Class ZipInputStream

Method Details

• getNextEntry

  public ZipEntry getNextEntry() throws IOException

  Reads the next ZIP file entry and positions the stream at the beginning of the entry data.

  Returns:

  the next ZIP file entry, or null if there are no more entries

  Throws:

  ZipException - if a ZIP file error has occurred

  IOException - if an I/O error has occurred

• closeEntry

  public void closeEntry() throws IOException

  Closes the current ZIP entry and positions the stream for reading the next entry.

  Throws:

  ZipException - if a ZIP file error has occurred

  IOException - if an I/O error has occurred

• available

  public int available() throws IOException

  Returns 0 when end of stream is detected for the current ZIP entry or closeEntry() has been called on the current ZIP entry, otherwise returns 1.

  Programs should not count on this method to return the actual number of bytes that could be read without blocking.

  Overrides:

  available in class InflaterInputStream

  Returns:

  0 when end of stream is detected for the current ZIP entry or closeEntry() has been called on the current ZIP entry, otherwise 1.

  Throws:

  IOException - if an I/O error occurs.

• read

  public int read() throws IOException

  Reads the next byte of data from the input stream for the current ZIP entry. This method will block until enough input is available for decompression.

  Overrides:

  read in class InflaterInputStream

  Returns:

  the byte read, or -1 if the end of the stream is reached

  Throws:

  IOException - if an I/O error has occurred

  See Also:

  • FilterInputStream.in

• readAllBytes

  public byte[] readAllBytes() throws IOException

  Reads all remaining bytes from the input stream for the current ZIP entry. This method blocks until all remaining bytes have been read and end of stream is detected, or an exception is thrown. This method does not close the input stream.

  When this stream reaches end of stream, further invocations of this method will return an empty byte array.

  Note that this method is intended for simple cases where it is convenient to read all bytes into a byte array. It is not intended for reading input streams with large amounts of data.

  If an I/O error occurs reading from the input stream, then it may do so after some, but not all, bytes have been read. Consequently, the input stream may not be at end of stream and may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.

  Overrides:

  readAllBytes in class InputStream

  Returns:

  a byte array containing the bytes read from this input stream

  Throws:

  OutOfMemoryError - if an array of the required size cannot be allocated.

  IOException - if an I/O error occurs

  Since:

  9

• readNBytes

  public byte[] readNBytes(int len) throws IOException

  Reads up to a specified number of bytes from the input stream for the current ZIP entry. This method blocks until the requested number of bytes has been read, end of stream is detected, or an exception is thrown. This method does not close the input stream.

  The length of the returned array equals the number of bytes read from the stream. If len is zero, then no bytes are read and an empty byte array is returned. Otherwise, up to len bytes are read from the stream. Fewer than len bytes may be read if end of stream is encountered.

  When this stream reaches end of stream, further invocations of this method will return an empty byte array.

  Note that this method is intended for simple cases where it is convenient to read the specified number of bytes into a byte array. The total amount of memory allocated by this method is proportional to the number of bytes read from the stream which is bounded by len. Therefore, the method may be safely called with very large values of len provided sufficient memory is available.

  If an I/O error occurs reading from the input stream, then it may do so after some, but not all, bytes have been read. Consequently, the input stream may not be at end of stream and may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.

  Overrides:

  readNBytes in class InputStream

  Implementation Note:

  This method calls super.readNBytes(int len).

  Parameters:

  len - the maximum number of bytes to read

  Returns:

  a byte array containing the bytes read from this input stream

  Throws:

  OutOfMemoryError - if an array of the required size cannot be allocated.

  IOException - if an I/O error occurs

  Since:

  11

• readNBytes

  public int readNBytes(byte[] b, int off, int len) throws IOException

  Reads the requested number of bytes from the input stream into the given byte array for the current ZIP entry returning the number of inflated bytes. This method blocks until len bytes of input data have been read, end of stream is detected, or an exception is thrown. The number of bytes actually read, possibly zero, is returned. This method does not close the input stream.

  In the case where end of stream is reached before len bytes have been read, then the actual number of bytes read will be returned. When this stream reaches end of stream, further invocations of this method will return zero.

  If len is zero, then no bytes are read and 0 is returned; otherwise, there is an attempt to read up to len bytes.

  The first byte read is stored into element b[off], the next one in to b[off+1], and so on. The number of bytes read is, at most, equal to len. Let k be the number of bytes actually read; these bytes will be stored in elements b[off] through b[off+k-1], leaving elements b[off+k ] through b[off+len-1] unaffected.

  If an I/O error occurs reading from the input stream, then it may do so after some, but not all, bytes of b have been updated with data from the input stream. Consequently, the input stream and b may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.

  Overrides:

  readNBytes in class InputStream

  Parameters:

  b - the byte array into which the data is read

  off - the start offset in b at which the data is written

  len - the maximum number of bytes to read

  Returns:

  the actual number of bytes read into the buffer

  Throws:

  NullPointerException - if b is null

  IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off

  IOException - if an I/O error occurs

  Since:

  9

• skipNBytes

  public void skipNBytes(long n) throws IOException

  Skips over and discards exactly n bytes of data from this input stream for the current ZIP entry. If n is zero, then no bytes are skipped. If n is negative, then no bytes are skipped. Subclasses may handle the negative value differently.

  This method blocks until the requested number of bytes has been skipped, end of file is reached, or an exception is thrown.

  If end of stream is reached before the stream is at the desired position, then an EOFException is thrown.

  If an I/O error occurs, then the input stream may be in an inconsistent state. It is strongly recommended that the stream be promptly closed if an I/O error occurs.

  Overrides:

  skipNBytes in class InputStream

  Parameters:

  n - the number of bytes to be skipped.

  Throws:

  IOException - if the stream cannot be positioned properly or if an I/O error occurs.

  Since:

  12

  See Also:

  • InputStream.skip(long)

• transferTo

  public long transferTo(OutputStream out) throws IOException

  Reads all bytes from this input stream for the current ZIP entry and writes the bytes to the given output stream in the order that they are read. On return, this input stream will be at end of stream. This method does not close either stream.

  This method may block indefinitely reading from the input stream, or writing to the output stream. The behavior for the case where the input and/or output stream is asynchronously closed, or the thread interrupted during the transfer, is highly input and output stream specific, and therefore not specified.

  If the total number of bytes transferred is greater than Long.MAX_VALUE, then Long.MAX_VALUE will be returned.

  If an I/O error occurs reading from the input stream or writing to the output stream, then it may do so after some bytes have been read or written. Consequently, the input stream may not be at end of stream and one, or both, streams may be in an inconsistent state. It is strongly recommended that both streams be promptly closed if an I/O error occurs.

  Overrides:

  transferTo in class InputStream

  Parameters:

  out - the output stream, non-null

  Returns:

  the number of bytes transferred

  Throws:

  NullPointerException - if out is null

  IOException - if an I/O error occurs when reading or writing

  Since:

  9

• read

  public int read(byte[] b, int off, int len) throws IOException

  Reads the requested number of bytes from the input stream into the given byte array for the current ZIP entry returning the number of inflated bytes. If len is not zero, the method blocks until some input is available; otherwise, no bytes are read and 0 is returned.

  If the current entry is compressed and this method returns a nonzero integer n then buf[off] through buf[off+n-1] contain the uncompressed data. The content of elements buf[off+n] through buf[off+len-1] is undefined, contrary to the specification of the InputStream superclass, so an implementation is free to modify these elements during the inflate operation. If this method returns -1 or throws an exception then the content of buf[off] through buf[off+len -1] is undefined.

  Overrides:

  read in class InflaterInputStream

  Parameters:

  b - the buffer into which the data is read

  off - the start offset in the destination array b

  len - the maximum number of bytes read

  Returns:

  the actual number of bytes read, or -1 if the end of the entry is reached

  Throws:

  NullPointerException - if b is null.

  IndexOutOfBoundsException - if off is negative, len is negative, or len is greater than b.length - off

  ZipException - if a ZIP file error has occurred

  IOException - if an I/O error has occurred

  See Also:

  • FilterInputStream.in

• skip

  public long skip(long n) throws IOException

  Skips over and discards n bytes of data from this input stream for the current ZIP entry.

  Overrides:

  skip in class InflaterInputStream

  Parameters:

  n - the number of bytes to skip

  Returns:

  the actual number of bytes skipped

  Throws:

  ZipException - if a ZIP file error has occurred

  IOException - if an I/O error has occurred

  IllegalArgumentException - if n < 0

  See Also:

  • InputStream.skipNBytes(long)

• close

  public void close() throws IOException

  Closes this input stream and releases any system resources associated with the stream.

  Specified by:

  close in interface AutoCloseable

  Specified by:

  close in interface Closeable

  Overrides:

  close in class InflaterInputStream

  Throws:

  IOException - if an I/O error has occurred

  See Also:

  • FilterInputStream.in

• createZipEntry

  protected ZipEntry createZipEntry(String name)

  Creates a new ZipEntry object for the specified entry name.

  Parameters:

  name - the ZIP file entry name

  Returns:

  the ZipEntry just created