Closeable
, AutoCloseable
JarInputStream
public class ZipInputStream extends InflaterInputStream
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);
}
}
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.Modifier and Type | Field | Description |
---|---|---|
static final int |
CENATT |
Central directory (CEN) header internal file attributes field offset. |
static final int |
CENATX |
Central directory (CEN) header external file attributes field offset. |
static final int |
CENCOM |
Central directory (CEN) header comment length field offset. |
static final int |
CENCRC |
Central directory (CEN) header uncompressed file crc-32 value field offset. |
static final int |
CENDSK |
Central directory (CEN) header disk number start field offset. |
static final int |
CENEXT |
Central directory (CEN) header extra field length field offset. |
static final int |
CENFLG |
Central directory (CEN) header encrypt, decrypt flags field offset. |
static final int |
CENHDR |
Central directory (CEN) header size in bytes (including signature). |
static final int |
CENHOW |
Central directory (CEN) header compression method field offset. |
static final int |
CENLEN |
Central directory (CEN) header uncompressed size field offset. |
static final int |
CENNAM |
Central directory (CEN) header filename length field offset. |
static final int |
CENOFF |
Central directory (CEN) header LOC header offset field offset. |
static final long |
CENSIG |
Central directory (CEN) header signature. |
static final int |
CENSIZ |
Central directory (CEN) header compressed size field offset. |
static final int |
CENTIM |
Central directory (CEN) header modification time field offset. |
static final int |
CENVEM |
Central directory (CEN) header version made by field offset. |
static final int |
CENVER |
Central directory (CEN) header version needed to extract field offset. |
static final int |
ENDCOM |
End of central directory (END) header zip file comment length field offset. |
static final int |
ENDHDR |
End of central directory (END) header size in bytes (including signature). |
static final int |
ENDOFF |
End of central directory (END) header offset for the first CEN header field offset. |
static final long |
ENDSIG |
End of central directory (END) header signature. |
static final int |
ENDSIZ |
End of central directory (END) header central directory size in bytes field offset. |
static final int |
ENDSUB |
End of central directory (END) header number of entries on this disk field offset. |
static final int |
ENDTOT |
End of central directory (END) header total number of entries field offset. |
static final int |
EXTCRC |
Extra local (EXT) header uncompressed file crc-32 value field offset. |
static final int |
EXTHDR |
Extra local (EXT) header size in bytes (including signature). |
static final int |
EXTLEN |
Extra local (EXT) header uncompressed size field offset. |
static final long |
EXTSIG |
Extra local (EXT) header signature. |
static final int |
EXTSIZ |
Extra local (EXT) header compressed size field offset. |
static final int |
LOCCRC |
Local file (LOC) header uncompressed file crc-32 value field offset. |
static final int |
LOCEXT |
Local file (LOC) header extra field length field offset. |
static final int |
LOCFLG |
Local file (LOC) header general purpose bit flag field offset. |
static final int |
LOCHDR |
Local file (LOC) header size in bytes (including signature). |
static final int |
LOCHOW |
Local file (LOC) header compression method field offset. |
static final int |
LOCLEN |
Local file (LOC) header uncompressed size field offset. |
static final int |
LOCNAM |
Local file (LOC) header filename length field offset. |
static final long |
LOCSIG |
Local file (LOC) header signature. |
static final int |
LOCSIZ |
Local file (LOC) header compressed size field offset. |
static final int |
LOCTIM |
Local file (LOC) header modification time field offset. |
static final int |
LOCVER |
Local file (LOC) header version needed to extract field offset. |
buf, inf, len
in
Constructor | Description |
---|---|
ZipInputStream |
Creates a new ZIP input stream. |
ZipInputStream |
Creates a new ZIP input stream. |
Modifier and Type | Method | Description |
---|---|---|
int |
available() |
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. |
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 |
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. |
int |
read() |
Reads the next byte of data from the input stream for the current ZIP entry. |
int |
read |
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. |
byte[] |
readAllBytes() |
Reads all remaining bytes from the input stream for the current ZIP entry. |
int |
readNBytes |
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. |
byte[] |
readNBytes |
Reads up to a specified number of bytes from the input stream for the current ZIP entry. |
long |
skip |
Skips over and discards n bytes of data from this input stream for the current ZIP entry. |
void |
skipNBytes |
Skips over and discards exactly n bytes of data from this input stream for the current ZIP entry. |
long |
transferTo |
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. |
fill, mark, markSupported, reset
read
nullInputStream
static final long LOCSIG
static final long EXTSIG
static final long CENSIG
static final long ENDSIG
static final int LOCHDR
static final int EXTHDR
static final int CENHDR
static final int ENDHDR
static final int LOCVER
static final int LOCFLG
static final int LOCHOW
static final int LOCTIM
static final int LOCCRC
static final int LOCSIZ
static final int LOCLEN
static final int LOCNAM
static final int LOCEXT
static final int EXTCRC
static final int EXTSIZ
static final int EXTLEN
static final int CENVEM
static final int CENVER
static final int CENFLG
static final int CENHOW
static final int CENTIM
static final int CENCRC
static final int CENSIZ
static final int CENLEN
static final int CENNAM
static final int CENEXT
static final int CENCOM
static final int CENDSK
static final int CENATT
static final int CENATX
static final int CENOFF
static final int ENDSUB
static final int ENDTOT
static final int ENDSIZ
static final int ENDOFF
static final int ENDCOM
public ZipInputStream(InputStream in)
The UTF-8 charset
is used to decode the entry names.
in
- the actual input streampublic ZipInputStream(InputStream in, Charset charset)
in
- the actual input streamcharset
- 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).public ZipEntry getNextEntry() throws IOException
ZipException
- if a ZIP file error has occurredIOException
- if an I/O error has occurredpublic void closeEntry() throws IOException
ZipException
- if a ZIP file error has occurredIOException
- if an I/O error has occurredpublic int available() throws IOException
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.
available
in class InflaterInputStream
closeEntry()
has been called on the current ZIP entry, otherwise 1.IOException
- if an I/O error occurs.public int read() throws IOException
read
in class InflaterInputStream
IOException
- if an I/O error has occurredpublic byte[] readAllBytes() throws IOException
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.
readAllBytes
in class InputStream
OutOfMemoryError
- if an array of the required size cannot be allocated.IOException
- if an I/O error occurspublic byte[] readNBytes(int len) throws IOException
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.
readNBytes
in class InputStream
super.readNBytes(int len)
.len
- the maximum number of bytes to readOutOfMemoryError
- if an array of the required size cannot be allocated.IOException
- if an I/O error occurspublic int readNBytes(byte[] b, int off, int len) throws IOException
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.
readNBytes
in class InputStream
b
- the byte array into which the data is readoff
- the start offset in b
at which the data is writtenlen
- the maximum number of bytes to readNullPointerException
- 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 occurspublic void skipNBytes(long n) throws IOException
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.
skipNBytes
in class InputStream
n
- the number of bytes to be skipped.IOException
- if the stream cannot be positioned properly or if an I/O error occurs.public long transferTo(OutputStream out) throws IOException
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.
transferTo
in class InputStream
out
- the output stream, non-nullNullPointerException
- if out
is null
IOException
- if an I/O error occurs when reading or writingpublic int read(byte[] b, int off, int len) throws IOException
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.
read
in class InflaterInputStream
b
- the buffer into which the data is readoff
- the start offset in the destination array b
len
- the maximum number of bytes readNullPointerException
- 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 occurredIOException
- if an I/O error has occurredpublic long skip(long n) throws IOException
n
bytes of data from this input stream for the current ZIP entry.skip
in class InflaterInputStream
n
- the number of bytes to skipZipException
- if a ZIP file error has occurredIOException
- if an I/O error has occurredIllegalArgumentException
- if n < 0
public void close() throws IOException
close
in interface AutoCloseable
close
in interface Closeable
close
in class InflaterInputStream
IOException
- if an I/O error has occurredprotected ZipEntry createZipEntry(String name)
ZipEntry
object for the specified entry name.name
- the ZIP file entry name
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.base/java/util/zip/ZipInputStream.html