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org.apache.commons.compress.archivers.zip
Class ZipArchiveOutputStream

java.lang.Object
  extended by java.io.OutputStream
      extended by org.apache.commons.compress.archivers.ArchiveOutputStream
          extended by org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream
All Implemented Interfaces:
Closeable, Flushable
Direct Known Subclasses:
JarArchiveOutputStream
public class ZipArchiveOutputStream
extends ArchiveOutputStream

Reimplementation of java.util.zip.ZipOutputStream that does handle the extended functionality of this package, especially internal/external file attributes and extra fields with different layouts for local file data and central directory entries.

This class will try to use RandomAccessFile when you know that the output is going to go to a file.

If RandomAccessFile cannot be used, this implementation will use a Data Descriptor to store size and CRC information for DEFLATED entries, this means, you don't need to calculate them yourself. Unfortunately this is not possible for the STORED method, here setting the CRC and uncompressed size information is required before putArchiveEntry(ArchiveEntry) can be called.

As of Apache Commons Compress 1.3 it transparently supports Zip64 extensions and thus individual entries and archives larger than 4 GB or with more than 65536 entries in most cases but explicit control is provided via setUseZip64(org.apache.commons.compress.archivers.zip.Zip64Mode). If the stream can not user RandomAccessFile and you try to write a ZipArchiveEntry of unknown size then Zip64 extensions will be disabled by default.

Nested Class Summary
static class ZipArchiveOutputStream.UnicodeExtraFieldPolicy
          enum that represents the possible policies for creating Unicode extra fields.
 
Field Summary
protected  Deflater def
          This Deflater object is used for output.
static int DEFAULT_COMPRESSION
          Default compression level for deflated entries.
static int DEFLATED
          Compression method for deflated entries.
static int EFS_FLAG
          Deprecated. use GeneralPurposeBit.UFT8_NAMES_FLAG instead
protected  boolean finished
          indicates if this archive is finished. protected for use in Jar implementation
static int STORED
          Compression method for stored entries.
 
Constructor Summary
ZipArchiveOutputStream(File file)
          Creates a new ZIP OutputStream writing to a File.
ZipArchiveOutputStream(OutputStream out)
          Creates a new ZIP OutputStream filtering the underlying stream.
 
Method Summary
 boolean canWriteEntryData(ArchiveEntry ae)
          Whether this stream is able to write the given entry.
 void close()
          Closes this output stream and releases any system resources associated with the stream.
 void closeArchiveEntry()
          Writes all necessary data for this entry.
 ArchiveEntry createArchiveEntry(File inputFile, String entryName)
          Creates a new zip entry taking some information from the given file and using the provided name.
protected  void deflate()
          Writes next block of compressed data to the output stream.
 void finish()
          Finishes the addition of entries to this stream, without closing it.
 void flush()
          Flushes this output stream and forces any buffered output bytes to be written out to the stream.
 String getEncoding()
          The encoding to use for filenames and the file comment.
 boolean isSeekable()
          This method indicates whether this archive is writing to a seekable stream (i.e., to a random access file).
 void putArchiveEntry(ArchiveEntry archiveEntry)
          Writes the headers for an archive entry to the output stream.
 void setComment(String comment)
          Set the file comment.
 void setCreateUnicodeExtraFields(ZipArchiveOutputStream.UnicodeExtraFieldPolicy b)
          Whether to create Unicode Extra Fields.
 void setEncoding(String encoding)
          The encoding to use for filenames and the file comment.
 void setFallbackToUTF8(boolean b)
          Whether to fall back to UTF and the language encoding flag if the file name cannot be encoded using the specified encoding.
 void setLevel(int level)
          Sets the compression level for subsequent entries.
 void setMethod(int method)
          Sets the default compression method for subsequent entries.
 void setUseLanguageEncodingFlag(boolean b)
          Whether to set the language encoding flag if the file name encoding is UTF-8.
 void setUseZip64(Zip64Mode mode)
          Whether Zip64 extensions will be used.
 void write(byte[] b, int offset, int length)
          Writes bytes to ZIP entry.
protected  void writeCentralDirectoryEnd()
          Writes the "End of central dir record".
protected  void writeCentralFileHeader(ZipArchiveEntry ze)
          Writes the central file header entry.
protected  void writeDataDescriptor(ZipArchiveEntry ze)
          Writes the data descriptor entry.
protected  void writeLocalFileHeader(ZipArchiveEntry ze)
          Writes the local file header entry
protected  void writeOut(byte[] data)
          Write bytes to output or random access file.
protected  void writeOut(byte[] data, int offset, int length)
          Write bytes to output or random access file.
protected  void writeZip64CentralDirectory()
          Writes the "ZIP64 End of central dir record" and "ZIP64 End of central dir locator".
 
Methods inherited from class org.apache.commons.compress.archivers.ArchiveOutputStream
count, count, getBytesWritten, getCount, write
 
Methods inherited from class java.io.OutputStream
write
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

finished

protected boolean finished
indicates if this archive is finished. protected for use in Jar implementation

DEFLATED

public static final int DEFLATED
Compression method for deflated entries.

See Also:
Constant Field Values

DEFAULT_COMPRESSION

public static final int DEFAULT_COMPRESSION
Default compression level for deflated entries.

See Also:
Constant Field Values

STORED

public static final int STORED
Compression method for stored entries.

See Also:
Constant Field Values

EFS_FLAG

@Deprecated
public static final int EFS_FLAG
Deprecated. use GeneralPurposeBit.UFT8_NAMES_FLAG instead
General purpose flag, which indicates that filenames are written in utf-8.

See Also:
Constant Field Values

def

protected final Deflater def
This Deflater object is used for output.

Constructor Detail

ZipArchiveOutputStream

public ZipArchiveOutputStream(OutputStream out)
Creates a new ZIP OutputStream filtering the underlying stream.

Parameters:
out - the outputstream to zip

ZipArchiveOutputStream

public ZipArchiveOutputStream(File file)
                       throws IOException
Creates a new ZIP OutputStream writing to a File. Will use random access if possible.

Parameters:
file - the file to zip to
Throws:
IOException - on error
Method Detail

isSeekable

public boolean isSeekable()
This method indicates whether this archive is writing to a seekable stream (i.e., to a random access file).

For seekable streams, you don't need to calculate the CRC or uncompressed size for STORED entries before invoking putArchiveEntry(ArchiveEntry).

Returns:
true if seekable

setEncoding

public void setEncoding(String encoding)
The encoding to use for filenames and the file comment.

For a list of possible values see http://java.sun.com/j2se/1.5.0/docs/guide/intl/encoding.doc.html. Defaults to UTF-8.

Parameters:
encoding - the encoding to use for file names, use null for the platform's default encoding

getEncoding

public String getEncoding()
The encoding to use for filenames and the file comment.

Returns:
null if using the platform's default character encoding.

setUseLanguageEncodingFlag

public void setUseLanguageEncodingFlag(boolean b)
Whether to set the language encoding flag if the file name encoding is UTF-8.

Defaults to true.

setCreateUnicodeExtraFields

public void setCreateUnicodeExtraFields(ZipArchiveOutputStream.UnicodeExtraFieldPolicy b)
Whether to create Unicode Extra Fields.

Defaults to NEVER.

setFallbackToUTF8

public void setFallbackToUTF8(boolean b)
Whether to fall back to UTF and the language encoding flag if the file name cannot be encoded using the specified encoding.

Defaults to false.

setUseZip64

public void setUseZip64(Zip64Mode mode)
Whether Zip64 extensions will be used.

When setting the mode to Never, putArchiveEntry(org.apache.commons.compress.archivers.ArchiveEntry), closeArchiveEntry(), finish() or close() may throw a Zip64RequiredException if the entry's size or the total size of the archive exceeds 4GB or there are more than 65536 entries inside the archive. Any archive created in this mode will be readable by implementations that don't support Zip64.

When setting the mode to Always, Zip64 extensions will be used for all entries. Any archive created in this mode may be unreadable by implementations that don't support Zip64 even if all its contents would be.

When setting the mode to AsNeeded, Zip64 extensions will transparently be used for those entries that require them. This mode can only be used if the uncompressed size of the ZipArchiveEntry is known when calling putArchiveEntry(org.apache.commons.compress.archivers.ArchiveEntry) or the archive is written to a seekable output (i.e. you have used the File-arg constructor) - this mode is not valid when the output stream is not seekable and the uncompressed size is unknown when putArchiveEntry(org.apache.commons.compress.archivers.ArchiveEntry) is called.

If no entry inside the resulting archive requires Zip64 extensions then Never will create the smallest archive. AsNeeded will create a slightly bigger archive if the uncompressed size of any entry has initially been unknown and create an archive identical to Never otherwise. Always will create an archive that is at least 24 bytes per entry bigger than the one Never would create.

Defaults to AsNeeded unless putArchiveEntry(org.apache.commons.compress.archivers.ArchiveEntry) is called with an entry of unknown size and data is written to a non-seekable stream - in this case the default is Never.

Since:
1.3

finish

public void finish()
            throws IOException
Finishes the addition of entries to this stream, without closing it. Additional data can be written, if the format supports it. The finish() method throws an Exception if the user forgets to close the entry .

Specified by:
finish in class ArchiveOutputStream
Throws:
Zip64RequiredException - if the archive's size exceeds 4 GByte or there are more than 65535 entries inside the archive and setUseZip64(org.apache.commons.compress.archivers.zip.Zip64Mode) is Zip64Mode.Never.
IOException

closeArchiveEntry

public void closeArchiveEntry()
                       throws IOException
Writes all necessary data for this entry.

Specified by:
closeArchiveEntry in class ArchiveOutputStream
Throws:
IOException - on error
Zip64RequiredException - if the entry's uncompressed or compressed size exceeds 4 GByte and setUseZip64(org.apache.commons.compress.archivers.zip.Zip64Mode) is Zip64Mode.Never.

putArchiveEntry

public void putArchiveEntry(ArchiveEntry archiveEntry)
                     throws IOException
Writes the headers for an archive entry to the output stream. The caller must then write the content to the stream and call ArchiveOutputStream.closeArchiveEntry() to complete the process.

Specified by:
putArchiveEntry in class ArchiveOutputStream
Parameters:
archiveEntry - describes the entry
Throws:
ClassCastException - if entry is not an instance of ZipArchiveEntry
Zip64RequiredException - if the entry's uncompressed or compressed size is known to exceed 4 GByte and setUseZip64(org.apache.commons.compress.archivers.zip.Zip64Mode) is Zip64Mode.Never.
IOException

setComment

public void setComment(String comment)
Set the file comment.

Parameters:
comment - the comment

setLevel

public void setLevel(int level)
Sets the compression level for subsequent entries.

Default is Deflater.DEFAULT_COMPRESSION.

Parameters:
level - the compression level.
Throws:
IllegalArgumentException - if an invalid compression level is specified.

setMethod

public void setMethod(int method)
Sets the default compression method for subsequent entries.

Default is DEFLATED.

Parameters:
method - an int from java.util.zip.ZipEntry

canWriteEntryData

public boolean canWriteEntryData(ArchiveEntry ae)
Whether this stream is able to write the given entry.

May return false if it is set up to use encryption or a compression method that hasn't been implemented yet.

Overrides:
canWriteEntryData in class ArchiveOutputStream
Since:
1.1

write

public void write(byte[] b,
                  int offset,
                  int length)
           throws IOException
Writes bytes to ZIP entry.

Overrides:
write in class OutputStream
Parameters:
b - the byte array to write
offset - the start position to write from
length - the number of bytes to write
Throws:
IOException - on error

close

public void close()
           throws IOException
Closes this output stream and releases any system resources associated with the stream.

Specified by:
close in interface Closeable
Overrides:
close in class OutputStream
Throws:
IOException - if an I/O error occurs.
Zip64RequiredException - if the archive's size exceeds 4 GByte or there are more than 65535 entries inside the archive and setUseZip64(org.apache.commons.compress.archivers.zip.Zip64Mode) is Zip64Mode.Never.

flush

public void flush()
           throws IOException
Flushes this output stream and forces any buffered output bytes to be written out to the stream.

Specified by:
flush in interface Flushable
Overrides:
flush in class OutputStream
Throws:
IOException - if an I/O error occurs.

deflate

protected final void deflate()
                      throws IOException
Writes next block of compressed data to the output stream.

Throws:
IOException - on error

writeLocalFileHeader

protected void writeLocalFileHeader(ZipArchiveEntry ze)
                             throws IOException
Writes the local file header entry

Parameters:
ze - the entry to write
Throws:
IOException - on error

writeDataDescriptor

protected void writeDataDescriptor(ZipArchiveEntry ze)
                            throws IOException
Writes the data descriptor entry.

Parameters:
ze - the entry to write
Throws:
IOException - on error

writeCentralFileHeader

protected void writeCentralFileHeader(ZipArchiveEntry ze)
                               throws IOException
Writes the central file header entry.

Parameters:
ze - the entry to write
Throws:
IOException - on error
Zip64RequiredException - if the archive's size exceeds 4 GByte and #setUseZip64 is Zip64Mode.Never.

writeCentralDirectoryEnd

protected void writeCentralDirectoryEnd()
                                 throws IOException
Writes the "End of central dir record".

Throws:
IOException - on error
Zip64RequiredException - if the archive's size exceeds 4 GByte or there are more than 65535 entries inside the archive and #setUseZip64 is Zip64Mode.Never.

writeZip64CentralDirectory

protected void writeZip64CentralDirectory()
                                   throws IOException
Writes the "ZIP64 End of central dir record" and "ZIP64 End of central dir locator".

Throws:
IOException - on error
Since:
1.3

writeOut

protected final void writeOut(byte[] data)
                       throws IOException
Write bytes to output or random access file.

Parameters:
data - the byte array to write
Throws:
IOException - on error

writeOut

protected final void writeOut(byte[] data,
                              int offset,
                              int length)
                       throws IOException
Write bytes to output or random access file.

Parameters:
data - the byte array to write
offset - the start position to write from
length - the number of bytes to write
Throws:
IOException - on error

createArchiveEntry

public ArchiveEntry createArchiveEntry(File inputFile,
                                       String entryName)
                                throws IOException
Creates a new zip entry taking some information from the given file and using the provided name.

The name will be adjusted to end with a forward slash "/" if the file is a directory. If the file is not a directory a potential trailing forward slash will be stripped from the entry name.

Must not be used if the stream has already been closed.

Specified by:
createArchiveEntry in class ArchiveOutputStream
Returns:
the ArchiveEntry set up with details from the file
Throws:
IOException
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