Module java.base
Package 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, AutoCloseable
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 Details

  • Constructor Details

    • 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 Details

    • 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