Java read from zip file

Java ZipInputStream

Java ZipInputStream tutorial shows how to read ZIP files in Java with ZipInputStream .

Java ZipInputStream

ZipInputStream is a Java class that implements an input stream filter for reading files in the ZIP file format. It has support for both compressed and uncompressed entries.

ZIP

ZIP is an archive file format that supports lossless data compression. A ZIP file may contain one or more files or directories that may have been compressed. Java Archive (JAR) is built on the ZIP format.

ZipInputStream constructors

ZipInputStream has the following constructors:

ZipInputStream(InputStream in) ZipInputStream(InputStream in, Charset charset)

ZipInputStream getNextEntry

The ZipInputStream’s getNextEntry reads the next ZIP file entry and positions the stream at the beginning of the entry data.

Java read ZIP example

The following example reads the contents of a ZIP file.

package com.zetcode; import java.io.BufferedInputStream; import java.io.FileInputStream; import java.io.IOException; import java.time.LocalDate; import java.util.zip.ZipEntry; import java.util.zip.ZipInputStream; public class JavaReadZip < private final static Long MILLS_IN_DAY = 86400000L; public static void main(String[] args) throws IOException < String fileName = "src/resources/myfile.zip"; try (FileInputStream fis = new FileInputStream(fileName); BufferedInputStream bis = new BufferedInputStream(fis); ZipInputStream zis = new ZipInputStream(bis)) < ZipEntry ze; while ((ze = zis.getNextEntry()) != null) < System.out.format("File: %s Size: %d last modified: %d", ze.getName(), ze.getSize(), LocalDate.ofEpochDay(ze.getTime() / MILLS_IN_DAY)); >> > >

The example reads the given ZIP file with ZipInputStream and prints its contents to the terminal. We print the file names, their size, and the last modification time.

String fileName = "src/resources/myfile.zip";

The ZIP file is located int src/resources/ directory.

try (FileInputStream fis = new FileInputStream(fileName);

We create a FileInputStream from the file. FileInputStream is used for reading streams of raw bytes.

BufferedInputStream bis = new BufferedInputStream(fis);

For better performance, we pass the FileInputStream into the BufferedInputStream .

ZipInputStream zis = new ZipInputStream(bis)) 
A ZipInputStream is created from the buffered FileInputStream . The try-with-resources closes the streams when they are not needed anymore.
while ((ze = zis.getNextEntry()) != null) 
In a while loop, we go through the entries of the ZIP file with getNextEntry method. It returns null if there are no more entries.
System.out.format("File: %s Size: %d last modified: %d", ze.getName(), ze.getSize(), LocalDate.ofEpochDay(ze.getTime() / MILLS_IN_DAY));
 
The getName returns the name of the entry, the getSize returns the uncompressed size of the entry, and the getTime returns the last modification time of the entry.
 
Java decompress ZIP example
 
In the next example, we decompress a ZIP file in Java.
 
package com.zetcode; import java.io.BufferedInputStream; import java.io.BufferedOutputStream; import java.io.FileInputStream; import java.io.FileOutputStream; import java.nio.file.Path; import java.nio.file.Paths; import java.util.zip.ZipEntry; import java.util.zip.ZipInputStream; public class JavaUnzip < public static void main(String args[]) throws Exception < byte[] buffer = new byte[2048]; Path outDir = Paths.get("src/resources/output/"); String zipFileName = "src/resources/myfile.zip"; try (FileInputStream fis = new FileInputStream(zipFileName); BufferedInputStream bis = new BufferedInputStream(fis); ZipInputStream stream = new ZipInputStream(bis)) < ZipEntry entry; while ((entry = stream.getNextEntry()) != null) < Path filePath = outDir.resolve(entry.getName()); try (FileOutputStream fos = new FileOutputStream(filePath.toFile()); BufferedOutputStream bos = new BufferedOutputStream(fos, buffer.length)) < int len; while ((len = stream.read(buffer)) >0) < bos.write(buffer, 0, len); >> > > > >
 
The example uses ZipInputStream to read the contents of the given ZIP file and FileOutputStream and BufferedOutputStream to write the contents into a directory.
 
Path outDir = Paths.get("src/resources/output/");
 
This is the directory where we extract the contents of the ZIP file.
 
while ((entry = stream.getNextEntry()) != null) 
In the first while loop, we go through the entries of the ZIP file.
while ((len = stream.read(buffer)) > 0)
In the second while loop, we read the entries and write them to the output stream.
In this article we have presented the Java ZipInputStream class. We have created two examples to read a ZIP file and to decompress a ZIP file.
Author
My name is Jan Bodnar and I am a passionate programmer with many years of programming experience. I have been writing programming articles since 2007. So far, I have written over 1400 articles and 8 e-books. I have over eight years of experience in teaching programming.
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Java read from zip file
This class implements an input stream filter for reading files in the ZIP file format. Includes support for both compressed and uncompressed entries.
Field Summary
Fields inherited from class java.util.zip.InflaterInputStream
Fields inherited from class java.io.FilterInputStream
Constructor Summary
Method Summary
Methods inherited from class java.util.zip.InflaterInputStream
Methods inherited from class java.io.FilterInputStream
Methods inherited from class java.lang.Object
Field Detail
LOCSIG
public static final long LOCSIG
 
EXTSIG
 
public static final long EXTSIG
 
CENSIG
 
public static final long CENSIG
 
ENDSIG
 
public static final long ENDSIG
 
LOCHDR
 
public static final int LOCHDR
 
EXTHDR
 
public static final int EXTHDR
 
CENHDR
 
public static final int CENHDR
 
ENDHDR
 
public static final int ENDHDR
 
LOCVER
 
public static final int LOCVER
 
LOCFLG
 
public static final int LOCFLG
 
LOCHOW
 
public static final int LOCHOW
 
LOCTIM
 
public static final int LOCTIM
 
LOCCRC
 
public static final int LOCCRC
 
LOCSIZ
 
public static final int LOCSIZ
 
LOCLEN
 
public static final int LOCLEN
 
LOCNAM
 
public static final int LOCNAM
 
LOCEXT
 
public static final int LOCEXT
 
EXTCRC
 
public static final int EXTCRC
 
EXTSIZ
 
public static final int EXTSIZ
 
EXTLEN
 
public static final int EXTLEN
 
CENVEM
 
public static final int CENVEM
 
CENVER
 
public static final int CENVER
 
CENFLG
 
public static final int CENFLG
 
CENHOW
 
public static final int CENHOW
 
CENTIM
 
public static final int CENTIM
 
CENCRC
 
public static final int CENCRC
 
CENSIZ
 
public static final int CENSIZ
 
CENLEN
 
public static final int CENLEN
 
CENNAM
 
public static final int CENNAM
 
CENEXT
 
public static final int CENEXT
 
CENCOM
 
public static final int CENCOM
 
CENDSK
 
public static final int CENDSK
 
CENATT
 
public static final int CENATT
 
CENATX
 
public static final int CENATX
 
CENOFF
 
public static final int CENOFF
 
ENDSUB
 
public static final int ENDSUB
 
ENDTOT
 
public static final int ENDTOT
 
ENDSIZ
 
public static final int ENDSIZ
 
ENDOFF
 
public static final int ENDOFF
 
ENDCOM
 
public static final int ENDCOM
 
Constructor Detail
 
ZipInputStream
 
ZipInputStream
 
Method Detail
 
getNextEntry
 
public ZipEntry getNextEntry() throws IOException
 
closeEntry
 
available
 
Returns 0 after EOF has reached for the current entry data, otherwise always return 1. Programs should not count on this method to return the actual number of bytes that could be read without blocking.
 
read
 
Reads from the current ZIP 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.
 
skip
 
close
 
createZipEntry
 
protected ZipEntry createZipEntry(String name)
 
 Submit a bug or feature 
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples. 
Copyright © 1993, 2023, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy. 
 
Источник
 
Class ZipFile
 
Unless otherwise noted, passing a null argument to a constructor or method in this class will cause a NullPointerException to be thrown.
 
Field Summary
 
Constructor Summary
 
Method Summary
 
Methods declared in class java.lang.Object
 
Field Details
 
OPEN_READ
 
OPEN_DELETE
 
Mode flag to open a zip file and mark it for deletion. The file will be deleted some time between the moment that it is opened and the moment that it is closed, but its contents will remain accessible via the ZipFile object until either the close method is invoked or the virtual machine exits.
 
LOCSIG
 
EXTSIG
 
CENSIG
 
ENDSIG
 
LOCHDR
 
EXTHDR
 
CENHDR
 
ENDHDR
 
LOCVER
 
LOCFLG
 
LOCHOW
 
LOCTIM
 
LOCCRC
 
LOCSIZ
 
LOCLEN
 
LOCNAM
 
LOCEXT
 
EXTCRC
 
EXTSIZ
 
EXTLEN
 
CENVEM
 
CENVER
 
CENFLG
 
CENHOW
 
CENTIM
 
CENCRC
 
CENSIZ
 
CENLEN
 
CENNAM
 
CENEXT
 
CENCOM
 
CENDSK
 
CENATT
 
CENATX
 
CENOFF
 
ENDSUB
 
ENDTOT
 
ENDSIZ
 
ENDOFF
 
ENDCOM
 
Constructor Details
 
ZipFile
 
Opens a zip file for reading. First, if there is a security manager, its checkRead method is called with the name argument as its argument to ensure the read is allowed. The UTF-8 charset is used to decode the entry names and comments.
 
ZipFile
 
Opens a new ZipFile to read from the specified File object in the specified mode. The mode argument must be either OPEN_READ or OPEN_READ | OPEN_DELETE . First, if there is a security manager, its checkRead method is called with the name argument as its argument to ensure the read is allowed. The UTF-8 charset is used to decode the entry names and comments
 
ZipFile
 
Opens a ZIP file for reading given the specified File object. The UTF-8 charset is used to decode the entry names and comments.
 
ZipFile
 
Opens a new ZipFile to read from the specified File object in the specified mode. The mode argument must be either OPEN_READ or OPEN_READ | OPEN_DELETE . First, if there is a security manager, its checkRead method is called with the name argument as its argument to ensure the read is allowed.
 
ZipFile
 
Opens a zip file for reading. First, if there is a security manager, its checkRead method is called with the name argument as its argument to ensure the read is allowed.
 
ZipFile
 
Method Details
 
getComment
 
getEntry
 
getInputStream
 
Returns an input stream for reading the contents of the specified zip file entry. Closing this ZIP file will, in turn, close all input streams that have been returned by invocations of this method.
 
getName
 
entries
 
stream
 
Returns an ordered Stream over the ZIP file entries. Entries appear in the Stream in the order they appear in the central directory of the ZIP file.
 
size
 
close
 
Closes the ZIP file. Closing this ZIP file will close all of the input streams previously returned by invocations of the getInputStream method.
 
Report a bug or suggest an enhancement 
For further API reference and developer documentation see the Java SE Documentation, which contains more detailed, developer-targeted descriptions with conceptual overviews, definitions of terms, workarounds, and working code examples. Other versions. 
Java is a trademark or registered trademark of Oracle and/or its affiliates in the US and other countries. 
Copyright © 1993, 2023, Oracle and/or its affiliates, 500 Oracle Parkway, Redwood Shores, CA 94065 USA.
All rights reserved. Use is subject to license terms and the documentation redistribution policy. 
 
Источник
 
Class ZipInputStream
 
This class implements an input stream filter for reading files in the ZIP file format. Includes support for both compressed and uncompressed entries.
 
Field Summary
 
Fields declared in class java.util.zip.InflaterInputStream
 
Fields declared in class java.io.FilterInputStream
 
Constructor Summary
 
Method Summary
 
Methods declared in class java.util.zip.InflaterInputStream
 
Methods declared in class java.io.FilterInputStream
 
Methods declared in class java.io.InputStream
 
Methods declared in class java.lang.Object
 
Field Details
 
LOCSIG
 
EXTSIG
 
CENSIG
 
ENDSIG
 
LOCHDR
 
EXTHDR
 
CENHDR
 
ENDHDR
 
LOCVER
 
LOCFLG
 
LOCHOW
 
LOCTIM
 
LOCCRC
 
LOCSIZ
 
LOCLEN
 
LOCNAM
 
LOCEXT
 
EXTCRC
 
EXTSIZ
 
EXTLEN
 
CENVEM
 
CENVER
 
CENFLG
 
CENHOW
 
CENTIM
 
CENCRC
 
CENSIZ
 
CENLEN
 
CENNAM
 
CENEXT
 
CENCOM
 
CENDSK
 
CENATT
 
CENATX
 
CENOFF
 
ENDSUB
 
ENDTOT
 
ENDSIZ
 
ENDOFF
 
ENDCOM
 
Constructor Details
 
ZipInputStream
 
ZipInputStream
 
Method Details
 
getNextEntry
 
closeEntry
 
available
 
Returns 0 after EOF has reached for the current entry data, otherwise always return 1. Programs should not count on this method to return the actual number of bytes that could be read without blocking.
 
read
 
Reads from the current ZIP 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.
 
skip
 
close
 
createZipEntry
 
Report a bug or suggest an enhancement 
For further API reference and developer documentation see the Java SE Documentation, which contains more detailed, developer-targeted descriptions with conceptual overviews, definitions of terms, workarounds, and working code examples. Other versions. 
Java is a trademark or registered trademark of Oracle and/or its affiliates in the US and other countries. 
Copyright © 1993, 2023, Oracle and/or its affiliates, 500 Oracle Parkway, Redwood Shores, CA 94065 USA.
All rights reserved. Use is subject to license terms and the documentation redistribution policy. 
 
Источник