LibPathHacker.java

package me.chenyi.mm.util;

import java.io.File;
import java.io.IOException;
import java.lang.reflect.Field;

public class LibPathHacker {
    
    public static void addDir(String s) throws IOException {
	
	try {
	    Field field = ClassLoader.class.getDeclaredField("usr_paths");
	    field.setAccessible(true);
	    String[] paths = (String[])field.get(null);
	    
	    for (int i = 0; i < paths.length; i++) {
		if (s.equals(paths[i])) {
		    return;
		}
	    }
	    
	    String[] tmp = new String[paths.length+1];
	    System.arraycopy(paths,0,tmp,0,paths.length);
	    tmp[paths.length] = s;
	    field.set(null, tmp);
	    
	    System.setProperty("java.library.path", System.getProperty("java.library.path") + File.pathSeparator + s);
	    
	} catch (IllegalAccessException e) {
	    throw new IOException("Failed to get permissions to set library path");
	
	} catch (NoSuchFieldException e) {
	    throw new IOException("Failed to get field handle to set library path");
	}
    }
}