java 加载classpath之外的类

String rulesClassPath = "d:\\rules";
File file = new File(rulesClassPath);
URL url = file.toURL();
URLClassLoader urlLoader = new URLClassLoader(new URL[]{url},this.getClass().getClassLoader());
String className="org.sunnidy.AppBaseVO";//注意该className是rulesClassPath 下的类全名
Class c = urlLoader.loadClass(className);