How can I call Perl from Java?

Question

I have a Perl module that I would like to use from Java. Is there a way to call this code using either ActiveState Perl on Windows or the generic Perl that comes with Linux? I have found references to JPL but it doesn't appear to be maintained anymore.

Answer 1

Inline-Java is the usual library to call java from Perl, and this post propose a org.perl.java module which should allow calling Perl from Java, as asked.

However, because of the unpredictability of the JNI implementations for different JVMs it is difficult to say what combinations of JVM and Perl will work. Typically, what is required is Perl with MULTIPLICITY, and threads compiled in. That means he uses a custom built Perl.

Otherwise, Inline::Java::Callback allows you to call Perl functions from Java. To do this you need to create an org.perl.inline.java.InlinePerlCaller object. Here is a example of a typical use:

use Inline Java => <<END ;
import java.util.* ;
import org.perl.inline.java.* ;

class Pod_regexp extends InlineJavaPerlCaller {
    public Pod_regexp() throws InlineJavaException {
    }

    public boolean match(String target, String pattern)
        throws InlineJavaException {
        try {
            String m = (String)CallPerlSub("main::regexp",
            new Object [] {target, pattern}) ;

            if (m.equals("1")){
            return true ;
        }
    }
    catch (InlineJavaPerlException pe){
        // $@ is in pe.GetObject()
    }

    return false ;
    }
}
END

my $re = new Pod_regexp() ;
my $match = $re->match("Inline::Java", "^Inline") ;
print($match . "n") ; # prints 1

sub regexp {
    my $target = shift ;
    my $pattern = shift ;

    return ($target =~ /$pattern/) ;
} 

Answer 2

Is this not what Runtime.exec() is for?

Runtime.getRuntime().exec("/usr/bin/perl myPerl.pl");

Or am I misunderstanding the question?

Answer 3

Rakudo allows you to run Perl6 inside a JVM, and there is a Perl5 add-on that allows you to run most old code, although no XS of course. There is also JERL that runs current microperl inside the JVM. It depends a lot on what you're looking to do, but those are worth checking out.

Answer 4

我使用过一点 Inline::Java，发现它有点繁琐，如果我有时间，我可能会使用 Web 服务重新实现并以这种方式调用 perl 代码。

Answer 5

Sleep is a scripting language with an interpreter that runs in the JVM. From what I understand the Sleep language is basically Perl with some extensions. Your code may be able to run in Sleep. If it does you can instantiate the interpreter, run the code and retrieve the result.

Answer 6

我在 JavaWorld 上找到了 Robert Lawson 的实现，它使用 XML-RPC 从您的 Java 代码中调用 Perl 例程：Call Perlroutines from Java

Answer 7

I know this is old, but I recently came across the same needs. I found JPerl more convenient then Inline::Java::PerlInterpreter .

Answer 8

Guess it really depends on what your perl code is, and what you're trying to do..

If just using exec() is too simple, something like gearman could be helpful

Answer 9

I don't know how stable will that be ,or how well maintained it is, so, another option would be to write a script that does something your application will need and then execute that script from Java. Not the most elegant way, but it works.