add All Jars To Class Path - Java Reflection

Java examples for Reflection:Class Path

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Description

add All Jars To Class Path

Demo Code

/*******************************************************************************
 * CopyRight (c) 2005-2011 GLOBE Co, Ltd. All rights reserved.
 * Filename:    JVMUtil.java/*from   w ww . j a  va  2  s. co m*/
 * Creator:     joe
 * Create-Date: 2011-4-27 ????10:39:08
 *******************************************************************************/
//package com.java2s;
import java.io.File;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Main {
    public static String[] addAllJarsToClassPath(String dirName) {
        List<String> ret = new ArrayList<String>();

        File dir = new File(dirName);
        if (dir.isDirectory()) {
            File[] files = dir.listFiles();
            for (File file : files) {
                if (file.isDirectory()) {
                    ret.addAll(Arrays.asList(addAllJarsToClassPath(file
                            .getAbsolutePath())));
                } else {
                    String filename = file.getName().toLowerCase();
                    if (filename.endsWith(".jar")) {
                        if (appendtoClassPath(file.getAbsolutePath())) {
                            ret.add(file.getAbsolutePath());
                        }
                    }
                }
            }
        }

        return ret.toArray(new String[0]);
    }

    public static boolean appendtoClassPath(String name) {
        // ??? JDK 1.6
        // from JDK DOC "java.lang.instrument Interface Instrumentation"
        // ...
        // The system class loader supports adding a JAR file to be searched
        // if it implements a method named appendToClassPathForInstrumentation
        // which takes a single parameter of type java.lang.String.
        // The method is not required to have public access. The name of the JAR
        // file
        // is obtained by invoking the getName() method on the jarfile and this
        // is
        // provided as the parameter to the appendtoClassPathForInstrumentation
        // method.
        // ...

        try {
            ClassLoader clsLoader = ClassLoader.getSystemClassLoader();
            Method appendToClassPathMethod = clsLoader.getClass()
                    .getDeclaredMethod(
                            "appendToClassPathForInstrumentation",
                            String.class);
            if (null != appendToClassPathMethod) {
                appendToClassPathMethod.setAccessible(true);
                appendToClassPathMethod.invoke(clsLoader, name);
            }
            return true;
        } catch (SecurityException e) {
            e.printStackTrace();
        } catch (NoSuchMethodException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InvocationTargetException e) {
            e.printStackTrace();
        }
        return false;
    }
}

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