Ant script to Find a jar file given the class name?

how to f开发者_JS百科ind the name of jar which contains the specific class through ant script?

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We are using the following Ant code to find the jar containing our main class. It requires Ant 1.8+.

<whichresource class="${main.class}" property="main.class.url">
    <classpath>
        <fileset dir="${jar.dir}" includes="*.jar" />
    </classpath>
</whichresource>

<pathconvert property="jar.file">
    <url url="${main.class.url}" />
    <regexpmapper from="jar:file:/(.*)!.*" to="\1" />
</pathconvert>

<echo>Jar file containing main class: ${jar.file}</echo>

I hope this answers your question.

Maarten

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Try jarscan . It is a commandline java tool, it should be easy if you want to integrate it through ant also.

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I think this problem can be better solved by a 1-line (ok, 5-line) C-shell script. Suppose you are trying to find a list of jar files in some directory that contain a certain file. Try this at your csh prompt:

% cd directory_where_your_jar_files_reside
% set f2Search = filename_you_are_looking_for
% foreach jarFile (*.jar)    
? (jar tvf $jarFile | grep $f2Search > /dev/null) || echo $jarFile
? end

You can obviously concat the output to some other file if required. This is a Unix solution, dunno how to do this on Windows, sorry. Apologies for not answering the Ant question, but others have answered it already. Hope this helps, - M.S.

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That's not really what Ant is for.

Ant is primarily a build tool, and it's core functionalities revolve around that. Yes, it can be used for additional functions, but it's still best to use it what it was intended for. Finding a class inside a JAR file isn't what it's good at.

You may be better off just doing this in Java. Java offers functionality to open up JAR files and inspect the contents. You can use those to find the class you are looking for. Or, use another tool that's intended to do that, such as the Jarscan that Biju mentions.

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I agree with rfeak this is not what ANT is designed for. Having said that, it can very be a frustrating to determine how to resolve missing class dependencies.....

I use the findjar website. It indexes most of the available open source libraries.

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If you really need to do this, one approach that might work is to loop through all the JAR files and pass each one to the available task as the lone classpath path element. The class you're interested in would be used for the classname attribute.

Edit: Since it sounds like you're now entertaining non-Ant solutions, here's a variation of the find-my-class code:

import java.net.URL;

public class ClassFinder {

    public static void main(String[] args) throws ClassNotFoundException {
        Class<?> c = Class.forName(args[0]);
        URL url = c.getResource(c.getSimpleName() + ".class");
        System.out.println("location of " + args[0] + ": " + url);
    }
}

With Java 6, you can use classpath wildcards (see "Understanding class path wildcards"), so it should be easy to include your directory of JARs and see how fast it is.

Edit2: And if you want to find multiple locations...

import java.io.IOException;
import java.net.JarURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Enumeration;

public class ClassFinder {

    public static void main(String[] args) throws IOException {
        String classResourceName = args[0].replaceAll("\\.", "/") + ".class";
        ClassLoader loader = ClassFinder.class.getClassLoader();
        Enumeration<URL> classResources = (loader == null) ? ClassLoader.getSystemResources(classResourceName) : loader.getResources(classResourceName);
        if (classResources.hasMoreElements()) {
            System.out.println("Locations of " + args[0] + ":");
            while (classResources.hasMoreElements()) {
                URL url = classResources.nextElement();
                URLConnection conn = url.openConnection();
                String loc = (conn instanceof JarURLConnection) ? ((JarURLConnection)conn).getJarFile().getName() : url.toString();
                System.out.println(loc);
            }
        } else {
            System.out.println("No locations found for " + args[0]);
        }
    }
}