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Java 2 Platform SE v1.3.1: Class JarInputStream - JDK 5 Documentation v1.3.1, Java 2 SDK 英文文档

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JavaTM 2 Platform
Std. Ed. v1.3.1
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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:
java.util.zip.ZipConstants
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

Fields inherited from class java.util.zip.ZipInputStream
CENATT, CENATX, CENCOM, CENCRC, CENDSK, CENEXT, CENFLG, CENHDR, CENHOW, CENLEN, CENNAM, CENOFF, CENSIG, CENSIZ, CENTIM, CENVEM, CENVER, ENDCOM, ENDHDR, ENDOFF, ENDSIG, ENDSIZ, ENDSUB, ENDTOT, EXTCRC, EXTHDR, EXTLEN, EXTSIG, EXTSIZ, LOCCRC, LOCEXT, LOCFLG, LOCHDR, LOCHOW, LOCLEN, LOCNAM, LOCSIG, LOCSIZ, LOCTIM, 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 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, read
 
Methods inherited from class java.io.FilterInputStream
mark, markSupported, read, reset
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

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 stream at the beginning of the entry data.
Overrides:
getNextEntry in class ZipInputStream
Throws:
ZipException - if a ZIP file error has occurred
IOException - if an I/O error has occurred

getNextJarEntry

public JarEntry getNextJarEntry()
                         throws IOException
Reads the next JAR file entry and positions the stream at the beginning of the entry data.
Returns:
the next JAR file entry
Throws:
ZipException - if a ZIP file error has occurred
IOException - if an I/O error has occurred

read

public int read(byte[] b,
                int off,
                int len)
         throws IOException
Reads from the current JAR file entry into an array of bytes. Blocks until some input is available.
Overrides:
read in class ZipInputStream
Parameters:
b - the buffer into which the data is read
off - the start offset of the data
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:
ZipException - if a ZIP file error has occurred
IOException - if an I/O error has occurred

createZipEntry

protected ZipEntry createZipEntry(String name)
Creates a new JarEntry (ZipEntry) for the specified JAR file entry name.
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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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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