java 之 反射

1、

@Test
public void invokeDemo() throws Exception {

    UserController userController = new UserController();
    //获取字节码对象
    Class<? extends UserController> clazz = userController.getClass();
    //创建service对象
    UserService userService = new UserService();
    System.out.println(userService);//输出方法值
    //通过类型获取属性
    Field declaredField = clazz.getDeclaredField("userService");
    String name = declaredField.getName();
    //拼接set方法名称
    String setMethod = "set" + name.substring(0, 1).toUpperCase() + name.substring(1, name.length());
    //获取方法
    Method method = clazz.getMethod(setMethod, UserService.class);
    //反射
    method.invoke(userController, userService);

    System.out.println(userController.getUserService());
}