java.util.jar
Class JarInputStream

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

All Implemented Interfaces:

Closeable

public class JarInputStream
extends ZipInputStream

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.

Since:

1.2

See Also:

Manifest, ZipInputStream

Field Summary
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	LOCHDR
static int	LOCHOW
static int	LOCLEN
static int	LOCNAM
static long	LOCSIG
static int	LOCSIZ
static int	LOCTIM
static int	LOCVER

 

Fields inherited from class java.util.zip.InflaterInputStream
buf, inf, len

 

Fields inherited from class java.io.FilterInputStream
in

 

Constructor Summary
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.

 

Method Summary
protected  ZipEntry	createZipEntry(String name)           Creates a new JarEntry (ZipEntry) for the specified JAR file entry name.
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.

 

Methods inherited from class java.util.zip.ZipInputStream
available, close, closeEntry, skip

 

Methods inherited from class java.util.zip.InflaterInputStream
fill, mark, markSupported, read, reset

 

Methods inherited from class java.io.FilterInputStream
read

 

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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CENSIG

public static final long CENSIG

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ENDSIG

public static final long ENDSIG

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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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JarInputStream

public JarInputStream(InputStream in)
               throws IOException

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 - the actual input stream

Throws:

IOException - if an I/O error has occurred

JarInputStream

public JarInputStream(InputStream in,
                      boolean verify)
               throws IOException

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 - the actual input stream

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

Throws:

IOException - if an I/O error has occurred

getManifest

public Manifest getManifest()

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

Returns:

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

getNextEntry

public ZipEntry getNextEntry()
                      throws IOException

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.

Overrides:

getNextEntry in class ZipInputStream

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

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

getNextJarEntry

public JarEntry getNextJarEntry()
                         throws IOException

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:

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

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

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.

Overrides:

read in class ZipInputStream

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 to 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

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

See Also:

FilterInputStream.in

createZipEntry

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.

Overrides:

createZipEntry in class ZipInputStream

Parameters:

name - the name of the JAR/ZIP file entry

Returns:

the JarEntry object just created