymore, so nothing gets written into the zip entry.
Some input streams can be reset and read multiple times, if that's not the case here you would need to save the data into a ByteArrayOutputStream (as you're already doing inside the getCheckSum() method), and then you could read that data multiple times.
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
String base64Code = dataInputStream.readUTF();
byte[] decodedString = null;
decodedString = Base64.decodeBase64(base64Code);
FileOutputStream imageOutFile = new FileOutputStream(
"E:/water-drop-after-convert.jpg");
imageOutFile.write(decodedString);
imageOutFile.close();
The problem is the data is transferred completely and if the data is in text format it is displayed correctly however when i am trying to decode image and write it on output file,it doesnt simply show up in photo viewer.
Any help would be highly appreciated
DataInputStream.readUTF may be the issue. This method assumes that the text was written to the file by DataOutputStream.writeUTF. If it is not so, and you are going to read a regular text, choose a different class, like BufferedReader or Scanner. Or Java 1.7's Files.readAllBytes.
Once I had to convert the Image into base 64 and sent that image as stream (encoding and decoding stuff here is the code)
To Convert a file into base64 :
String filePath = "E:\\water-drop-after-convert.jpg";
File bMap = new File(filePath);
byte[] bFile = new byte[(int) bMap.length()];
FileInputStream fileInputStream = null;
String imageFileBase64 = null;
try {
fileInputStream = new FileInputStream(bMap);
fileInputStream.read(bFile);
fileInputStream.close();
imageFileBase64 = Base64.encode(bFile);
}catch(Exception e){
e.printStackTrace();
}
then on service side I did thing like that to convert image in base 64 String back into file, so that i can display.
I had used this library on server side import sun.misc.BASE64Decoder;
//filePath is where you wana save image
String filePath = "E:\\water-drop-after-convert.jpg";
File imageFile = new File(filePath);
FileOutputStream fos = null;
try {
fos = new FileOutputStream(imageFile);
} catch (FileNotFoundException e1) {
e1.printStackTrace();
}
BASE64Decoder decoder = new BASE64Decoder();
byte[] decodedBytes = null;
try {
decodedBytes = decoder.decodeBuffer(imageFileBase64);//taking input string i.e the image contents in base 64
} catch (IOException e1) {
e1.printStackTrace();
}
try {
fos.write(decodedBytes);
} catch (IOException e) {
e.printStackTrace();
}
try {
fos.flush();
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
I have an application where Service A will provide a zipped data to Service B. And service B needs to unzip it.
Service A has an exposes method getStream and it gives ByteArrayInputStream as output and the data init is zipped data.
However passing that to GzipInputStream gives Not in Gzip format exception.
InputStream ins = method.getInputStream();
GZIPInputStream gis = new GZIPInputStream(ins);
This gives an exception. When the file is dumped in Service A the data is zipped. So getInputStream gives the zipped data.
How to process it ans pass it to the GzipInputStream?
Regards
Dheeraj Joshi
If it zipped, then you must use ZipInputstream.
It does depend on the "zip" format. There are multiple formats that have the zip name (zip, gzip, bzip2, lzip) and different formats call for different parsers.
http://en.wikipedia.org/wiki/List_of_archive_formats
http://www.codeguru.com/java/tij/tij0115.shtml
http://docstore.mik.ua/orelly/java-ent/jnut/ch25_01.htm
If you are using zip then try this code:
public void doUnzip(InputStream is, String destinationDirectory) throws IOException {
int BUFFER = 2048;
// make destination folder
File unzipDestinationDirectory = new File(destinationDirectory);
unzipDestinationDirectory.mkdir();
ZipInputStream zis = new ZipInputStream(is);
// Process each entry
for (ZipEntry entry = zis.getNextEntry(); entry != null; entry = zis
.getNextEntry()) {
File destFile = new File(unzipDestinationDirectory, entry.getName());
// create the parent directory structure if needed
destFile.getParentFile().mkdirs();
try {
// extract file if not a directory
if (!entry.isDirectory()) {
// establish buffer for writing file
byte data[] = new byte[BUFFER];
// write the current file to disk
FileOutputStream fos = new FileOutputStream(destFile);
BufferedOutputStream dest = new BufferedOutputStream(fos,
BUFFER);
// read and write until last byte is encountered
for (int bytesRead; (bytesRead = zis.read(data, 0, BUFFER)) != -1;) {
dest.write(data, 0, bytesRead);
}
dest.flush();
dest.close();
}
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
is.close();
}
public static void main(String[] args) {
UnzipInputStream unzip = new UnzipInputStream();
try {
InputStream fis = new FileInputStream(new File("test.zip"));
unzip.doUnzip(fis, "output");
} catch (IOException e) {
e.printStackTrace();
}
}