Example usage for java.io RandomAccessFile RandomAccessFile

Introduction

In this page you can find the example usage for java.io RandomAccessFile RandomAccessFile.

Prototype

public RandomAccessFile(File file, String mode) throws FileNotFoundException

Source Link

Document

Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument.

Usage

From source file:com.filelocker.encryption.AES_Encryption.java

/**
 * If a file is being decrypted, we need to know the pasword, the salt and the initialization vector (iv).
 * We have the password from initializing the class. pass the iv and salt here which is
 * obtained when encrypting the file initially.
 *
 * @param inFile - The Encrypted File containing encrypted data , salt and InitVec
 * @throws NoSuchAlgorithmException//  w  w  w  .  j a va  2  s .c om
 * @throws InvalidKeySpecException
 * @throws NoSuchPaddingException
 * @throws InvalidKeyException
 * @throws InvalidAlgorithmParameterException
 * @throws DecoderException
 * @throws IOException
 */
public void setupDecrypt(File inFile)
        throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, InvalidKeyException,
        InvalidAlgorithmParameterException, DecoderException, IOException {
    SecretKeyFactory factory = null;
    SecretKey tmp = null;
    SecretKey secret = null;

    byte[] vSalt = new byte[8];
    byte[] vInitVec = new byte[16];

    RandomAccessFile vFile = new RandomAccessFile(inFile, "rw");

    //The last 8 bits are salt so seek to length of file minus 9 bits
    vFile.seek(vFile.length() - 8);
    vFile.readFully(vSalt);

    //The last 8 bits are salt and 16 bits before last 8 are Initialization Vectory so 8+16=24
    //Thus to seek to length of file minus 24 bits
    vFile.seek(vFile.length() - 24);
    vFile.readFully(vInitVec);
    vFile.seek(0);

    File tmpFile = new File(inFile.getAbsolutePath() + ".tmpEncryption.file");

    RandomAccessFile vTmpFile = new RandomAccessFile(tmpFile, "rw");

    for (int i = 0; i < (vFile.length() - 24); ++i) {
        vTmpFile.write(vFile.readByte());
    }
    vFile.close();
    vTmpFile.close();

    inFile.delete();
    tmpFile.renameTo(inFile);

    Db("got salt " + Hex.encodeHexString(vSalt));

    Db("got initvector :" + Hex.encodeHexString(vInitVec));

    /* Derive the key, given password and salt. */
    // in order to do 256 bit crypto, you have to muck with the files for Java's "unlimted security"
    // The end user must also install them (not compiled in) so beware.
    // see here:
    // http://www.javamex.com/tutorials/cryptography/unrestricted_policy_files.shtml
    // PBKDF2WithHmacSHA1,Constructs secret keys using the Password-Based Key Derivation Function function
    //found in PKCS #5 v2.0. (PKCS #5: Password-Based Cryptography Standard)

    factory = SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
    KeySpec spec = new PBEKeySpec(vPassword.toCharArray(), vSalt, ITERATIONS, KEYLEN_BITS);

    tmp = factory.generateSecret(spec);
    secret = new SecretKeySpec(tmp.getEncoded(), "AES");

    // Decrypt the message, given derived key and initialization vector.
    vDecipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
    vDecipher.init(Cipher.DECRYPT_MODE, secret, new IvParameterSpec(vInitVec));
}

From source file:com.aliyun.odps.volume.VolumeFSInputStream.java

private synchronized InputStream getLocalInputStream(long index) throws FileNotFoundException, IOException {
    if (!seekOptimization) {
        return null;
    }//from ww  w.  j ava  2 s . c  o  m
    isCache = true;
    File blockFile = new File(buffer_block_dir, getBlockFileName(index));
    raf = new RandomAccessFile(blockFile, "r");
    return Channels.newInputStream(raf.getChannel().position(pos - curIndex * blockSize));
}

From source file:de.cosmocode.palava.store.FileSystemStore.java

@Override
public ByteBuffer view(String identifier) throws IOException {
    Preconditions.checkNotNull(identifier, "Identifier");
    final File file = getFile(identifier);
    Preconditions.checkState(file.exists(), "%s does not exist", file);
    LOG.trace("Reading file from {}", file);
    final FileChannel channel = new RandomAccessFile(file, "r").getChannel();
    return channel.map(MapMode.READ_ONLY, 0, channel.size());
}

From source file:com.geekandroid.sdk.pay.utils.Util.java

public static byte[] readFromFile(String fileName, int offset, int len) {
    if (fileName == null) {
        return null;
    }/*  www .j av a2s  .  c  o m*/

    File file = new File(fileName);
    if (!file.exists()) {
        Log.i(TAG, "readFromFile: file not found");
        return null;
    }

    if (len == -1) {
        len = (int) file.length();
    }

    Log.d(TAG, "readFromFile : offset = " + offset + " len = " + len + " offset + len = " + (offset + len));

    if (offset < 0) {
        Log.e(TAG, "readFromFile invalid offset:" + offset);
        return null;
    }
    if (len <= 0) {
        Log.e(TAG, "readFromFile invalid len:" + len);
        return null;
    }
    if (offset + len > (int) file.length()) {
        Log.e(TAG, "readFromFile invalid file len:" + file.length());
        return null;
    }

    byte[] b = null;
    try {
        RandomAccessFile in = new RandomAccessFile(fileName, "r");
        b = new byte[len]; // ??
        in.seek(offset);
        in.readFully(b);
        in.close();

    } catch (Exception e) {
        Log.e(TAG, "readFromFile : errMsg = " + e.getMessage());
        e.printStackTrace();
    }
    return b;
}

From source file:com.sun.faban.harness.webclient.ResultAction.java

private String editResultInfo(String runID) throws FileNotFoundException, IOException {
    RunId runId = new RunId(runID);
    String ts = null;//  ww w . j  a va2  s  .  c om
    String[] status = new String[2];
    File file = new File(Config.OUT_DIR + runID + '/' + Config.RESULT_INFO);
    RandomAccessFile rf = new RandomAccessFile(file, "rwd");
    long size = rf.length();
    byte[] buffer = new byte[(int) size];
    rf.readFully(buffer);
    String content = new String(buffer, 0, (int) size);
    int idx = content.indexOf('\t');
    if (idx != -1) {
        status[0] = content.substring(0, idx).trim();
        status[1] = content.substring(++idx).trim();
    } else {
        status[0] = content.trim();
        int lastIdxln = status[0].lastIndexOf("\n");
        if (lastIdxln != -1)
            status[0] = status[0].substring(0, lastIdxln - 1);
    }
    if (status[1] != null) {
        ts = status[1];
    } else {
        String paramFileName = runId.getResultDir().getAbsolutePath() + File.separator + "run.xml";
        File paramFile = new File(paramFileName);
        long dt = paramFile.lastModified();
        ts = dateFormat.format(new Date(dt));
        rf.seek(rf.length());
        rf.writeBytes('\t' + ts.trim());
    }
    rf.close();
    return ts;
}

From source file:dk.statsbiblioteket.util.LineReaderTest.java

public void testVsRandomAccess() throws Exception {
    RandomAccessFile ra = new RandomAccessFile(logfile, "r");
    LineReader lr = new LineReader(logfile, "r");
    int count = 0;
    while (count++ < LINES) {
        assertEquals("The lr line should match ra line", ++count + "'" + fixISO(ra.readLine()) + "'",
                count + "'" + lr.readLine() + "'");
    }//w  ww .  ja v a  2s . c o m
}

From source file:com.sangupta.snowpack.SnowpackRecover.java

/**
 * Try and recover from a chunk./*from  w  w w . j  a  va  2 s .co m*/
 * 
 * @param chunkID
 * @param chunkFile
 * @param metadataDB 
 * @return
 * @throws IOException 
 */
private static ChunkInfo recoverChunkInfo(final int chunkID, final File chunkFile,
        SnowpackMetadataDB metadataDB) throws IOException {
    // open the file for reading
    RandomAccessFile raf = new RandomAccessFile(chunkFile, "r");

    // read the length first
    int nameLength, length, terminator, headerLength, numFiles = 0;
    long offset;

    List<FlakeMetadata> metas = new ArrayList<FlakeMetadata>();

    try {
        while (raf.getFilePointer() < raf.length()) {
            offset = raf.getFilePointer();

            nameLength = raf.readInt();
            byte[] name = new byte[nameLength];
            raf.readFully(name);

            length = raf.readInt();
            raf.readLong();
            raf.skipBytes((int) length);

            terminator = raf.readByte();
            if (terminator != 0) {
                System.out.print(" invalid descriptor found...");
                return null;
            }

            headerLength = 4 + name.length + 4 + 8;

            numFiles++;

            metas.add(new FlakeMetadata(new String(name), nameLength, chunkID, offset, headerLength));
        }
    } finally {
        raf.close();
    }

    // all clear for recovery

    // save all metadata in new DB
    for (FlakeMetadata meta : metas) {
        metadataDB.save(meta);
    }

    // return chunk info
    ChunkInfo info = new ChunkInfo();
    info.chunkID = chunkID;
    info.numFiles = numFiles;
    info.writePointer = -1;

    return info;
}

From source file:com.slytechs.capture.StreamFactory.java

public InputCapture<? extends CapturePacket> newInput(final File file,
        final Filter<ProtocolFilterTarget> filter) throws IOException {

    final BufferedInputStream b = new BufferedInputStream(new FileInputStream(file));
    b.mark(1024); // Buffer first 1K of stream so we can rewind

    /*/*ww w. j av a2s.  c o m*/
     * Check the stream, without decompression first
     */
    if (formatType(Channels.newChannel(b)) != null) {
        b.close();

        /*
         * This is a plain uncompressed file, open up a FileChannel. It will be
         * much faster
         */
        return newInput(new RandomAccessFile(file, "rw").getChannel(), filter);
    }

    /*
     * Try with gunziped stream, second
     */
    b.reset(); // Rewind
    if (formatType(Channels.newChannel(new GZIPInputStream(b))) != null) {
        b.close();

        /*
         * Now reopen the same file, but this time without the buffered
         * inputstream in the middle. Try to make things as efficient as possible.
         * TODO: implement much faster channel based GZIP decompression algorithm
         */
        return newInput(Channels.newChannel(new GZIPInputStream(new FileInputStream(file))), filter);
    }

    b.close();
    return factoryForOther.getFactory().newInput(new RandomAccessFile(file, "r").getChannel(), filter);

}

From source file:io.ecarf.core.utils.Utils.java

/**
 * Get the likely uncompressed size of a Gziped file
 * @param filename// w  w  w  .j a v  a 2 s  .com
 * @return
 * @throws IOException 
 * @see http://stackoverflow.com/questions/27825927/get-gzipped-file-attributes-like-gzip-l-basically-compression-ratio
 * @throws FileNotFoundException 
 */
public static long getUncompressedFileSize(String filename) throws FileNotFoundException, IOException {

    File f = new File(filename);
    try (RandomAccessFile ra = new RandomAccessFile(f, "r"); FileChannel channel = ra.getChannel()) {

        MappedByteBuffer fileBuffer = channel.map(MapMode.READ_ONLY, f.length() - 4, 4);
        fileBuffer.load();

        ByteBuffer buf = ByteBuffer.allocate(4);
        buf.order(ByteOrder.LITTLE_ENDIAN);

        buf.put(fileBuffer);
        buf.flip();
        //will print the uncompressed size
        //getInt() reads the 4 bytes as a int
        // if the file is between 2GB and 4GB
        // then this will return a negative value
        //and you'll have to do your own converting to an unsigned int
        int size = buf.getInt();

        if (size < 0) {
            return FileUtils.ONE_GB + size;
        } else {
            return size;
        }
    }
}

From source file:com.bigdata.dastor.io.SSTableReader.java

private static MappedByteBuffer mmap(String filename, long start, int size) throws IOException {
    RandomAccessFile raf;//from www.  j av a2s .  co  m
    try {
        raf = new RandomAccessFile(filename, "r");
    } catch (FileNotFoundException e) {
        throw new IOError(e);
    }

    try {
        return raf.getChannel().map(FileChannel.MapMode.READ_ONLY, start, size);
    } finally {
        raf.close();
    }
}