jarファイルからクラスをロードする その２

カレントスレッドのクラスローダに定義するように修正。すこしはマシかな…

package jarjar;
import java.io.*;

import java.lang.reflect.*;

import java.util.*;

import java.util.jar.*;
public class JarJar {
    public static void main(String args) {

        try {

            ClassLoader cloader = Thread.currentThread().getContextClassLoader();

            JarJar jarjar = new JarJar("ooweb-0.5.jar", cloader);

            jarjar.load();

            println(Class.forName("net.sf.ooweb.util.StringUtils"));

        } catch (Throwable e) {

            e.printStackTrace();

        }

    }
    private static void println(Object x) {

        System.out.println(x);

    }
    /////////////////////////////////////////////////////////////////

    private JarFile jar = null;
    private ClassLoader cloader = null;
    private Method define = null;
    private static final Integer ZERO = new Integer(0);
    public JarJar(String filename, ClassLoader cloader) throws IOException {

        this.jar = new JarFile(filename);

        this.cloader = cloader;

        Class args = { String.class, byte.class, int.class, int.class };
        try {

            define = ClassLoader.class.getDeclaredMethod("defineClass", args);

        } catch (NoSuchMethodException e) {

            throw new RuntimeException(e);

        }
        define.setAccessible(true);

    }
    public void load() throws IOException {

        Map ctx = new HashMap();
        for (Enumeration enum = jar.entries(); enum.hasMoreElements();) {

            JarEntry entry = (JarEntry) enum.nextElement();

            String name = entry.getName();
            if (entry.isDirectory() || !name.endsWith(".class"))

                continue;
            byte bs = getBytes(jar, entry);

            ctx.put(getClassName(name), bs);

        }
        Set classes = new HashSet();
        for (Iterator names = ctx.keySet().iterator(); names.hasNext();) {

            String name = (String) names.next();

            loadClasses(name, ctx, classes);

        }

    }
    private void loadClasses(String name, Map ctx, Set classes) {

        if (classes.contains(name))

            return;
        byte bs = (byte) ctx.get(name);
        try {

            defineClass(name, bs);

        } catch (NoClassDefFoundError e) {

            loadClasses(getClassName(e.getMessage()), ctx, classes);

            defineClass(name, bs);

        }
        classes.add(name);

    }
    private byte getBytes(JarFile jar, JarEntry entry) throws IOException {

        InputStream in = jar.getInputStream(entry);

        ByteArrayOutputStream out = new ByteArrayOutputStream();

        byte buf = new byte[1024];
        while (in.available() > 0) {

            int len = in.read(buf);

            out.write(buf, 0, len);

        }
        out.flush();

        in.close();

        return out.toByteArray();

    }
    private String getClassName(String name) {

        name = name.replace('/', '.');
        if (name.endsWith(".class"))

            name = name.substring(0, name.length() - 6);
        return name;

    }
    private void defineClass(String name, byte bs) {

        try {

            if (define == null) {

            }
            Object objs = { name, bs, ZERO, new Integer(bs.length) };

            define.invoke(cloader, objs);

        } catch (IllegalAccessException e) {

            throw new RuntimeException(e);

        } catch (InvocationTargetException e) {

            Throwable cause = e.getCause();
            if (cause instanceof NoClassDefFoundError)

                throw (NoClassDefFoundError) cause;
            throw new RuntimeException(e);

        }

    }
}