java：查看jar中的内容

jar其实就是zip格式，可以用常见的解压缩软件打开。也可以使用jar命令：

$ jar tvf HelloJava.jar 
     0 Wed Jan 28 21:01:16 CST 2015 META-INF/
   210 Wed Jan 28 21:01:14 CST 2015 META-INF/MANIFEST.MF
     0 Wed Jan 28 21:01:16 CST 2015 me/
     0 Wed Jan 28 21:01:16 CST 2015 me/letian/
  2030 Wed Jan 28 21:01:16 CST 2015 me/letian/HelloJava.class
    21 Wed Jan 28 21:01:16 CST 2015 me/letian/user.properties

jar用法：

$ jar
Usage: jar {ctxui}[vfm0Me] [jar-file] [manifest-file] [entry-point] [-C dir] files ...
Options:
    -c  create new archive
    -t  list table of contents for archive
    -x  extract named (or all) files from archive
    -u  update existing archive
    -v  generate verbose output on standard output
    -f  specify archive file name
    -m  include manifest information from specified manifest file
    -e  specify application entry point for stand-alone application 
        bundled into an executable jar file
    -0  store only; use no ZIP compression
    -M  do not create a manifest file for the entries
    -i  generate index information for the specified jar files
    -C  change to the specified directory and include the following file
If any file is a directory then it is processed recursively.
The manifest file name, the archive file name and the entry point name are
specified in the same order as the 'm', 'f' and 'e' flags.

Example 1: to archive two class files into an archive called classes.jar: 
       jar cvf classes.jar Foo.class Bar.class 
Example 2: use an existing manifest file 'mymanifest' and archive all the
           files in the foo/ directory into 'classes.jar': 
       jar cvfm classes.jar mymanifest -C foo/ .