Overview | Package | Class | Use | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

## org.apache.poi.util
Class IOUtils

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

    public final class IOUtils

extends java.lang.Object

Method Summary
`static long` | `calculateChecksum(byte[] data)` Calculate checksum on input data
`static long` | `calculateChecksum(java.io.InputStream stream)` Calculate checksum on all the data read from input stream.
`static void` | `closeQuietly(java.io.Closeable closeable)` Quietly (no exceptions) close Closable resource.
`static void` | `copy(java.io.InputStream inp, java.io.OutputStream out)` Copies all the data from the given InputStream to the OutputStream.
`static byte[]` | `peekFirst8Bytes(java.io.InputStream stream)` Peeks at the first 8 bytes of the stream.
`static byte[]` | `peekFirstNBytes(java.io.InputStream stream, int limit)` Peeks at the first N bytes of the stream.
`static int` | `readFully(java.io.InputStream in, byte[] b)` Helper method, just calls `readFully(in, b, 0, b.length)`
`static int` | `readFully(java.io.InputStream in, byte[] b, int off, int len)` Same as the normal `InputStream.read(byte[], int, int)`, but tries to ensure that the entire len number of bytes is read.
`static int` | `readFully(java.nio.channels.ReadableByteChannel channel, java.nio.ByteBuffer b)` Same as the normal `channel.read(b)`, but tries to ensure that the buffer is filled completely if possible, i.e.
`static byte[]` | `safelyAllocate(long length, int maxLength)`
`static long` | `skipFully(java.io.InputStream input, long toSkip)` Skips bytes from an input byte stream.
`static byte[]` | `toByteArray(java.nio.ByteBuffer buffer, int length)` Returns an array (that shouldn't be written to!) of the ByteBuffer.
`static byte[]` | `toByteArray(java.io.InputStream stream)` Reads all the data from the input stream, and returns the bytes read.
`static byte[]` | `toByteArray(java.io.InputStream stream, int length)` Reads up to `length` bytes from the input stream, and returns the bytes read.
`static void` | `write(POIDocument doc, java.io.OutputStream out)` Write a POI Document (`Workbook`, `SlideShow`, etc) to an output stream and close the output stream.
`static void` | `write(Workbook doc, java.io.OutputStream out)` Write a (`Workbook`) to an output stream and close the output stream.
`static void` | `writeAndClose(POIDocument doc)` Like `writeAndClose(POIDocument, File)`, but for writing a POI Document in place (to the same file that it was opened from).
`static void` | `writeAndClose(POIDocument doc, java.io.File out)` Like `writeAndClose(POIDocument, OutputStream)`, but for writing to a File instead of an OutputStream.
`static void` | `writeAndClose(POIDocument doc, java.io.OutputStream out)` Write a POI Document (`Workbook`, `SlideShow`, etc) to an output stream and close the output stream.
`static void` | `writeAndClose(Workbook doc, java.io.OutputStream out)`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Method Detail

### peekFirst8Bytes

    public static byte[] peekFirst8Bytes(java.io.InputStream stream)
                                  throws java.io.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
    `java.io.IOException`

### peekFirstNBytes

    public static byte[] peekFirstNBytes(java.io.InputStream stream,
                                         int limit)
                                  throws java.io.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
    `java.io.IOException`

### toByteArray

    public static byte[] toByteArray(java.io.InputStream stream)
                              throws java.io.IOException

  Reads all the data from the input stream, and returns the bytes read.

  Throws:
    `java.io.IOException`

### toByteArray

    public static byte[] toByteArray(java.io.InputStream stream,
                                     int length)
                              throws java.io.IOException

  Reads up to `length` bytes from the input stream, and returns the bytes read.

  Throws:
    `java.io.IOException`

### toByteArray

    public static byte[] toByteArray(java.nio.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(java.io.InputStream in,
                                byte[] b)
                         throws java.io.IOException

  Helper method, just calls `readFully(in, b, 0, b.length)`

  Throws:
    `java.io.IOException`

### readFully

    public static int readFully(java.io.InputStream in,
                                byte[] b,
                                int off,
                                int len)
                         throws java.io.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:
    `java.io.IOException`

### readFully

    public static int readFully(java.nio.channels.ReadableByteChannel channel,
                                java.nio.ByteBuffer b)
                         throws java.io.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:
    `java.io.IOException`

### write

    public static void write(POIDocument doc,
                             java.io.OutputStream out)
                      throws java.io.IOException

  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:
    `java.io.IOException` - thrown on errors writing to the stream

### write

    public static void write(Workbook doc,
                             java.io.OutputStream out)
                      throws java.io.IOException

  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:
    `java.io.IOException` - thrown on errors writing to the stream

### writeAndClose

    public static void writeAndClose(POIDocument doc,
                                     java.io.OutputStream out)
                              throws java.io.IOException

  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:
    `java.io.IOException` - thrown on errors writing to the stream

### writeAndClose

    public static void writeAndClose(POIDocument doc,
                                     java.io.File out)
                              throws java.io.IOException

  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:
    `java.io.IOException` - thrown on errors writing to the stream

### writeAndClose

    public static void writeAndClose(POIDocument doc)
                              throws java.io.IOException

  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:
    `java.io.IOException` - thrown on errors writing to the file

### writeAndClose

    public static void writeAndClose(Workbook doc,
                                     java.io.OutputStream out)
                              throws java.io.IOException

  Throws:
    `java.io.IOException`

### copy

    public static void copy(java.io.InputStream inp,
                            java.io.OutputStream out)
                     throws java.io.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.

  Throws:
    `java.io.IOException`

### calculateChecksum

    public static long calculateChecksum(byte[] data)

  Calculate checksum on input data

### calculateChecksum

    public static long calculateChecksum(java.io.InputStream stream)
                                  throws java.io.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:
    `java.io.IOException`

### closeQuietly

    public static void closeQuietly(java.io.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(java.io.InputStream input,
                                 long toSkip)
                          throws java.io.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:
    `java.io.IOException` - if there is a problem reading the file
    `java.lang.IllegalArgumentException` - if toSkip is negative
  See Also:
    `InputStream.skip(long)`

### safelyAllocate

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

Overview | Package | Class | Use | Tree | Deprecated | Index | Help
PREV CLASS NEXT CLASS | FRAMES NO FRAMES
SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD

Copyright 2017 The Apache Software Foundation or its licensors, as applicable.