Class IOUtils

java.lang.Object
org.apache.poi.util.IOUtils

public final class IOUtils extends Object
  • Method Details

    • setByteArrayMaxOverride

      public static void setByteArrayMaxOverride(int maxOverride)
      If this value is set to > 0, safelyAllocate(long, int) will ignore the maximum record length parameter. This is designed to allow users to bypass the hard-coded maximum record lengths if they are willing to accept the risk of an OutOfMemoryException.
      Parameters:
      maxOverride - The number of bytes that should be possible to be allocated in one step.
      Since:
      4.0.0
    • peekFirst8Bytes

      public static byte[] peekFirst8Bytes(InputStream stream) throws IOException, EmptyFileException
      Peeks at the first 8 bytes of the stream. Returns those bytes, but with the stream unaffected. Requires a stream that supports mark/reset, or a PushbackInputStream. If the stream has >0 but <8 bytes, remaining bytes will be zero.
      Throws:
      EmptyFileException - if the stream is empty
      IOException
    • peekFirstNBytes

      public static byte[] peekFirstNBytes(InputStream stream, int limit) throws IOException, EmptyFileException
      Peeks at the first N bytes of the stream. Returns those bytes, but with the stream unaffected. Requires a stream that supports mark/reset, or a PushbackInputStream. If the stream has >0 but <N bytes, remaining bytes will be zero.
      Throws:
      EmptyFileException - if the stream is empty
      IOException
    • toByteArray

      public static byte[] toByteArray(InputStream stream) throws IOException
      Reads all the data from the input stream, and returns the bytes read.
      Parameters:
      stream - The byte stream of data to read.
      Returns:
      A byte array with the read bytes.
      Throws:
      IOException - If reading data fails or EOF is encountered too early for the given length.
    • toByteArray

      public static byte[] toByteArray(InputStream stream, int length) throws IOException
      Reads up to length bytes from the input stream, and returns the bytes read.
      Parameters:
      stream - The byte stream of data to read.
      length - The maximum length to read, use Integer.MAX_VALUE to read the stream until EOF.
      Returns:
      A byte array with the read bytes.
      Throws:
      IOException - If reading data fails or EOF is encountered too early for the given length.
    • toByteArray

      public static byte[] toByteArray(InputStream stream, long length, int maxLength) throws IOException
      Reads up to length bytes from the input stream, and returns the bytes read.
      Parameters:
      stream - The byte stream of data to read.
      length - The maximum length to read, use Integer.MAX_VALUE to read the stream until EOF
      maxLength - if the input is equal to/longer than maxLength bytes, then throw an IOException complaining about the length. use Integer.MAX_VALUE to disable the check
      Returns:
      A byte array with the read bytes.
      Throws:
      IOException - If reading data fails or EOF is encountered too early for the given length.
    • toByteArray

      public static byte[] toByteArray(ByteBuffer buffer, int length)
      Returns an array (that shouldn't be written to!) of the ByteBuffer. Will be of the requested length, or possibly longer if that's easier.
    • readFully

      public static int readFully(InputStream in, byte[] b) throws IOException
      Helper method, just calls readFully(in, b, 0, b.length)
      Throws:
      IOException
    • readFully

      public static int readFully(InputStream in, byte[] b, int off, int len) throws IOException

      Same as the normal InputStream.read(byte[], int, int), but tries to ensure that the entire len number of bytes is read.

      If the end of file is reached before any bytes are read, returns -1. If the end of the file is reached after some bytes are read, returns the number of bytes read. If the end of the file isn't reached before len bytes have been read, will return len bytes.

      Parameters:
      in - the stream from which the data is read.
      b - the buffer into which the data is read.
      off - the start offset in array b at which the data is written.
      len - the maximum number of bytes to read.
      Throws:
      IOException
    • readFully

      public static int readFully(ReadableByteChannel channel, ByteBuffer b) throws IOException
      Same as the normal channel.read(b), but tries to ensure that the buffer is filled completely if possible, i.e. b.remaining() returns 0.

      If the end of file is reached before any bytes are read, returns -1. If the end of the file is reached after some bytes are read, returns the number of bytes read. If the end of the file isn't reached before the buffer has no more remaining capacity, will return the number of bytes that were read.

      Throws:
      IOException
    • write

      @Deprecated @Removal(version="4.2") public static void write(POIDocument doc, OutputStream out) throws IOException
      Deprecated.
      since 4.0, use try-with-resources, will be removed in 4.2
      Write a POI Document (Workbook, SlideShow, etc) to an output stream and close the output stream. This will attempt to close the output stream at the end even if there was a problem writing the document to the stream. If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead. This function exists for Java 6 code.
      Parameters:
      doc - a writeable document to write to the output stream
      out - the output stream that the document is written to
      Throws:
      IOException - thrown on errors writing to the stream
    • write

      @Deprecated @Removal(version="4.2") public static void write(Workbook doc, OutputStream out) throws IOException
      Deprecated.
      since 4.0, use try-with-resources, will be removed in 4.2
      Write a (Workbook) to an output stream and close the output stream. This will attempt to close the output stream at the end even if there was a problem writing the document to the stream. If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead. This function exists for Java 6 code.
      Parameters:
      doc - a writeable document to write to the output stream
      out - the output stream that the document is written to
      Throws:
      IOException - thrown on errors writing to the stream
    • writeAndClose

      @Deprecated @Removal(version="4.2") public static void writeAndClose(POIDocument doc, OutputStream out) throws IOException
      Deprecated.
      since 4.0, use try-with-resources, will be removed in 4.2
      Write a POI Document (Workbook, SlideShow, etc) to an output stream and close the output stream. This will attempt to close the output stream at the end even if there was a problem writing the document to the stream. This will also attempt to close the document, even if an error occurred while writing the document or closing the output stream. If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead. This function exists for Java 6 code.
      Parameters:
      doc - a writeable and closeable document to write to the output stream, then close
      out - the output stream that the document is written to
      Throws:
      IOException - thrown on errors writing to the stream
    • writeAndClose

      @Deprecated @Removal(version="4.2") public static void writeAndClose(POIDocument doc, File out) throws IOException
      Deprecated.
      since 4.0, use try-with-resources, will be removed in 4.2
      Like writeAndClose(POIDocument, OutputStream), but for writing to a File instead of an OutputStream. This will attempt to close the document, even if an error occurred while writing the document. If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead. This function exists for Java 6 code.
      Parameters:
      doc - a writeable and closeable document to write to the output file, then close
      out - the output file that the document is written to
      Throws:
      IOException - thrown on errors writing to the stream
    • writeAndClose

      @Deprecated @Removal(version="4.2") public static void writeAndClose(POIDocument doc) throws IOException
      Deprecated.
      since 4.0, use try-with-resources, will be removed in 4.2
      Like writeAndClose(POIDocument, File), but for writing a POI Document in place (to the same file that it was opened from). This will attempt to close the document, even if an error occurred while writing the document. If you are using Java 7 or higher, you may prefer to use a try-with-resources statement instead. This function exists for Java 6 code.
      Parameters:
      doc - a writeable document to write in-place
      Throws:
      IOException - thrown on errors writing to the file
    • writeAndClose

      @Deprecated @Removal(version="4.2") public static void writeAndClose(Workbook doc, OutputStream out) throws IOException
      Deprecated.
      since 4.0, use try-with-resources, will be removed in 4.2
      Throws:
      IOException
    • copy

      public static long copy(InputStream inp, OutputStream out) throws IOException
      Copies all the data from the given InputStream to the OutputStream. It leaves both streams open, so you will still need to close them once done.
      Parameters:
      inp - The InputStream which provides the data
      out - The OutputStream to write the data to
      Returns:
      the amount of bytes copied
      Throws:
      IOException - If copying the data fails.
    • copy

      public static long copy(InputStream srcStream, File destFile) throws IOException
      Copy the contents of the stream to a new file.
      Parameters:
      srcStream - The InputStream which provides the data
      destFile - The file where the data should be stored
      Returns:
      the amount of bytes copied
      Throws:
      IOException - If the target directory does not exist and cannot be created or if copying the data fails.
    • calculateChecksum

      public static long calculateChecksum(byte[] data)
      Calculate checksum on input data
    • calculateChecksum

      public static long calculateChecksum(InputStream stream) throws IOException
      Calculate checksum on all the data read from input stream. This should be more efficient than the equivalent code IOUtils.calculateChecksum(IOUtils.toByteArray(stream))
      Throws:
      IOException
    • closeQuietly

      public static void closeQuietly(Closeable closeable)
      Quietly (no exceptions) close Closable resource. In case of error it will be printed to IOUtils class logger.
      Parameters:
      closeable - resource to close
    • skipFully

      public static long skipFully(InputStream input, long toSkip) throws IOException
      Skips bytes from an input byte stream. This implementation guarantees that it will read as many bytes as possible before giving up; this may not always be the case for skip() implementations in subclasses of InputStream.

      Note that the implementation uses InputStream.read(byte[], int, int) rather than delegating to InputStream.skip(long). This means that the method may be considerably less efficient than using the actual skip implementation, this is done to guarantee that the correct number of bytes are skipped.

      This mimics POI's readFully(InputStream, byte[]). If the end of file is reached before any bytes are read, returns -1. If the end of the file is reached after some bytes are read, returns the number of bytes read. If the end of the file isn't reached before len bytes have been read, will return len bytes.

      Copied nearly verbatim from commons-io 41a3e9c

      Parameters:
      input - byte stream to skip
      toSkip - number of bytes to skip.
      Returns:
      number of bytes actually skipped.
      Throws:
      IOException - if there is a problem reading the file
      IllegalArgumentException - if toSkip is negative
      See Also:
    • safelyAllocate

      public static byte[] safelyAllocate(long length, int maxLength)
    • readByte

      public static int readByte(InputStream is) throws IOException
      Simple utility function to check that you haven't hit EOF when reading a byte.
      Parameters:
      is - inputstream to read
      Returns:
      byte read, unless
      Throws:
      IOException - on IOException or EOF if -1 is read