需要把Jar包丢进配置文件夹的lib目录下才行
onEnable()时调用addBukkitLibraries()即可！

public void addBukkitLibraries()
{
        try
            {
                Method method = URLClassLoader.class.getDeclaredMethod("addURL",new Class[] { URL.class });
                method.setAccessible(true);
                ClassLoader loader = this.getClassLoader();
                for (File file : new File(this.getDataFolder(), "lib").listFiles())
                {
                    if (file.getName().endsWith(".jar"))
                    {
                        URL url = file.toURI().toURL();
                        method.invoke(loader, new Object[] { url });
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }