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, ZipConstants

Most common way to construct:

InputStream in = …;

JarInputStream jis = new JarInputStream(in);

Based on 18 examples

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.

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

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

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

Throws:

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. 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:

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. 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:

IOException - if an I/O error has occurred