Java : ZipEntry - API Examples

ZipEntry (Java SE 19 & JDK 19) API Examples.
You will find code examples on most ZipEntry methods.


Summary

This class is used to represent a ZIP file entry.

Class diagram

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

// --------
// Compression
try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    zos.putNextEntry(new ZipEntry("bbb.txt"));
    zos.write("YYYYY".getBytes());

    zos.putNextEntry(new ZipEntry("ccc.txt"));
    zos.write("ZZZZZ".getBytes());
}

// --- PowerShell ---
//PS R:\java-work> ls -name
//aaa.zip
//
//PS R:\java-work> Expand-Archive .\aaa.zip .
//PS R:\java-work> ls -name
//aaa.zip
//bbb.txt
//ccc.txt
//
//PS R:\java-work> cat .\bbb.txt
//YYYYY
//PS R:\java-work> cat .\ccc.txt
//ZZZZZ

// --------
// Decompression
try (final var zis = new ZipInputStream(Files.newInputStream(path))) {
    final var entry1 = zis.getNextEntry();
    if (entry1 != null) {
        System.out.println(entry1.getName()); // bbb.txt

        final var uncompressed = zis.readAllBytes();
        System.out.println(Arrays.toString(uncompressed)); // [89, 89, 89, 89, 89]
        System.out.println(new String(uncompressed)); // YYYYY
    }

    final var entry2 = zis.getNextEntry();
    if (entry2 != null) {
        System.out.println(entry2.getName()); // ccc.txt

        final var uncompressed = zis.readAllBytes();
        System.out.println(Arrays.toString(uncompressed)); // [90, 90, 90, 90, 90]
        System.out.println(new String(uncompressed)); // ZZZZZ
    }

    System.out.println(zis.getNextEntry()); // null
}

Fields

static final int CENATT

Central directory (CEN) header internal file attributes field offset.

System.out.println(ZipEntry.CENATT); // 36

static final int CENATX

Central directory (CEN) header external file attributes field offset.

System.out.println(ZipEntry.CENATX); // 38

static final int CENCOM

Central directory (CEN) header comment length field offset.

System.out.println(ZipEntry.CENCOM); // 32

static final int CENCRC

Central directory (CEN) header uncompressed file crc-32 value field offset.

System.out.println(ZipEntry.CENCRC); // 16

static final int CENDSK

Central directory (CEN) header disk number start field offset.

System.out.println(ZipEntry.CENDSK); // 34

static final int CENEXT

Central directory (CEN) header extra field length field offset.

System.out.println(ZipEntry.CENEXT); // 30

static final int CENFLG

Central directory (CEN) header encrypt, decrypt flags field offset.

System.out.println(ZipEntry.CENFLG); // 8

static final int CENHDR

Central directory (CEN) header size in bytes (including signature).

System.out.println(ZipEntry.CENHDR); // 46

static final int CENHOW

Central directory (CEN) header compression method field offset.

System.out.println(ZipEntry.CENHOW); // 10

static final int CENLEN

Central directory (CEN) header uncompressed size field offset.

System.out.println(ZipEntry.CENLEN); // 24

static final int CENNAM

Central directory (CEN) header filename length field offset.

System.out.println(ZipEntry.CENNAM); // 28

static final int CENOFF

Central directory (CEN) header LOC header offset field offset.

System.out.println(ZipEntry.CENOFF); // 42

static final long CENSIG

Central directory (CEN) header signature.

System.out.printf("%#x", ZipEntry.CENSIG); // 0x2014b50

static final int CENSIZ

Central directory (CEN) header compressed size field offset.

System.out.println(ZipEntry.CENSIZ); // 20

static final int CENTIM

Central directory (CEN) header modification time field offset.

System.out.println(ZipEntry.CENTIM); // 12

static final int CENVEM

Central directory (CEN) header version made by field offset.

System.out.println(ZipEntry.CENVEM); // 4

static final int CENVER

Central directory (CEN) header version needed to extract field offset.

System.out.println(ZipEntry.CENVER); // 6

static final int DEFLATED

Compression method for compressed (deflated) entries.

System.out.println(ZipEntry.DEFLATED); // 8

static final int ENDCOM

End of central directory (END) header zip file comment length field offset.

System.out.println(ZipEntry.ENDCOM); // 20

static final int ENDHDR

End of central directory (END) header size in bytes (including signature).

System.out.println(ZipEntry.ENDHDR); // 22

static final int ENDOFF

End of central directory (END) header offset for the first CEN header field offset.

System.out.println(ZipEntry.ENDOFF); // 16

static final long ENDSIG

End of central directory (END) header signature.

System.out.printf("%#x", ZipEntry.ENDSIG); // 0x6054b50

static final int ENDSIZ

End of central directory (END) header central directory size in bytes field offset.

System.out.println(ZipEntry.ENDSIZ); // 12

static final int ENDSUB

End of central directory (END) header number of entries on this disk field offset.

System.out.println(ZipEntry.ENDSUB); // 8

static final int ENDTOT

End of central directory (END) header total number of entries field offset.

System.out.println(ZipEntry.ENDTOT); // 10

static final int EXTCRC

Extra local (EXT) header uncompressed file crc-32 value field offset.

System.out.println(ZipEntry.EXTCRC); // 4

static final int EXTHDR

Extra local (EXT) header size in bytes (including signature).

System.out.println(ZipEntry.EXTHDR); // 16

static final int EXTLEN

Extra local (EXT) header uncompressed size field offset.

System.out.println(ZipEntry.EXTLEN); // 12

static final long EXTSIG

Extra local (EXT) header signature.

System.out.printf("%#x", ZipEntry.EXTSIG); // 0x8074b50

static final int EXTSIZ

Extra local (EXT) header compressed size field offset.

System.out.println(ZipEntry.EXTSIZ); // 8

static final int LOCCRC

Local file (LOC) header uncompressed file crc-32 value field offset.

System.out.println(ZipEntry.LOCCRC); // 14

static final int LOCEXT

Local file (LOC) header extra field length field offset.

System.out.println(ZipEntry.LOCEXT); // 28

static final int LOCFLG

Local file (LOC) header general purpose bit flag field offset.

System.out.println(ZipEntry.LOCFLG); // 6

static final int LOCHDR

Local file (LOC) header size in bytes (including signature).

System.out.println(ZipEntry.LOCHDR); // 30

static final int LOCHOW

Local file (LOC) header compression method field offset.

System.out.println(ZipEntry.LOCHOW); // 8

static final int LOCLEN

Local file (LOC) header uncompressed size field offset.

System.out.println(ZipEntry.LOCLEN); // 22

static final int LOCNAM

Local file (LOC) header filename length field offset.

System.out.println(ZipEntry.LOCNAM); // 26

static final long LOCSIG

Local file (LOC) header signature.

System.out.printf("%#x", ZipEntry.LOCSIG); // 0x4034b50

static final int LOCSIZ

Local file (LOC) header compressed size field offset.

System.out.println(ZipEntry.LOCSIZ); // 18

static final int LOCTIM

Local file (LOC) header modification time field offset.

System.out.println(ZipEntry.LOCTIM); // 10

static final int LOCVER

Local file (LOC) header version needed to extract field offset.

System.out.println(ZipEntry.LOCVER); // 4

static final int STORED

Compression method for uncompressed entries.

System.out.println(ZipEntry.STORED); // 0

Constructors

ZipEntry (String name)

Creates a new zip entry with the specified name.

final var input = "aaaaa".getBytes();

// [97, 97, 97, 97, 97]
System.out.println(Arrays.toString(input));

final var out = new ByteArrayOutputStream();
try (final var zos = new ZipOutputStream(out)) {
    final var entry = new ZipEntry("aaa.txt");
    System.out.println(entry.getName()); // aaa.txt

    zos.putNextEntry(entry);
    zos.write(input);
}

final var compressed = out.toByteArray();
System.out.println(compressed.length); // 133

// [80, 75, 3, 4, 20, 0, 8, 8, 8, 0, -106, -118, 63, 86, 0, 0, 0, 0, ...]
System.out.println(Arrays.toString(compressed));

ZipEntry (ZipEntry e)

Creates a new zip entry with fields taken from the specified zip entry.

final var entry1 = new ZipEntry("aaa.txt");
entry1.setComment("comment!");

final var fileTime = FileTime.from(
        ZonedDateTime.of(2100, 1, 1, 0, 0, 0, 0, ZoneOffset.UTC).toInstant());
entry1.setCreationTime(fileTime);

System.out.println(entry1.getName()); // aaa.txt
System.out.println(entry1.getComment()); // comment!
System.out.println(entry1.getCreationTime()); // 2100-01-01T00:00:00Z

final var entry2 = new ZipEntry(entry1);
System.out.println(entry2.getName()); // aaa.txt
System.out.println(entry2.getComment()); // comment!
System.out.println(entry2.getCreationTime()); // 2100-01-01T00:00:00Z

Methods

Object clone ()

Returns a copy of this entry.

final var entry = new ZipEntry("aaa.txt");
entry.setComment("comment!");

final var fileTime = FileTime.from(
        ZonedDateTime.of(2100, 1, 1, 0, 0, 0, 0, ZoneOffset.UTC).toInstant());
entry.setCreationTime(fileTime);

System.out.println(entry.getName()); // aaa.txt
System.out.println(entry.getComment()); // comment!
System.out.println(entry.getCreationTime()); // 2100-01-01T00:00:00Z

if (entry.clone() instanceof ZipEntry cloned) {
    System.out.println(cloned.getName()); // aaa.txt
    System.out.println(cloned.getComment()); // comment!
    System.out.println(cloned.getCreationTime()); // 2100-01-01T00:00:00Z
}

String getComment ()

Returns the comment string for the entry.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final var entry1 = new ZipEntry("bbb.txt");
    entry1.setComment("BBB!");
    zos.putNextEntry(entry1);

    final var entry2 = new ZipEntry("ccc.txt");
    entry2.setComment("CCC!");
    zos.putNextEntry(entry2);
}

System.out.println(Files.size(path)); // 246

try (final var zipFile = new ZipFile(path.toFile())) {
    zipFile.stream().forEach(entry -> {
        System.out.println("-- entry --");
        System.out.println("name : " + entry.getName());
        System.out.println("comment : " + entry.getComment());
    });

    // Result
    // ↓
    //-- entry --
    //name : bbb.txt
    //comment : BBB!
    //-- entry --
    //name : ccc.txt
    //comment : CCC!
}

long getCompressedSize ()

Returns the size of the compressed entry data.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final var input = "aaaaaaaaaa".getBytes();
    System.out.println(input.length); // 10

    final var entry = new ZipEntry("aaa.txt");
    System.out.println(entry.getSize()); // -1
    System.out.println(entry.getCompressedSize()); // -1
    System.out.println(entry.getCrc()); // -1

    zos.putNextEntry(entry);
    zos.write(input);
    zos.closeEntry();

    System.out.println(entry.getSize()); // 10
    System.out.println(entry.getCompressedSize()); // 5
    System.out.println(entry.getCrc()); // 1276235248
}

long getCrc ()

Returns the CRC-32 checksum of the uncompressed entry data.

Please see getCompressedSize().

FileTime getCreationTime ()

Returns the creation time of the entry.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final var fileTime = FileTime.from(
            ZonedDateTime.of(2100, 1, 1, 0, 0, 0, 0, ZoneOffset.UTC).toInstant());
    System.out.println(fileTime); // 2100-01-01T00:00:00Z

    final var entry = new ZipEntry("bbb.txt");
    entry.setCreationTime(fileTime);
    zos.putNextEntry(entry);
}

System.out.println(Files.size(path)); // 202

try (final var zipFile = new ZipFile(path.toFile())) {
    zipFile.stream().forEach(entry -> {
        System.out.println("-- entry --");
        System.out.println("name : " + entry.getName());
        System.out.println("creation time : " + entry.getCreationTime());
    });

    // Result
    // ↓
    //-- entry --
    //name : bbb.txt
    //creation time : 2100-01-01T00:00:00Z
}

byte[] getExtra ()

Returns the extra field data for the entry.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final byte[] extra = {1, 2, 3, 4, 5};
    final var entry = new ZipEntry("bbb.txt");
    entry.setExtra(extra);
    zos.putNextEntry(entry);
}

System.out.println(Files.size(path)); // 140

try (final var zipFile = new ZipFile(path.toFile())) {
    zipFile.stream().forEach(entry -> {
        System.out.println("-- entry --");
        System.out.println("name : " + entry.getName());
        System.out.println("extra : " + Arrays.toString(entry.getExtra()));
    });

    // Result
    // ↓
    //-- entry --
    //name : bbb.txt
    //extra : [1, 2, 3, 4, 5]
}

FileTime getLastAccessTime ()

Returns the last access time of the entry.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final var fileTime = FileTime.from(
            ZonedDateTime.of(2100, 1, 1, 0, 0, 0, 0, ZoneOffset.UTC).toInstant());
    System.out.println(fileTime); // 2100-01-01T00:00:00Z

    final var entry = new ZipEntry("bbb.txt");
    entry.setLastAccessTime(fileTime);
    zos.putNextEntry(entry);
}

System.out.println(Files.size(path)); // 202

try (final var zipFile = new ZipFile(path.toFile())) {
    zipFile.stream().forEach(entry -> {
        System.out.println("-- entry --");
        System.out.println("name : " + entry.getName());
        System.out.println("last access time : " + entry.getLastAccessTime());
    });

    // Result
    // ↓
    //-- entry --
    //name : bbb.txt
    //last access time : 2100-01-01T00:00:00Z
}

FileTime getLastModifiedTime ()

Returns the last modification time of the entry.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

System.out.println(Instant.now()); // 2023-02-15T09:42:49.865711800Z

try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final var entry1 = new ZipEntry("bbb.txt");
    zos.putNextEntry(entry1);

    final var fileTime = FileTime.from(
            ZonedDateTime.of(2100, 1, 1, 0, 0, 0, 0, ZoneOffset.UTC).toInstant());
    System.out.println(fileTime); // 2100-01-01T00:00:00Z

    final var entry2 = new ZipEntry("ccc.txt");
    entry2.setLastModifiedTime(fileTime);
    zos.putNextEntry(entry2);
}

System.out.println(Files.size(path)); // 310

try (final var zipFile = new ZipFile(path.toFile())) {
    zipFile.stream().forEach(entry -> {
        System.out.println("-- entry --");
        System.out.println("name : " + entry.getName());
        System.out.println("last modified time : " + entry.getLastModifiedTime());
    });

    // Result
    // ↓
    //-- entry --
    //name : bbb.txt
    //last modified time : 2023-02-15T09:42:48Z
    //-- entry --
    //name : ccc.txt
    //last modified time : 2100-01-01T00:00:00Z
}

int getMethod ()

Returns the compression method of the entry.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final var input = "aaaaaaaaaa".getBytes();
    System.out.println(input.length); // 10

    final var crc = new CRC32();
    crc.update(input);
    System.out.println(crc.getValue()); // 1276235248

    final var entry1 = new ZipEntry("bbb.txt");
    entry1.setMethod(ZipEntry.STORED);
    entry1.setCrc(crc.getValue());
    entry1.setSize(input.length);

    zos.putNextEntry(entry1);
    zos.write(input);

    final var entry2 = new ZipEntry("ccc.txt");
    entry2.setMethod(ZipEntry.STORED);
    entry2.setCrc(crc.getValue());
    entry2.setCompressedSize(input.length);

    zos.putNextEntry(entry2);
    zos.write(input);
}

System.out.println(Files.size(path)); // 222

try (final var zipFile = new ZipFile(path.toFile())) {
    zipFile.stream().forEach(entry -> {
        System.out.println("-- entry --");
        System.out.println("name : " + entry.getName());
        System.out.println("sorted : " + (entry.getMethod() == ZipEntry.STORED));
        System.out.println("crc : " + entry.getCrc());
        System.out.println("size : " + entry.getSize());
        System.out.println("compressed size : " + entry.getCompressedSize());
    });

    // Result
    // ↓
    //-- entry --
    //name : bbb.txt
    //sorted : true
    //crc : 1276235248
    //size : 10
    //compressed size : 10
    //-- entry --
    //name : ccc.txt
    //sorted : true
    //crc : 1276235248
    //size : 10
    //compressed size : 10
}

String getName ()

Returns the name of the entry.

Please see ZipEntry(String name).

long getSize ()

Returns the uncompressed size of the entry data.

Please see getCompressedSize().

long getTime ()

Returns the last modification time of the entry.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

System.out.println(Instant.now()); // 2023-02-15T10:04:06.918957400Z

try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final var entry1 = new ZipEntry("bbb.txt");
    zos.putNextEntry(entry1);

    final var instant = ZonedDateTime.of(2100, 1, 1, 0, 0, 0, 0, ZoneOffset.UTC).toInstant();
    System.out.println(instant); // 2100-01-01T00:00:00Z

    final var entry2 = new ZipEntry("ccc.txt");
    entry2.setTime(instant.toEpochMilli());
    zos.putNextEntry(entry2);
}

try (final var zipFile = new ZipFile(path.toFile())) {
    zipFile.stream().forEach(entry -> {
        System.out.println("-- entry --");
        System.out.println("name : " + entry.getName());
        System.out.println("time : " + Instant.ofEpochMilli(entry.getTime()));
    });

    // Result
    // ↓
    //-- entry --
    //name : bbb.txt
    //time : 2023-02-15T10:04:06Z
    //-- entry --
    //name : ccc.txt
    //time : 2100-01-01T00:00:00Z
}

LocalDateTime getTimeLocal ()

Returns the last modification time of the entry in local date-time.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

System.out.println(LocalDateTime.now()); // 2023-02-15T19:14:25.556582500

try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final var entry1 = new ZipEntry("bbb.txt");
    zos.putNextEntry(entry1);

    final var time = LocalDateTime.of(2100, 1, 1, 0, 0);
    System.out.println(time); // 2100-01-01T00:00

    final var entry2 = new ZipEntry("ccc.txt");
    entry2.setTimeLocal(time);
    zos.putNextEntry(entry2);
}

System.out.println(Files.size(path)); // 238

try (final var zipFile = new ZipFile(path.toFile())) {
    zipFile.stream().forEach(entry -> {
        System.out.println("-- entry --");
        System.out.println("name : " + entry.getName());
        System.out.println("time : " + entry.getTimeLocal());
    });

    // Result
    // ↓
    //-- entry --
    //name : bbb.txt
    //time : 2023-02-15T19:14:24
    //-- entry --
    //name : ccc.txt
    //time : 2100-01-01T00:00
}

int hashCode ()

Returns the hash code value for this entry.

final var entry1 = new ZipEntry("aaa.txt");
System.out.println(entry1.hashCode()); // -1238361277

final var entry2 = new ZipEntry("bbb.txt");
System.out.println(entry2.hashCode()); // -321304924

boolean isDirectory ()

Returns true if this is a directory entry.

final var path = Path.of("R:", "java-work", "aaa.zip");
System.out.println(path); // R:\java-work\aaa.zip

// --------
// Compression
try (final var zos = new ZipOutputStream(Files.newOutputStream(path))) {
    final var entry = new ZipEntry("dir/");
    zos.putNextEntry(entry);
    System.out.println(entry.isDirectory()); // true

    zos.putNextEntry(new ZipEntry("dir/bbb.txt"));
    zos.write("ZZZZZ".getBytes());
}

// --- PowerShell ---
//PS R:\java-work> ls -name
//aaa.zip
//
//PS R:\java-work> Expand-Archive .\aaa.zip .
//PS R:\java-work> ls -name
//dir
//aaa.zip
//
//PS R:\java-work> cat .\dir\bbb.txt
//ZZZZZ

// --------
// Decompression
try (final var zis = new ZipInputStream(Files.newInputStream(path))) {
    final var entry1 = zis.getNextEntry();
    if (entry1 != null) {
        System.out.println(entry1.getName()); // dir/
        System.out.println(entry1.isDirectory()); // true
    }

    final var entry2 = zis.getNextEntry();
    if (entry2 != null) {
        System.out.println(entry2.getName()); // dir/bbb.txt
        System.out.println(entry2.isDirectory()); // false

        final var uncompressed = zis.readAllBytes();
        System.out.println(Arrays.toString(uncompressed)); // [90, 90, 90, 90, 90]
        System.out.println(new String(uncompressed)); // ZZZZZ
    }

    System.out.println(zis.getNextEntry()); // null
}

void setComment (String comment)

Sets the optional comment string for the entry.

Please see getComment().

void setCompressedSize (long csize)

Sets the size of the compressed entry data.

Please see getMethod().

void setCrc (long crc)

Sets the CRC-32 checksum of the uncompressed entry data.

Please see getMethod().

ZipEntry setCreationTime (FileTime time)

Sets the creation time of the entry.

Please see getCreationTime().

void setExtra (byte[] extra)

Sets the optional extra field data for the entry.

Please see getExtra().

ZipEntry setLastAccessTime (FileTime time)

Sets the last access time of the entry.

Please see getLastAccessTime().

ZipEntry setLastModifiedTime (FileTime time)

Sets the last modification time of the entry.

Please see getLastModifiedTime().

void setMethod (int method)

Sets the compression method for the entry.

Please see getMethod().

void setSize (long size)

Sets the uncompressed size of the entry data.

Please see getMethod().

void setTime (long time)

Sets the last modification time of the entry.

Please see getTime().

void setTimeLocal (LocalDateTime time)

Sets the last modification time of the entry in local date-time.

Please see getTimeLocal().

String toString ()

Returns a string representation of the ZIP entry.

final var entry1 = new ZipEntry("aaa.txt");
final var str1 = entry1.toString();
System.out.println(str1); // aaa.txt

final var entry2 = new ZipEntry("bbb.txt");
final var str2 = entry2.toString();
System.out.println(str2); // bbb.txt

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