Example usage for java.io RandomAccessFile read

Introduction

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

Prototype

public int read(byte b[]) throws IOException

Source Link

Document

Reads up to b.length bytes of data from this file into an array of bytes.

Usage

From source file:org.mhisoft.common.util.FileUtils.java

public static String readString(RandomAccessFile raFile) throws IOException {
    int numBytes = FileUtils.readInt(raFile);
    byte[] _byte = new byte[numBytes];
    int readBytes = raFile.read(_byte);
    if (readBytes != numBytes)
        throw new RuntimeException(
                "readString() failed, " + "read " + readBytes + " bytes only, expected to read:" + numBytes);

    return StringUtils.bytesToString(_byte);

}

From source file:jsave.Utils.java

/**
 * Reads a Byte (-128 to 127).// w  w  w .ja  va2  s  . co  m
 *
 * @param raf the file where the 4 Bytes are read
 * @return a Byte
 */
private static short read_UnsignedByte(RandomAccessFile raf) {
    byte[] data = new byte[1];
    byte byteData = -1;
    try {
        raf.read(data);
        ByteBuffer bb = ByteBuffer.allocate(data.length);
        bb.put(data);
        return getUnsignedByte(bb);
    } catch (IOException e) {
    }

    return byteData;
}

From source file:jsave.Utils.java

/**
 * Reads an Integer (-32768 to 32767)/*from  www  . j ava2  s . co m*/
 *
 * @param raf the 4 Bytes where the file is read
 * @return a short Integer
 */
private static short read_int16(RandomAccessFile raf) {
    byte[] data = new byte[2];
    short shortData = -1;
    try {
        raf.read(data);
        shortData = ByteBuffer.wrap(data).getShort();
    } catch (IOException e) {
    }

    return shortData;
}

From source file:jsave.Utils.java

/**
 * Reads a Single precision float (sign bit, 8 bits exponent, 23 bits
 * mantissa)./*from   w w  w .  j  a  va2  s  .c o  m*/
 *
 * @param raf the 4 Bytes where the file is read
 * @return a Single precision float (sign bit, 8 bits exponent, 23 bits
 * mantissa)
 */
private static float read_float32(RandomAccessFile raf) {
    byte[] data = new byte[4];
    float floatData = -1;
    try {
        raf.read(data);
        floatData = ByteBuffer.wrap(data).getFloat();

    } catch (IOException e) {
    }

    return floatData;
}

From source file:jsave.Utils.java

/**
 * Reads a Double precision float: sign bit, 11 bits exponent, 52 bits
 * mantissa// w w  w  . j av a 2  s  .com
 *
 * @param raf the file where the bytes are read
 * @return a Double precision float
 */
private static double read_float64(RandomAccessFile raf) {
    byte[] data = new byte[8];
    double floatData = -1;
    try {
        raf.read(data);
        floatData = ByteBuffer.wrap(data).getDouble();
    } catch (IOException e) {
    }

    return floatData;
}

From source file:eionet.eunis.servlets.DownloadServlet.java

/**
 * Copy the given byte range of the given input to the given output.
 *
 * @param input The input to copy the given range to the given output for.
 * @param output The output to copy the given range from the given input for.
 * @param start Start of the byte range.
 * @param length Length of the byte range.
 * @throws IOException If something fails at I/O level.
 *//*from   ww  w .j a v a2 s  . co m*/
private static void copy(RandomAccessFile input, OutputStream output, long start, long length)
        throws IOException {
    byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
    int read;

    if (input.length() == length) {
        // Write full range.
        while ((read = input.read(buffer)) > 0) {
            output.write(buffer, 0, read);
        }
    } else {
        // Write partial range.
        input.seek(start);
        long toRead = length;

        while ((read = input.read(buffer)) > 0) {
            toRead = toRead - read;
            if (toRead > 0) {
                output.write(buffer, 0, read);
            } else {
                output.write(buffer, 0, (int) toRead + read);
                break;
            }
        }
    }
}

From source file:jsave.Utils.java

public static String read_string(final RandomAccessFile raf) throws IOException {
    int length = read_long(raf);
    String result;//w w  w. j a v  a 2s . c  om
    if (length > 0) {
        byte[] data = new byte[length];
        raf.read(data);
        align_32(raf);
        result = new String(data, StandardCharsets.UTF_8);
    } else {
        result = "";
    }
    return result;
}

From source file:jsave.Utils.java

public static String read_string_data(final RandomAccessFile raf) throws IOException {
    int length = read_long(raf);
    String result;/*  w  w w . ja  v a2 s . c  om*/
    if (length > 0) {
        length = read_long(raf);
        byte[] data = new byte[length];
        raf.read(data);
        align_32(raf);
        result = new String(data, StandardCharsets.UTF_8);
    } else {
        result = "";
    }
    return result;
}

From source file:com.hdsfed.cometapi.HCPClient.java

/**
 * Copy the given byte range of the given input to the given output.
 * @param input The input to copy the given range to the given output for.
 * @param output The output to copy the given range from the given input for.
 * @param start Start of the byte range.
 * @param length Length of the byte range.
 * @throws IOException If something fails at I/O level.
 *//*from  www . j  a va 2  s .  c om*/
public static void FileToOutputStream(RandomAccessFile input, OutputStream output, long start, long length)
        throws IOException {
    byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
    int read;

    if (input.length() == length) {
        // Write full range.
        while ((read = input.read(buffer)) > 0) {
            output.write(buffer, 0, read);
        }
    } else {
        // Write partial range.
        input.seek(start);
        long toRead = length;

        while ((read = input.read(buffer)) > 0) {
            if ((toRead -= read) > 0) {
                output.write(buffer, 0, read);
            } else {
                output.write(buffer, 0, (int) toRead + read);
                break;
            }
        }
    }
}

From source file:net.yacy.document.importer.MediawikiImporter.java

public static byte[] read(final File f, final long start, final int len) {
    final byte[] b = new byte[len];
    RandomAccessFile raf = null;
    try {//w  w  w . j  av a2 s  .  c o  m
        raf = new RandomAccessFile(f, "r");
        raf.seek(start);
        raf.read(b);
    } catch (final IOException e) {
        ConcurrentLog.logException(e);
        return null;
    } finally {
        if (raf != null)
            try {
                raf.close();
                try {
                    raf.getChannel().close();
                } catch (final IOException e) {
                }
            } catch (final IOException e) {
            }
    }
    return b;
}