java从磁盘加载class反射调用方法

try {
    File file = new File("C:\\Users\\classes\\com\\test");
    URL[] urls = {file.toURI().toURL()};
    URLClassLoader urlClassLoader = new URLClassLoader(urls);
    Class clazz = urlClassLoader.loadClass("Foo");
    java.lang.Object fooObject = clazz.newInstance();
    java.lang.reflect.Field[] fields = clazz.getDeclaredFields();
    for (int i = 0; i < fields.length; i ++) {
        java.lang.reflect.Field field = fields[i];
        String name = field.getName();
        System.out.println("field->" + name);
    }
    Method computeFreightFeeMethod = null;
    java.lang.reflect.Method[] methods = clazz.getMethods();
    for (int i = 0; i < methods.length; i ++) {
        Method method = methods[i];
        String name = method.getName();
        System.out.println("method->" + name);
        if (name.equals("computeFreightFee")) {
            computeFreightFeeMethod = method;
        }
    }
    if (computeFreightFeeMethod != null) {
        Class[] parameterTypes = computeFreightFeeMethod.getParameterTypes();
        int parameterCount = computeFreightFeeMethod.getParameterCount();
        System.out.println("打印参数数量->" + parameterCount);
        for (int i = 0; i < parameterTypes.length; i ++) {
            System.out.println("打印参数类型->" + parameterTypes[i].toString());
        }
        Object result = computeFreightFeeMethod.invoke(fooObject, 1);
        Integer fee = (Integer) result;
        System.out.println("fee->" + fee);
    }
} catch (MalformedURLException e) {
    e.printStackTrace();
} catch (ClassNotFoundException e) {
    e.printStackTrace();
} catch (IllegalAccessException illegalAccessException) {
    illegalAccessException.printStackTrace();
} catch (InstantiationException instantiationException) {
    instantiationException.printStackTrace();
} catch (InvocationTargetException invocationTargetException) {
    invocationTargetException.printStackTrace();
}