Comment lire un fichier .jar ou ouvrir un fichier au format jar ?
La description du format peut vous y aider ou vous donner des indications :
Il s'agit d'une modification du format ZIP pour stocker spécifiquement les applications java.
Spécifications techniques :
JAR TECHNICAL INFORMATION October 1996
JAR archive identification scheme:
A file is considered a JAR archive if it contains a predefined 64-byte
structure.
Structure description:
at byte offset 0 for 4 bytes:
Whole structure CRC32 XOR-ed with 0xffffffff and shifted
cyclically 11 bits to the right (to the lowest bit). When
counting CRC32 this field itself is assumed to be 0.
at byte offset 14 for 6 bytes:
signature: 0x1A 'J' 'a' 'r' 0x1B 0x00
other structure fields not defined.
This structure does NOT necessarily start at the head of the file.
For normal archives this structure resides at the head of the file.
However to support future JAR SFX-es you must search the first 128
kilobytes of the file for this structure (optional check for executable
'MZ' may also be done).
The remaining part of this document contains a description of the JAR
archive header information that is dumped to a text file using the "lt"
command.
The dump file should be treated as a text file. Each line has the same
syntax:
<Keyword>=<value>
These lines are assembled into a tree. Subnodes are shifted with respect
to the parent node by using two ' ' (space) characters. Example:
Chapter=1
Created=1996-09-01 17:55:05.9800000
Modified=1996-09-01 17:55:05.9800000
Comment="Some\r\ncomment"
Flags=0
File=FIRST.BAT
Created=1996-09-01 17:20:41.4400000
Modified=1996-09-01 16:37:00.0000000
LastAccess=1996-09-01 00:00:00.0000000
Size=2160
ChaptersRange=1-2
Attributes=1
File=SECOND.BAT
Created=1996-09-01 17:20:41.4400000
Modified=1996-09-01 16:37:00.0000000
LastAccess=1996-09-01 00:00:00.0000000
Size=2160
ChaptersRange=1-2
Attributes=1
Currently, the tree depth is two (only nodes and one-level subnodes) but
in future JAR versions, the depth may be increased.
You should not rely on the order in which keywords are listed. For
compatibility with future versions all unknown keywords must be
skipped. Binary keyword values (such as ANSI comments) are quoted and
encoded using escape character '\'.
This is a brief description of the currently used keywords:
Archive=
Archive keyword. Subnodes describe global archive related
information.
Created=1996-09-01 17:21:31.9100000
Archive creation time YYYY-MM-DD HH:MM:SS.SSSSSSS
Modified=1996-09-01 19:17:56.5100000
Last time archive has been modified.
VersionUsed=0101
JAR version used to update archive (1.01 in this example).
VersionToUpdate=0050
JAR version required to update archive (0.50 in this example).
VersionToExtract=0050
JAR version required to extract files from archive.
VersionToList=0050
JAR version required to list files in archive.
Flags=0
Currently, JAR archive flags is the sum of the following
constants:
1 LOCKED
2 AUTO_LOCK
4 RECOVERY RECORDS
8 SECURED
16 HIDDEN
32 ENCRYPTED/PROTECTED
Comment="Some\r\ncomment"
Optional archive comment. Escape characters:
\\ Backslash
\" Double quotation mark
\b Backspace
\n Newline
\r Carriage return
\t Tab
\ddd ASCII character in octal notation. 3 digits always used.
MaxChapter=3
Maximum chapter in archive.
Chapter=1
Chapter (#1 in this example). Subnodes supply information about
chapter.
Created=1996-09-01 17:21:31.9100000
Creation time
Modified=1996-09-01 17:21:31.9100000
Modification time
Flags=0
Chapter flags is sum of following constants:
1 LOCKED
Comment="Some\r\ncomment"
Optional chapter comment. Same format as in case of archive.
File=TESTJAR.BAT
Filename. Subnodes contain information about file.
Created=1996-09-01 17:20:41.4400000
File creation time
Modified=1996-09-01 16:37:00.0000000
File modification time
LastAccess=1996-09-01 00:00:00.0000000
File last accessed time
Size=2160
File size in bytes
ChaptersRange=1-2
Chapter range to which file belongs
Attributes=1
Sum of:
1 ARCHIVE
2 HIDDEN
4 SYSTEM
8 READONLY
16 DIRECTORY
Comment="Some\r\ncomment"
Optional file comment.
Actually, the JAR header contains more information than is currently
listed using the "lt" command. In the future we will add additional
keywords.
end of document
 Astuces pour les fichiers jar
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