org.apache.commons.compress.archivers.zip

Class ZipArchiveInputStream

java.lang.Object

java.io.InputStream

org.apache.commons.compress.archivers.ArchiveInputStream

org.apache.commons.compress.archivers.zip.ZipArchiveInputStream

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, InputStreamStatistics

Direct Known Subclasses:

JarArchiveInputStream

public class ZipArchiveInputStream
extends ArchiveInputStream
implements InputStreamStatistics

Implements an input stream that can read Zip archives.

As of Apache Commons Compress it transparently supports Zip64 extensions and thus individual entries and archives larger than 4 GB or with more than 65536 entries.

The ZipFile class is preferred when reading from files as ZipArchiveInputStream is limited by not being able to read the central directory header before returning entries. In particular ZipArchiveInputStream

• may return entries that are not part of the central directory at all and shouldn't be considered part of the archive.
• may return several entries with the same name.
• will not return internal or external attributes.
• may return incomplete extra field data.
• may return unknown sizes and CRC values for entries until the next entry has been reached if the archive uses the data descriptor feature.

See Also:

ZipFile

Constructor Summary

Constructors

Constructor and Description
ZipArchiveInputStream(java.io.InputStream inputStream) Create an instance using UTF-8 encoding
ZipArchiveInputStream(java.io.InputStream inputStream, java.lang.String encoding) Create an instance using the specified encoding
ZipArchiveInputStream(java.io.InputStream inputStream, java.lang.String encoding, boolean useUnicodeExtraFields) Create an instance using the specified encoding
ZipArchiveInputStream(java.io.InputStream inputStream, java.lang.String encoding, boolean useUnicodeExtraFields, boolean allowStoredEntriesWithDataDescriptor) Create an instance using the specified encoding

Method Summary

Modifier and Type	Method and Description
boolean	canReadEntryData(ArchiveEntry ae) Whether this class is able to read the given entry.
void	close()
long	getCompressedCount()
ArchiveEntry	getNextEntry() Returns the next Archive Entry in this Stream.
ZipArchiveEntry	getNextZipEntry()
long	getUncompressedCount()
static boolean	matches(byte[] signature, int length) Checks if the signature matches what is expected for a zip file.
int	read(byte[] buffer, int offset, int length)
long	skip(long value) Skips over and discards value bytes of data from this input stream.

Methods inherited from class org.apache.commons.compress.archivers.ArchiveInputStream

getBytesRead, getCount, read

Methods inherited from class java.io.InputStream

available, mark, markSupported, read, reset

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ZipArchiveInputStream

public ZipArchiveInputStream(java.io.InputStream inputStream)

Create an instance using UTF-8 encoding

Parameters:

inputStream - the stream to wrap

ZipArchiveInputStream

public ZipArchiveInputStream(java.io.InputStream inputStream,
                             java.lang.String encoding)

Create an instance using the specified encoding

Parameters:

inputStream - the stream to wrap

encoding - the encoding to use for file names, use null for the platform's default encoding

Since:

1.5

ZipArchiveInputStream

public ZipArchiveInputStream(java.io.InputStream inputStream,
                             java.lang.String encoding,
                             boolean useUnicodeExtraFields)

Create an instance using the specified encoding

Parameters:

inputStream - the stream to wrap

encoding - the encoding to use for file names, use null for the platform's default encoding

useUnicodeExtraFields - whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.

ZipArchiveInputStream

public ZipArchiveInputStream(java.io.InputStream inputStream,
                             java.lang.String encoding,
                             boolean useUnicodeExtraFields,
                             boolean allowStoredEntriesWithDataDescriptor)

Create an instance using the specified encoding

Parameters:

inputStream - the stream to wrap

encoding - the encoding to use for file names, use null for the platform's default encoding

useUnicodeExtraFields - whether to use InfoZIP Unicode Extra Fields (if present) to set the file names.

allowStoredEntriesWithDataDescriptor - whether the stream will try to read STORED entries that use a data descriptor

Since:

1.1

Method Detail

getNextZipEntry

public ZipArchiveEntry getNextZipEntry()
                                throws java.io.IOException

Throws:

java.io.IOException

getNextEntry

public ArchiveEntry getNextEntry()
                          throws java.io.IOException

Description copied from class: ArchiveInputStream

Returns the next Archive Entry in this Stream.

Specified by:

getNextEntry in class ArchiveInputStream

Returns:

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

Throws:

java.io.IOException - if the next entry could not be read

canReadEntryData

public boolean canReadEntryData(ArchiveEntry ae)

Whether this class is able to read the given entry.

May return false if it is set up to use encryption or a compression method that hasn't been implemented yet.

Overrides:

canReadEntryData in class ArchiveInputStream

Parameters:

ae - the entry to test

Returns:

This implementation always returns true.

Since:

1.1

read

public int read(byte[] buffer,
                int offset,
                int length)
         throws java.io.IOException

Overrides:

read in class java.io.InputStream

Throws:

java.io.IOException

getCompressedCount

public long getCompressedCount()

Specified by:

getCompressedCount in interface InputStreamStatistics

Returns:

the amount of raw or compressed bytes read by the stream

Since:

1.17

getUncompressedCount

public long getUncompressedCount()

Specified by:

getUncompressedCount in interface InputStreamStatistics

Returns:

the amount of decompressed bytes returned by the stream

Since:

1.17

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Overrides:

close in class java.io.InputStream

Throws:

java.io.IOException

skip

public long skip(long value)
          throws java.io.IOException

Skips over and discards value bytes of data from this input stream.

This implementation may end up skipping over some smaller number of bytes, possibly 0, if and only if it reaches the end of the underlying stream.

The actual number of bytes skipped is returned.

Overrides:

skip in class java.io.InputStream

Parameters:

value - the number of bytes to be skipped.

Returns:

the actual number of bytes skipped.

Throws:

java.io.IOException - - if an I/O error occurs.

java.lang.IllegalArgumentException - - if value is negative.

matches

public static boolean matches(byte[] signature,
                              int length)

Checks if the signature matches what is expected for a zip file. Does not currently handle self-extracting zips which may have arbitrary leading content.

Parameters:

signature - the bytes to check

length - the number of bytes to check

Returns:

true, if this stream is a zip archive stream, false otherwise