Read file to byte array and save byte array to file
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
public class Util{
/**
* Read bytes from a File into a byte[].
*
* @param file The File to read.
* @return A byte[] containing the contents of the File.
* @throws IOException Thrown if the File is too long to read or couldn't be
* read fully.
*/
public static byte[] readBytesFromFile(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) {
throw new IOException("Could not completely read file " + file.getName() + " as it is too long (" + length + " bytes, max supported " + Integer.MAX_VALUE + ")");
}
// Create the byte array to hold the data
byte[] bytes = new byte[(int)length];
// 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;
}
/**
* Writes the specified byte[] to the specified File path.
*
* @param theFile File Object representing the path to write to.
* @param bytes The byte[] of data to write to the File.
* @throws IOException Thrown if there is problem creating or writing the
* File.
*/
public static void writeBytesToFile(File theFile, byte[] bytes) throws IOException {
BufferedOutputStream bos = null;
try {
FileOutputStream fos = new FileOutputStream(theFile);
bos = new BufferedOutputStream(fos);
bos.write(bytes);
}finally {
if(bos != null) {
try {
//flush and close the BufferedOutputStream
bos.flush();
bos.close();
} catch(Exception e){}
}
}
}
}
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