Chapter 18
The java.util.zip Package

ZipInputStream

Name

ZipInputStream

Synopsis

Class Name:

java.util.zip.ZipInputStream

Superclass:

java.util.zip.InflaterInputStream

Immediate Subclasses:

None

Interfaces Implemented:

None

Availability:

New as of JDK 1.1

The ZipInputStream class reads files that have been compressed using the ZIP format. To read uncompressed data from a ZIP file, simply construct a ZipInputStream that wraps a regular input stream. The getNextEntry() method returns each entry in the ZIP file in order. Once you have a ZipEntry object, you use the read() method to retrieve uncompressed data from it. If you want to read the entries in a nonsequential order, use a ZipFile instead.

Class Summary

public class java.util.zip.ZipInputStream
             extends java.util.zip.InflaterInputStream {
  // Constructors
  public ZipInputStream(InputStream in);
  // Instance Methods
  public void close();
  public void closeEntry();
  public ZipEntry getNextEntry();
  public int read(byte[] b, int off, int len);
  public long skip(long n);
}

Constructors

ZipInputStream

public ZipInputStream(InputStream in)

Parameters

in: The underlying input stream.

Description

This constructor creates a ZipInputStream that inflates data from the given InputStream.

Instance Methods

close

public void close() throws IOException

Throws

IOException: If any I/O error occurs.

Overrides

FilterInputStream.close()

Description

This method closes this stream and releases any system resources that are associated with it.

closeEntry

public void closeEntry() throws IOException

Throws

ZipException

If a ZIP file format error occurs.

IOException

If any other kind of I/O error occurs.

Description

This method closes the currently open entry in the ZIP file. The stream is then positioned to read the next entry using getNextEntry().

getNextEntry

public ZipEntry getNextEntry() throws IOException

Returns

The ZipEntry for the next entry or null if there are no more entries.

Throws

ZipException

If a ZIP file format error occurs.

IOException

If any other kind of I/O error occurs.

Description

This method returns a ZipEntry that represents the next entry in the ZIP file and positions the stream to read that entry.

read

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

Parameters

b

An array of bytes to be filled from the stream.

off

An offset into the byte array.

len

The number of bytes to read.

Returns

The number of bytes read or -1 if the end of the entry is encountered immediately.

Throws

ZipException

If a ZIP file format error occurs.

IOException

If any other kind of I/O error occurs.

Overrides

InflaterInputStream.read(byte[], int, int)

Description

This method reads enough data from the underlying InputStream to return len bytes of uncompressed data. The uncompressed data is placed into the given array starting at off. The method blocks until some data is available for decompression.

skip

public long skip(long n) throws IOException

Returns

The actual number of bytes skipped.

Throws

ZipException

If a ZIP file format error occurs.

IOException

If any kind of I/O error occurs.

Overrides

InflaterInputStream.skip()

Description

This method skips over the specified number of uncompressed data bytes by reading data from the underlying InputStream and decompressing it.

Inherited Methods

Method	Inherited From	Method	Inherited From
`available()`	`FilterInputStream`	`clone()`	`Object`
`equals(Object)`	`Object`	`finalize()`	`Object`
`getClass()`	`Object`	`hashCode()`	`Object`
`mark(int)`	`FilterInputStream`	`markSupported()`	`FilterInputStream`
`notify()`	`Object`	`notifyAll()`	`Object`
`read()`	`InflaterInputStream`	`read(byte[])`	`FilterInputStream`
`reset()`	`FilterInputStream`	`toString()`	`Object`
`wait()`	`Object`	`wait(long)`	`Object`
`wait(long, int)`	`Object`