class

反射

…衆ロ難τιáo~ 提交于 2020-01-24 01:24:02
反射 1.获得反射对象的几种方式 //测试Class类的创建方式有哪些 public class test02 { public static void main(String[] args) throws ClassNotFoundException { Person person = new Student(); System.out.println("这个人是" + person.name); //方式一:通过对象获得 Class c1 = person.getClass(); System.out.println(c1.hashCode()); //方式二:forname获得 Class c2 = Class.forName("com.kk.reflection.Student"); System.out.println(c2.hashCode()); //方式三:通过类名.class Class<Student> c3 = Student.class; System.out.println(c3.hashCode()); //方式四:基本内置类型的包装类都有一个TYPE属性 Class c4 = Integer.TYPE; System.out.println(c4); //获得父类类型 Class c5 = c1.getSuperclass(); System.out

Can't call a decorator within the imported sub-class of a cherrpy application (site tree)

孤人 提交于 2020-01-24 00:27:09
问题 I am using cherrypy as a web server, and I want to check a user's logged-in status before returning the page. This works on methods in the main Application class (in site.py ) but gives an error when I call the same decorated function on method in a class that is one layer deeper in the webpage tree (in a separate file). validate_user() is the function used as a decorator. It either passes a user to the page or sends them to a 401 restricted page, as a cherrypy.Tool , like this: from user

Can't call a decorator within the imported sub-class of a cherrpy application (site tree)

只谈情不闲聊 提交于 2020-01-24 00:27:07
问题 I am using cherrypy as a web server, and I want to check a user's logged-in status before returning the page. This works on methods in the main Application class (in site.py ) but gives an error when I call the same decorated function on method in a class that is one layer deeper in the webpage tree (in a separate file). validate_user() is the function used as a decorator. It either passes a user to the page or sends them to a 401 restricted page, as a cherrypy.Tool , like this: from user

Derived class explicit base constructor call

强颜欢笑 提交于 2020-01-23 18:21:15
问题 I am trying to learn C#. The below data is from a Microsoft C# help website. I don't understand this statement, "If a base class does not offer a default constructor, the derived class must make an explicit call to a base constructor by using base." I thought that if there is no default constructor for a class, C# will automatically assign default values to int, char or whatever is declared in a class. If a base class does not have a constructor and it has a child class, does the rule

Derived class explicit base constructor call

心已入冬 提交于 2020-01-23 18:21:06
问题 I am trying to learn C#. The below data is from a Microsoft C# help website. I don't understand this statement, "If a base class does not offer a default constructor, the derived class must make an explicit call to a base constructor by using base." I thought that if there is no default constructor for a class, C# will automatically assign default values to int, char or whatever is declared in a class. If a base class does not have a constructor and it has a child class, does the rule

How to retrieve a class name?

本小妞迷上赌 提交于 2020-01-23 16:41:04
问题 I am using Ruby on Rails 3.0.7 and I would like to retrieve the class name, also if it is namespaced. For example, if I have a class named User::Profile::Manager I would retrieve the Manager string from that using some unknown to me Ruby or Ruby on Rails method and in a secure way. BTW : What other "usefull" information that are "commonly" used can I get for the class? 回答1: Some useful simple metaprogramming calls: user = User::Profile::Manager.new(some_params) user.class # => User::Profile:

Sealed密封类

浪子不回头ぞ 提交于 2020-01-23 14:11:49
当对一个类应用 sealed 修饰符时,此修饰符会阻止其他类从该类继承。 在下面的示例中,类 B 从类 A 继承,但是任何类都不能从类 B 继承。 class A {} sealed class B : A {} 还可以在重写基类中的虚方法或虚属性的方法或属性上使用 sealed 修饰符。 这将使您能够允许类从您的类继承,并防止它们重写特定的虚方法或虚属性。 在下面的示例中, Z 从 Y 继承,但 Z 无法重写在 X 中声明并在 Y 中密封的虚函数 F 。 View Code 1 class X 2 { 3 protected virtual void F() { Console.WriteLine("X.F"); } 4 protected virtual void F2() { Console.WriteLine("X.F2"); } 5 } 6 class Y : X 7 { 8 sealed protected override void F() { Console.WriteLine("Y.F"); } 9 protected override void F2() { Console.WriteLine("X.F3"); }10 }11 class Z : Y12 {13 // Attempting to override F causes compiler error

Simple XML framework on android, class attribute

感情迁移 提交于 2020-01-23 10:47:08
问题 Ive got a weird problem with simplexml framework on android. Im trying to read and fill an object called weatherdata from a xml source. XML File (no control on this one): <weatherdata> <product class="pointData"> .... </product> </weatherdata> So my java file looks like : @Root(name = "weatherdata", strict=false) public class Weatherdata { @Element(name="product", required = true) protected ProductType product; But I get a very weird error : 01-14 14:22:28.919: W/System.err(18011): java.lang

Simple XML framework on android, class attribute

让人想犯罪 __ 提交于 2020-01-23 10:46:12
问题 Ive got a weird problem with simplexml framework on android. Im trying to read and fill an object called weatherdata from a xml source. XML File (no control on this one): <weatherdata> <product class="pointData"> .... </product> </weatherdata> So my java file looks like : @Root(name = "weatherdata", strict=false) public class Weatherdata { @Element(name="product", required = true) protected ProductType product; But I get a very weird error : 01-14 14:22:28.919: W/System.err(18011): java.lang

Global PHP class in functions?

给你一囗甜甜゛ 提交于 2020-01-23 08:38:06
问题 Is there a way to access one instance of a class inside functions in PHP? Like this: include("class.php"); $bla=new Classname(); function aaa(){ $bla->DoSomething(); //Doesn't work. } $bla->DoSomething(); //Works. 回答1: If I interpret your question correctly, then the proper way to do this is create a singleton class. class Singleton { private static $instance; private function __construct() {} private function __clone() {} public static function getInstance() { if (!Singleton::$instance