Class ByteStreams



  • @Beta
    public final class ByteStreams
    extends Object
    Provides utility methods for working with byte arrays and I/O streams.
    Since:
    1.0
    • Method Detail

      • copy

        public static long copy(InputStream from,
                                OutputStream to)
                         throws IOException
        Copies all bytes from the input stream to the output stream. Does not close or flush either stream.
        Parameters:
        from - the input stream to read from
        to - the output stream to write to
        Returns:
        the number of bytes copied
        Throws:
        IOException - if an I/O error occurs
      • copy

        public static long copy(ReadableByteChannel from,
                                WritableByteChannel to)
                         throws IOException
        Copies all bytes from the readable channel to the writable channel. Does not close or flush either channel.
        Parameters:
        from - the readable channel to read from
        to - the writable channel to write to
        Returns:
        the number of bytes copied
        Throws:
        IOException - if an I/O error occurs
      • toByteArray

        public static byte[] toByteArray(InputStream in)
                                  throws IOException
        Reads all bytes from an input stream into a byte array. Does not close the stream.
        Parameters:
        in - the input stream to read from
        Returns:
        a byte array containing all the bytes from the stream
        Throws:
        IOException - if an I/O error occurs
      • newDataInput

        public static ByteArrayDataInput newDataInput(ByteArrayInputStream byteArrayInputStream)
        Returns a new ByteArrayDataInput instance to read from the given ByteArrayInputStream. The given input stream is not reset before being read from by the returned ByteArrayDataInput.
        Since:
        17.0
      • newDataOutput

        public static ByteArrayDataOutput newDataOutput(ByteArrayOutputStream byteArrayOutputSteam)
        Returns a new ByteArrayDataOutput instance which writes to the given ByteArrayOutputStream. The given output stream is not reset before being written to by the returned ByteArrayDataOutput and new data will be appended to any existing content.

        Note that if the given output stream was not empty or is modified after the ByteArrayDataOutput is created, the contract for ByteArrayDataOutput.toByteArray() will not be honored (the bytes returned in the byte array may not be exactly what was written via calls to ByteArrayDataOutput).

        Since:
        17.0
      • nullOutputStream

        public static OutputStream nullOutputStream()
        Returns an OutputStream that simply discards written bytes.
        Since:
        14.0 (since 1.0 as com.google.common.io.NullOutputStream)
      • limit

        public static InputStream limit(InputStream in,
                                        long limit)
        Wraps a InputStream, limiting the number of bytes which can be read.
        Parameters:
        in - the input stream to be wrapped
        limit - the maximum number of bytes to be read
        Returns:
        a length-limited InputStream
        Since:
        14.0 (since 1.0 as com.google.common.io.LimitInputStream)
      • readFully

        public static void readFully(InputStream in,
                                     byte[] b)
                              throws IOException
        Attempts to read enough bytes from the stream to fill the given byte array, with the same behavior as DataInput.readFully(byte[]). Does not close the stream.
        Parameters:
        in - the input stream to read from.
        b - the buffer into which the data is read.
        Throws:
        EOFException - if this stream reaches the end before reading all the bytes.
        IOException - if an I/O error occurs.
      • readFully

        public static void readFully(InputStream in,
                                     byte[] b,
                                     int off,
                                     int len)
                              throws IOException
        Attempts to read len bytes from the stream into the given array starting at off, with the same behavior as DataInput.readFully(byte[], int, int). Does not close the stream.
        Parameters:
        in - the input stream to read from.
        b - the buffer into which the data is read.
        off - an int specifying the offset into the data.
        len - an int specifying the number of bytes to read.
        Throws:
        EOFException - if this stream reaches the end before reading all the bytes.
        IOException - if an I/O error occurs.
      • skipFully

        public static void skipFully(InputStream in,
                                     long n)
                              throws IOException
        Discards n bytes of data from the input stream. This method will block until the full amount has been skipped. Does not close the stream.
        Parameters:
        in - the input stream to read from
        n - the number of bytes to skip
        Throws:
        EOFException - if this stream reaches the end before skipping all the bytes
        IOException - if an I/O error occurs, or the stream does not support skipping
      • readBytes

        public static <T> T readBytes(InputStream input,
                                      ByteProcessor<T> processor)
                               throws IOException
        Process the bytes of the given input stream using the given processor.
        Parameters:
        input - the input stream to process
        processor - the object to which to pass the bytes of the stream
        Returns:
        the result of the byte processor
        Throws:
        IOException - if an I/O error occurs
        Since:
        14.0
      • read

        public static int read(InputStream in,
                               byte[] b,
                               int off,
                               int len)
                        throws IOException
        Reads some bytes from an input stream and stores them into the buffer array b. This method blocks until len bytes of input data have been read into the array, or end of file is detected. The number of bytes read is returned, possibly zero. Does not close the stream.

        A caller can detect EOF if the number of bytes read is less than len. All subsequent calls on the same stream will return zero.

        If b is null, a NullPointerException is thrown. If off is negative, or len is negative, or off+len is greater than the length of the array b, then an IndexOutOfBoundsException is thrown. If len is zero, then no bytes are read. Otherwise, the first byte read is stored into element b[off], the next one into b[off+1], and so on. The number of bytes read is, at most, equal to len.

        Parameters:
        in - the input stream to read from
        b - the buffer into which the data is read
        off - an int specifying the offset into the data
        len - an int specifying the number of bytes to read
        Returns:
        the number of bytes read
        Throws:
        IOException - if an I/O error occurs