JarInputStream

public class JarInputStream
extends ZipInputStream

java.lang.Object
   ↳ java.io.InputStream
     ↳ java.io.FilterInputStream
       ↳ java.util.zip.InflaterInputStream
         ↳ java.util.zip.ZipInputStream
           ↳ java.util.jar.JarInputStream


The JarInputStream class is used to read the contents of a JAR file from any input stream. It extends the class java.util.zip.ZipInputStream with support for reading an optional Manifest entry. The Manifest can be used to store meta-information about the JAR file and its entries.

Summary

Constants

int CENATT

Central directory (CEN) header internal file attributes field offset.

int CENATX

Central directory (CEN) header external file attributes field offset.

int CENCOM

Central directory (CEN) header comment length field offset.

int CENCRC

Central directory (CEN) header uncompressed file crc-32 value field offset.

int CENDSK

Central directory (CEN) header disk number start field offset.

int CENEXT

Central directory (CEN) header extra field length field offset.

int CENFLG

Central directory (CEN) header encrypt, decrypt flags field offset.

int CENHDR

Central directory (CEN) header size in bytes (including signature).

int CENHOW

Central directory (CEN) header compression method field offset.

int CENLEN

Central directory (CEN) header uncompressed size field offset.

int CENNAM

Central directory (CEN) header filename length field offset.

int CENOFF

Central directory (CEN) header LOC header offset field offset.

long CENSIG

Central directory (CEN) header signature.

int CENSIZ

Central directory (CEN) header compressed size field offset.

int CENTIM

Central directory (CEN) header modification time field offset.

int CENVEM

Central directory (CEN) header version made by field offset.

int CENVER

Central directory (CEN) header version needed to extract field offset.

int ENDCOM

End of central directory (END) header zip file comment length field offset.

int ENDHDR

End of central directory (END) header size in bytes (including signature).

int ENDOFF

End of central directory (END) header offset for the first CEN header field offset.

long ENDSIG

End of central directory (END) header signature.

int ENDSIZ

End of central directory (END) header central directory size in bytes field offset.

int ENDSUB

End of central directory (END) header number of entries on this disk field offset.

int ENDTOT

End of central directory (END) header total number of entries field offset.

int EXTCRC

Extra local (EXT) header uncompressed file crc-32 value field offset.

int EXTHDR

Extra local (EXT) header size in bytes (including signature).

int EXTLEN

Extra local (EXT) header uncompressed size field offset.

long EXTSIG

Extra local (EXT) header signature.

int EXTSIZ

Extra local (EXT) header compressed size field offset.

int LOCCRC

Local file (LOC) header uncompressed file crc-32 value field offset.

int LOCEXT

Local file (LOC) header extra field length field offset.

int LOCFLG

Local file (LOC) header general purpose bit flag field offset.

int LOCHDR

Local file (LOC) header size in bytes (including signature).

int LOCHOW

Local file (LOC) header compression method field offset.

int LOCLEN

Local file (LOC) header uncompressed size field offset.

int LOCNAM

Local file (LOC) header filename length field offset.

long LOCSIG

Local file (LOC) header signature.

int LOCSIZ

Local file (LOC) header compressed size field offset.

int LOCTIM

Local file (LOC) header modification time field offset.

int LOCVER

Local file (LOC) header version needed to extract field offset.

Inherited constants

Inherited fields

Public constructors

JarInputStream(InputStream in)

Creates a new JarInputStream and reads the optional manifest.

JarInputStream(InputStream in, boolean verify)

Creates a new JarInputStream and reads the optional manifest.

Public methods

Manifest getManifest()

Returns the Manifest for this JAR file, or null if none.

ZipEntry getNextEntry()

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

JarEntry getNextJarEntry()

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

int read(byte[] b, int off, int len)

Reads from the current JAR file entry into an array of bytes.

Protected methods

ZipEntry createZipEntry(String name)

Creates a new JarEntry (ZipEntry) for the specified JAR file entry name.

Inherited methods

Constants

CENATT

Added in API level 21
public static final int CENATT

Central directory (CEN) header internal file attributes field offset.

Constant Value: 36 (0x00000024)

CENATX

Added in API level 21
public static final int CENATX

Central directory (CEN) header external file attributes field offset.

Constant Value: 38 (0x00000026)

CENCOM

Added in API level 21
public static final int CENCOM

Central directory (CEN) header comment length field offset.

Constant Value: 32 (0x00000020)

CENCRC

Added in API level 21
public static final int CENCRC

Central directory (CEN) header uncompressed file crc-32 value field offset.

Constant Value: 16 (0x00000010)

CENDSK

Added in API level 21
public static final int CENDSK

Central directory (CEN) header disk number start field offset.

Constant Value: 34 (0x00000022)

CENEXT

Added in API level 21
public static final int CENEXT

Central directory (CEN) header extra field length field offset.

Constant Value: 30 (0x0000001e)

CENFLG

Added in API level 21
public static final int CENFLG

Central directory (CEN) header encrypt, decrypt flags field offset.

Constant Value: 8 (0x00000008)

CENHDR

Added in API level 21
public static final int CENHDR

Central directory (CEN) header size in bytes (including signature).

Constant Value: 46 (0x0000002e)

CENHOW

Added in API level 21
public static final int CENHOW

Central directory (CEN) header compression method field offset.

Constant Value: 10 (0x0000000a)

CENLEN

Added in API level 21
public static final int CENLEN

Central directory (CEN) header uncompressed size field offset.

Constant Value: 24 (0x00000018)

CENNAM

Added in API level 21
public static final int CENNAM

Central directory (CEN) header filename length field offset.

Constant Value: 28 (0x0000001c)

CENOFF

Added in API level 21
public static final int CENOFF

Central directory (CEN) header LOC header offset field offset.

Constant Value: 42 (0x0000002a)

CENSIG

Added in API level 21
public static final long CENSIG

Central directory (CEN) header signature.

Constant Value: 33639248 (0x0000000002014b50)

CENSIZ

Added in API level 21
public static final int CENSIZ

Central directory (CEN) header compressed size field offset.

Constant Value: 20 (0x00000014)

CENTIM

Added in API level 21
public static final int CENTIM

Central directory (CEN) header modification time field offset.

Constant Value: 12 (0x0000000c)

CENVEM

Added in API level 21
public static final int CENVEM

Central directory (CEN) header version made by field offset.

Constant Value: 4 (0x00000004)

CENVER

Added in API level 21
public static final int CENVER

Central directory (CEN) header version needed to extract field offset.

Constant Value: 6 (0x00000006)

ENDCOM

Added in API level 21
public static final int ENDCOM

End of central directory (END) header zip file comment length field offset.

Constant Value: 20 (0x00000014)

ENDHDR

Added in API level 21
public static final int ENDHDR

End of central directory (END) header size in bytes (including signature).

Constant Value: 22 (0x00000016)

ENDOFF

Added in API level 21
public static final int ENDOFF

End of central directory (END) header offset for the first CEN header field offset.

Constant Value: 16 (0x00000010)

ENDSIG

Added in API level 21
public static final long ENDSIG

End of central directory (END) header signature.

Constant Value: 101010256 (0x0000000006054b50)

ENDSIZ

Added in API level 21
public static final int ENDSIZ

End of central directory (END) header central directory size in bytes field offset.

Constant Value: 12 (0x0000000c)

ENDSUB

Added in API level 21
public static final int ENDSUB

End of central directory (END) header number of entries on this disk field offset.

Constant Value: 8 (0x00000008)

ENDTOT

Added in API level 21
public static final int ENDTOT

End of central directory (END) header total number of entries field offset.

Constant Value: 10 (0x0000000a)

EXTCRC

Added in API level 21
public static final int EXTCRC

Extra local (EXT) header uncompressed file crc-32 value field offset.

Constant Value: 4 (0x00000004)

EXTHDR

Added in API level 21
public static final int EXTHDR

Extra local (EXT) header size in bytes (including signature).

Constant Value: 16 (0x00000010)

EXTLEN

Added in API level 21
public static final int EXTLEN

Extra local (EXT) header uncompressed size field offset.

Constant Value: 12 (0x0000000c)

EXTSIG

Added in API level 21
public static final long EXTSIG

Extra local (EXT) header signature.

Constant Value: 134695760 (0x0000000008074b50)

EXTSIZ

Added in API level 21
public static final int EXTSIZ

Extra local (EXT) header compressed size field offset.

Constant Value: 8 (0x00000008)

LOCCRC

Added in API level 21
public static final int LOCCRC

Local file (LOC) header uncompressed file crc-32 value field offset.

Constant Value: 14 (0x0000000e)

LOCEXT

Added in API level 21
public static final int LOCEXT

Local file (LOC) header extra field length field offset.

Constant Value: 28 (0x0000001c)

LOCFLG

Added in API level 21
public static final int LOCFLG

Local file (LOC) header general purpose bit flag field offset.

Constant Value: 6 (0x00000006)

LOCHDR

Added in API level 21
public static final int LOCHDR

Local file (LOC) header size in bytes (including signature).

Constant Value: 30 (0x0000001e)

LOCHOW

Added in API level 21
public static final int LOCHOW

Local file (LOC) header compression method field offset.

Constant Value: 8 (0x00000008)

LOCLEN

Added in API level 21
public static final int LOCLEN

Local file (LOC) header uncompressed size field offset.

Constant Value: 22 (0x00000016)

LOCNAM

Added in API level 21
public static final int LOCNAM

Local file (LOC) header filename length field offset.

Constant Value: 26 (0x0000001a)

LOCSIG

Added in API level 21
public static final long LOCSIG

Local file (LOC) header signature.

Constant Value: 67324752 (0x0000000004034b50)

LOCSIZ

Added in API level 21
public static final int LOCSIZ

Local file (LOC) header compressed size field offset.

Constant Value: 18 (0x00000012)

LOCTIM

Added in API level 21
public static final int LOCTIM

Local file (LOC) header modification time field offset.

Constant Value: 10 (0x0000000a)

LOCVER

Added in API level 21
public static final int LOCVER

Local file (LOC) header version needed to extract field offset.

Constant Value: 4 (0x00000004)

Public constructors

JarInputStream

Added in API level 1
public JarInputStream (InputStream in)

Creates a new JarInputStream and reads the optional manifest. If a manifest is present, also attempts to verify the signatures if the JarInputStream is signed.

Parameters
in InputStream: the actual input stream

Throws
IOException if an I/O error has occurred

JarInputStream

Added in API level 1
public JarInputStream (InputStream in, 
                boolean verify)

Creates a new JarInputStream and reads the optional manifest. If a manifest is present and verify is true, also attempts to verify the signatures if the JarInputStream is signed.

Parameters
in InputStream: the actual input stream

verify boolean: whether or not to verify the JarInputStream if it is signed.

Throws
IOException if an I/O error has occurred

Public methods

getManifest

Added in API level 1
public Manifest getManifest ()

Returns the Manifest for this JAR file, or null if none.

Returns
Manifest the Manifest for this JAR file, or null if none.

getNextEntry

Added in API level 1
public ZipEntry getNextEntry ()

Reads the next ZIP file entry and positions the stream at the beginning of the entry data. If verification has been enabled, any invalid signature detected while positioning the stream for the next entry will result in an exception.

Returns
ZipEntry 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
SecurityException if any of the jar file entries are incorrectly signed.

getNextJarEntry

Added in API level 1
public JarEntry getNextJarEntry ()

Reads the next JAR file entry and positions the stream at the beginning of the entry data. If verification has been enabled, any invalid signature detected while positioning the stream for the next entry will result in an exception.

Returns
JarEntry the next JAR 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
SecurityException if any of the jar file entries are incorrectly signed.

read

Added in API level 1
public int read (byte[] b, 
                int off, 
                int len)

Reads from the current JAR file 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. If verification has been enabled, any invalid signature on the current entry will be reported at some point before the end of the entry is reached.

Parameters
b byte: the buffer into which the data is read

off int: the start offset in the destination array b

len int: the maximum number of bytes to read

Returns
int 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
SecurityException if any of the jar file entries are incorrectly signed.

Protected methods

createZipEntry

Added in API level 1
protected ZipEntry createZipEntry (String name)

Creates a new JarEntry (ZipEntry) for the specified JAR file entry name. The manifest attributes of the specified JAR file entry name will be copied to the new JarEntry.

Parameters
name String: the name of the JAR/ZIP file entry

Returns
ZipEntry the JarEntry object just created