java.util.zip

Class ZipInputStream

java.lang.Object

java.io.InputStream

java.io.FilterInputStream

java.util.zip.InflaterInputStream

java.util.zip.ZipInputStream

All Implemented Interfaces:

Closeable, AutoCloseable

public class ZipInputStream
extends InflaterInputStream

This class implements an input stream filter for reading files in the ZIP file format. Includes support for both compressed and uncompressed entries.

Author:

David Connelly

Field Summary

Fields

Modifier and Type	Field and Description
static int	CENATT
static int	CENATX
static int	CENCOM
static int	CENCRC
static int	CENDSK
static int	CENEXT
static int	CENFLG
static int	CENHDR
static int	CENHOW
static int	CENLEN
static int	CENNAM
static int	CENOFF
static long	CENSIG
static int	CENSIZ
static int	CENTIM
static int	CENVEM
static int	CENVER
static int	ENDCOM
static int	ENDHDR
static int	ENDOFF
static long	ENDSIG
static int	ENDSIZ
static int	ENDSUB
static int	ENDTOT
static int	EXTCRC
static int	EXTHDR
static int	EXTLEN
static long	EXTSIG
static int	EXTSIZ
static int	LOCCRC
static int	LOCEXT
static int	LOCFLG
static int	LOCLEN
static int	LOCNAM
static long	LOCSIG
static int	LOCSIZ
static int	LOCTIM
static int	LOCVER
static int	LOCHDR
static int	LOCHOW

Fields inherited from class java.util.zip.InflaterInputStream

buf, inf, len

Fields inherited from class java.io.FilterInputStream

in

Constructor Summary

Constructors

Constructor and Description
ZipInputStream(InputStream in) Creates a new ZIP input stream.

Method Summary

Methods

Modifier and Type	Method and Description
int	available() Returns 0 after EOF has reached for the current entry data, otherwise always return 1.
void	close() Closes this input stream and releases any system resources associated with the stream.
void	closeEntry() Closes the current ZIP entry and positions the stream for reading the next entry.
protected ZipEntry	createZipEntry(String name) Creates a new ZipEntry object for the specified entry name.
ZipEntry	getNextEntry() Reads the next ZIP file entry and positions the stream at the beginning of the entry data.
void	mark(int readlimit) Marks the current position in this input stream.
boolean	markSupported() Tests if this input stream supports the mark and reset methods.
int	read() Reads a byte of uncompressed data.
int	read(byte[] b) Reads up to byte.length bytes of data from this input stream into an array of bytes.
int	read(byte[] b, int off, int len) Reads from the current ZIP entry into an array of bytes.
void	reset() Repositions this stream to the position at the time the mark method was last called on this input stream.
long	skip(long n) Skips specified number of bytes in the current ZIP entry.

Methods inherited from class java.util.zip.InflaterInputStream

fill

Methods inherited from class java.lang.Object

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

Field Detail

LOCSIG

public static final long LOCSIG

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Constant Field Values

EXTSIG

public static final long EXTSIG

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Constant Field Values

CENSIG

public static final long CENSIG

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ENDSIG

public static final long ENDSIG

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Constant Field Values

LOCHDR

public static final int LOCHDR

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EXTHDR

public static final int EXTHDR

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CENHDR

public static final int CENHDR

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ENDHDR

public static final int ENDHDR

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LOCVER

public static final int LOCVER

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LOCFLG

public static final int LOCFLG

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LOCHOW

public static final int LOCHOW

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LOCTIM

public static final int LOCTIM

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LOCCRC

public static final int LOCCRC

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LOCSIZ

public static final int LOCSIZ

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LOCLEN

public static final int LOCLEN

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LOCNAM

public static final int LOCNAM

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LOCEXT

public static final int LOCEXT

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EXTCRC

public static final int EXTCRC

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EXTSIZ

public static final int EXTSIZ

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EXTLEN

public static final int EXTLEN

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CENVEM

public static final int CENVEM

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CENVER

public static final int CENVER

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CENFLG

public static final int CENFLG

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CENHOW

public static final int CENHOW

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CENTIM

public static final int CENTIM

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CENCRC

public static final int CENCRC

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CENSIZ

public static final int CENSIZ

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CENLEN

public static final int CENLEN

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CENNAM

public static final int CENNAM

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CENEXT

public static final int CENEXT

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CENCOM

public static final int CENCOM

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CENDSK

public static final int CENDSK

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CENATT

public static final int CENATT

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CENATX

public static final int CENATX

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CENOFF

public static final int CENOFF

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ENDSUB

public static final int ENDSUB

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ENDTOT

public static final int ENDTOT

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ENDSIZ

public static final int ENDSIZ

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ENDOFF

public static final int ENDOFF

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ENDCOM

public static final int ENDCOM

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Constant Field Values

Constructor Detail

ZipInputStream

public ZipInputStream(InputStream in)

Creates a new ZIP input stream.

The UTF-8 charset is used to decode the entry names.

Parameters:

in - the actual input stream

Method Detail

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 after EOF has reached for the current entry data, otherwise always return 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:

1 before EOF and 0 after EOF has reached for current entry.

Throws:

IOException - if an I/O error occurs.

read

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

Reads from the current ZIP entry into an array of bytes. If len is not zero, the method blocks until some input is available; otherwise, no bytes are read and 0 is returned.

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 specified number of bytes in 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

close

public void close()
           throws IOException

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

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

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

read

public int read()
         throws IOException

Description copied from class: InflaterInputStream

Reads a byte of uncompressed data. This method will block until enough input is available for decompression.

Overrides:

read in class InflaterInputStream

Returns:

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

Throws:

IOException - if an I/O error has occurred

See Also:

FilterInputStream.in

markSupported

public boolean markSupported()

Description copied from class: InflaterInputStream

Tests if this input stream supports the mark and reset methods. The markSupported method of InflaterInputStream returns false.

Overrides:

markSupported in class InflaterInputStream

Returns:

a boolean indicating if this stream type supports the mark and reset methods.

See Also:

InputStream.mark(int), InputStream.reset()

mark

public void mark(int readlimit)

Description copied from class: InflaterInputStream

Marks the current position in this input stream.

The mark method of InflaterInputStream does nothing.

Overrides:

mark in class InflaterInputStream

Parameters:

readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.

See Also:

InputStream.reset()

reset

public void reset()
           throws IOException

Description copied from class: InflaterInputStream

Repositions this stream to the position at the time the mark method was last called on this input stream.

The method reset for class InflaterInputStream does nothing except throw an IOException.

Overrides:

reset in class InflaterInputStream

Throws:

IOException - if this method is invoked.

See Also:

InputStream.mark(int), IOException

read

public int read(byte[] b)
         throws IOException

Description copied from class: FilterInputStream

Reads up to byte.length bytes of data from this input stream into an array of bytes. This method blocks until some input is available.

This method simply performs the call read(b, 0, b.length) and returns the result. It is important that it does not do in.read(b) instead; certain subclasses of FilterInputStream depend on the implementation strategy actually used.

Overrides:

read in class FilterInputStream

Parameters:

b - the buffer into which the data is read.

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.

Throws:

IOException - if an I/O error occurs.

See Also:

FilterInputStream.read(byte[], int, int)