BAT file to create Java CLASSPATH

Question

I want to distribute a command-line application written in Java on Windows.

My application is distributed as a zip file, which has a lib directory entry which has the .jar files needed for invoking my main class. Currently, for Unix environments, I have a shell script which invokes the java command with a CLASSPATH created by appending all files in lib directory.

How do I write a .BAT file with similar functionality? What is the equivalent of find Unix command in Windows world?

Answer 1

Why would you use find? Presumably you know all the libraries your jar file needs ahead of time, so why not just list them?

Alternatively, you could always use -Djava.ext.dirs=lib and let it pick up everything that way.

Answer 2

SET CLASSPATH=""
FOR /R /lib %%a in (*.jar) DO CALL :AddToPath %%a
echo %CLASSPATH%

java -cp %CLASSPATH% com.a.b.MyClass

pause

:AddToPath
SET CLASSPATH=%1;%CLASSPATH%
GOTO :EOF

Answer 3

Since 6.0, Java supports wildcard classpaths.

Java command-line classpath syntax

Answer 4

A variation if you want the CLASSPATH setting to hold outside of the script and you didn't start the shell with /V, you can do something like this:

@echo off
FOR /R ./lib %%a in (*.jar) DO CALL :AddToPath %%a
ECHO %CLASSPATH%
GOTO :EOF

:AddToPath
SET CLASSPATH=%1;%CLASSPATH%
GOTO :EOF

Useful for setting up your environment when you are just playing around on the command line.