Package Summary  Overview Summary

class:ZipInputStream [CHANGED]

All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
JarInputStream

public class ZipInputStreamextends InflaterInputStream
This class implements anAn input stream filterfor reading filescompressed and uncompressed ZIP file entries from a stream of bytes in the ZIP file format.

Includes supportReading Zip File Entries

The getNextEntry() method is used to read the next ZIP file entry (Local file (LOC) header record in the ZIP format) and position the stream at the entry's file data. The file data may read using one of the ZipInputStream read methods such as read or readAllBytes(). For example:
  Path jar = Path.of("foo.jar");
  try (InputStream is = Files.newInputStream(jar);
       ZipInputStream zis = new ZipInputStream(is)) {
      ZipEntry ze;
      while((ze= zis.getNextEntry()) != null) {
         var bytes = zis.readAllBytes();
         System.out.printf("Entry: %s, bytes read: %s%n", ze.getName(),
                 bytes.length);
      }
  }

API Note:
The LOC header contains metadata about the Zip file entry. ZipInputStream does not read the Central directory (CEN) header for both compressedthe entry and uncompressed entriestherefore will not have access to its metadata such as the external file attributes. ZipFile may be used when the information stored within the CEN header is required.
Since:
1.1
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
JarInputStream

public class ZipInputStreamextends InflaterInputStream
This class implements an input stream filter for reading files in the ZIP file format. Includes support for both compressed and uncompressed entries.
Since:
1.1
All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
JarInputStream

public class ZipInputStreamextends InflaterInputStream
An input stream for reading compressed and uncompressed ZIP file entries from a stream of bytes in the ZIP file format.

Reading Zip File Entries

The getNextEntry() method is used to read the next ZIP file entry (Local file (LOC) header record in the ZIP format) and position the stream at the entry's file data. The file data may read using one of the ZipInputStream read methods such as read or readAllBytes(). For example:
  Path jar = Path.of("foo.jar");
  try (InputStream is = Files.newInputStream(jar);
       ZipInputStream zis = new ZipInputStream(is)) {
      ZipEntry ze;
      while((ze= zis.getNextEntry()) != null) {
         var bytes = zis.readAllBytes();
         System.out.printf("Entry: %s, bytes read: %s%n", ze.getName(),
                 bytes.length);
      }
  }

API Note:
The LOC header contains metadata about the Zip file entry. ZipInputStream does not read the Central directory (CEN) header for the entry and therefore will not have access to its metadata such as the external file attributes. ZipFile may be used when the information stored within the CEN header is required.
Since:
1.1

field:LOCSIG [NONE]

  • LOCSIG

    static final  long LOCSIG
    Local file (LOC) header signature.
    See Also:
  • field:EXTSIG [NONE]

    EXTSIG

    static final  long EXTSIG
    Extra local (EXT) header signature.
    See Also:

    field:CENSIG [NONE]

    CENSIG

    static final  long CENSIG
    Central directory (CEN) header signature.
    See Also:

    field:ENDSIG [NONE]

    ENDSIG

    static final  long ENDSIG
    End of central directory (END) header signature.
    See Also:

    field:LOCHDR [NONE]

    LOCHDR

    static final  int LOCHDR
    Local file (LOC) header size in bytes (including signature).
    See Also:

    field:EXTHDR [NONE]

    EXTHDR

    static final  int EXTHDR
    Extra local (EXT) header size in bytes (including signature).
    See Also:

    field:CENHDR [NONE]

    CENHDR

    static final  int CENHDR
    Central directory (CEN) header size in bytes (including signature).
    See Also:

    field:ENDHDR [NONE]

    ENDHDR

    static final  int ENDHDR
    End of central directory (END) header size in bytes (including signature).
    See Also:

    field:LOCVER [NONE]

    LOCVER

    static final  int LOCVER
    Local file (LOC) header version needed to extract field offset.
    See Also:

    field:LOCFLG [NONE]

    LOCFLG

    static final  int LOCFLG
    Local file (LOC) header general purpose bit flag field offset.
    See Also:

    field:LOCHOW [NONE]

    LOCHOW

    static final  int LOCHOW
    Local file (LOC) header compression method field offset.
    See Also:

    field:LOCTIM [NONE]

    LOCTIM

    static final  int LOCTIM
    Local file (LOC) header modification time field offset.
    See Also:

    field:LOCCRC [NONE]

    LOCCRC

    static final  int LOCCRC
    Local file (LOC) header uncompressed file crc-32 value field offset.
    See Also:

    field:LOCSIZ [NONE]

    LOCSIZ

    static final  int LOCSIZ
    Local file (LOC) header compressed size field offset.
    See Also:

    field:LOCLEN [NONE]

    LOCLEN

    static final  int LOCLEN
    Local file (LOC) header uncompressed size field offset.
    See Also:

    field:LOCNAM [NONE]

    LOCNAM

    static final  int LOCNAM
    Local file (LOC) header filename length field offset.
    See Also:

    field:LOCEXT [NONE]

    LOCEXT

    static final  int LOCEXT
    Local file (LOC) header extra field length field offset.
    See Also:

    field:EXTCRC [NONE]

    EXTCRC

    static final  int EXTCRC
    Extra local (EXT) header uncompressed file crc-32 value field offset.
    See Also:

    field:EXTSIZ [NONE]

    EXTSIZ

    static final  int EXTSIZ
    Extra local (EXT) header compressed size field offset.
    See Also:

    field:EXTLEN [NONE]

    EXTLEN

    static final  int EXTLEN
    Extra local (EXT) header uncompressed size field offset.
    See Also:

    field:CENVEM [NONE]

    CENVEM

    static final  int CENVEM
    Central directory (CEN) header version made by field offset.
    See Also:

    field:CENVER [NONE]

    CENVER

    static final  int CENVER
    Central directory (CEN) header version needed to extract field offset.
    See Also:

    field:CENFLG [NONE]

    CENFLG

    static final  int CENFLG
    Central directory (CEN) header encrypt, decrypt flags field offset.
    See Also:

    field:CENHOW [NONE]

    CENHOW

    static final  int CENHOW
    Central directory (CEN) header compression method field offset.
    See Also:

    field:CENTIM [NONE]

    CENTIM

    static final  int CENTIM
    Central directory (CEN) header modification time field offset.
    See Also:

    field:CENCRC [NONE]

    CENCRC

    static final  int CENCRC
    Central directory (CEN) header uncompressed file crc-32 value field offset.
    See Also:

    field:CENSIZ [NONE]

    CENSIZ

    static final  int CENSIZ
    Central directory (CEN) header compressed size field offset.
    See Also:

    field:CENLEN [NONE]

    CENLEN

    static final  int CENLEN
    Central directory (CEN) header uncompressed size field offset.
    See Also:

    field:CENNAM [NONE]

    CENNAM

    static final  int CENNAM
    Central directory (CEN) header filename length field offset.
    See Also:

    field:CENEXT [NONE]

    CENEXT

    static final  int CENEXT
    Central directory (CEN) header extra field length field offset.
    See Also:

    field:CENCOM [NONE]

    CENCOM

    static final  int CENCOM
    Central directory (CEN) header comment length field offset.
    See Also:

    field:CENDSK [NONE]

    CENDSK

    static final  int CENDSK
    Central directory (CEN) header disk number start field offset.
    See Also:

    field:CENATT [NONE]

    CENATT

    static final  int CENATT
    Central directory (CEN) header internal file attributes field offset.
    See Also:

    field:CENATX [NONE]

    CENATX

    static final  int CENATX
    Central directory (CEN) header external file attributes field offset.
    See Also:

    field:CENOFF [NONE]

    CENOFF

    static final  int CENOFF
    Central directory (CEN) header LOC header offset field offset.
    See Also:

    field:ENDSUB [NONE]

    ENDSUB

    static final  int ENDSUB
    End of central directory (END) header number of entries on this disk field offset.
    See Also:

    field:ENDTOT [NONE]

    ENDTOT

    static final  int ENDTOT
    End of central directory (END) header total number of entries field offset.
    See Also:

    field:ENDSIZ [NONE]

    ENDSIZ

    static final  int ENDSIZ
    End of central directory (END) header central directory size in bytes field offset.
    See Also:

    field:ENDOFF [NONE]

    ENDOFF

    static final  int ENDOFF
    End of central directory (END) header offset for the first CEN header field offset.
    See Also:

    field:ENDCOM [NONE]

    ENDCOM

    static final  int ENDCOM
    End of central directory (END) header zip file comment length field offset.
    See Also:

    constructor:ZipInputStream(java.io.InputStream) [NONE]

  • 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
  • constructor:ZipInputStream(java.io.InputStream,java.nio.charset.Charset) [NONE]

    ZipInputStream

    public ZipInputStream (InputStream in, Charset charset)
    Creates a new ZIP input stream.
    Parameters:
    in - the actual input stream
    charset - The charset to be used to decode the ZIP entry name (ignored if the language encoding bit of the ZIP entry's general purpose bit flag is set).
    Since:
    1.7

    method:getNextEntry() [NONE]

  • 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
  • method:closeEntry() [NONE]

    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

    method:available() [CHANGED]

    available

    public int available() throws IOException
    Returns 0 after EOFwhen end of stream is detected for the current ZIP entry or closeEntry() has reached forbeen called on the current ZIP entry data, otherwise always returnreturns 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 and0 after EOFwhen end of stream is detected for the current ZIP entry or closeEntry() has reached forbeen called on the current ZIP entry, otherwise 1.
    Throws:
    IOException - if an I/O error occurs.

    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.

    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.

    method:read() [ADDED]

    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:

    method:readAllBytes() [ADDED]

    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

    method:readNBytes(int) [ADDED]

    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

    method:readNBytes(byte[],int,int) [ADDED]

    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

    method:skipNBytes(long) [ADDED]

    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:

    method:transferTo(java.io.OutputStream) [ADDED]

    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 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

    method:read(byte[],int,int) [CHANGED]

    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 into an arrayreturning 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:

    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:

    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:

    method:skip(long) [CHANGED]

    skip

    public long skip (long n) throws IOException
    Skips specified numberover and discards n bytes of bytes indata 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:

    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
    See Also:

    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:

    method:close() [NONE]

    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:

    method:createZipEntry(java.lang.String) [NONE]

    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

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