把一个文件转化成byte[] 数组

啥都不说了，给一个文件，返回给byte数组

// read the photo file into a byte array...public static byte[] getBytesFromFile(File file) throws IOException {InputStream is = new FileInputStream(file);// Get the size of the filelong 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 databyte[] bytes = new byte[(int) length];// Read in the bytesint 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 inif (offset < bytes.length) {throw new IOException("Could not completely read file "+ file.getName());}// Close the input stream and return bytesis.close();return bytes;}