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JarInputStream (Java Platform SE 6) - JDK 5 Documentation v6.0, Java 2 SDK 英文文档

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Java™ Platform
Standard Ed. 6
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java.util.jar
Class JarInputStream

java.lang.Object
  extended by java.io.InputStream
      extended by java.io.FilterInputStream
          extended by java.util.zip.InflaterInputStream
              extended by java.util.zip.ZipInputStream
                  extended by 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
See Also:
Constant Field Values

EXTSIG

public static final long EXTSIG
See Also:
Constant Field Values

CENSIG

public static final long CENSIG
See Also:
Constant Field Values

ENDSIG

public static final long ENDSIG
See Also:
Constant Field Values

LOCHDR

public static final int LOCHDR
See Also:
Constant Field Values

EXTHDR

public static final int EXTHDR
See Also:
Constant Field Values

CENHDR

public static final int CENHDR
See Also:
Constant Field Values

ENDHDR

public static final int ENDHDR
See Also:
Constant Field Values

LOCVER

public static final int LOCVER
See Also:
Constant Field Values

LOCFLG

public static final int LOCFLG
See Also:
Constant Field Values

LOCHOW

public static final int LOCHOW
See Also:
Constant Field Values

LOCTIM

public static final int LOCTIM
See Also:
Constant Field Values

LOCCRC

public static final int LOCCRC
See Also:
Constant Field Values

LOCSIZ

public static final int LOCSIZ
See Also:
Constant Field Values

LOCLEN

public static final int LOCLEN
See Also:
Constant Field Values

LOCNAM

public static final int LOCNAM
See Also:
Constant Field Values

LOCEXT

public static final int LOCEXT
See Also:
Constant Field Values

EXTCRC

public static final int EXTCRC
See Also:
Constant Field Values

EXTSIZ

public static final int EXTSIZ
See Also:
Constant Field Values

EXTLEN

public static final int EXTLEN
See Also:
Constant Field Values

CENVEM

public static final int CENVEM
See Also:
Constant Field Values

CENVER

public static final int CENVER
See Also:
Constant Field Values

CENFLG

public static final int CENFLG
See Also:
Constant Field Values

CENHOW

public static final int CENHOW
See Also:
Constant Field Values

CENTIM

public static final int CENTIM
See Also:
Constant Field Values

CENCRC

public static final int CENCRC
See Also:
Constant Field Values

CENSIZ

public static final int CENSIZ
See Also:
Constant Field Values

CENLEN

public static final int CENLEN
See Also:
Constant Field Values

CENNAM

public static final int CENNAM
See Also:
Constant Field Values

CENEXT

public static final int CENEXT
See Also:
Constant Field Values

CENCOM

public static final int CENCOM
See Also:
Constant Field Values

CENDSK

public static final int CENDSK
See Also:
Constant Field Values

CENATT

public static final int CENATT
See Also:
Constant Field Values

CENATX

public static final int CENATX
See Also:
Constant Field Values

CENOFF

public static final int CENOFF
See Also:
Constant Field Values

ENDSUB

public static final int ENDSUB
See Also:
Constant Field Values

ENDTOT

public static final int ENDTOT
See Also:
Constant Field Values

ENDSIZ

public static final int ENDSIZ
See Also:
Constant Field Values

ENDOFF

public static final int ENDOFF
See Also:
Constant Field Values

ENDCOM

public static final int ENDCOM
See Also:
Constant Field Values
Constructor Detail

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
Method Detail

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
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Java™ Platform
Standard Ed. 6
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For further API reference and developer documentation, see Java SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2006 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.