How it is possible to create object for HttpServletRequest Interface?
如何为HttpServletRequest接口创建对象？
HttpServletRequest is an interface, but still servlet container can create object of the same. How? Why?
HttpServletRequest是一个接口，但仍然是servlet容器可以创建相同的对象。怎么样？为什么？
1 个解决方案
#1
5
The servlet container has a class implementing this interface, and instantiates an object of this class. Just like when you do
servlet容器有一个实现此接口的类，并实例化该类的对象。就像你做的那样
List<String> list = new ArrayList<String>();
List is an interface, and you instantiate ArrayList, which is a class implementing List.
List是一个接口，您实例化ArrayList，它是一个实现List的类。
The servlet container does something like the following:
servlet容器执行以下操作：
HttpServletRequest request = new TomcatHttpServletRequestImpl();
This is the basis of OO and polymorphism.
这是OO和多态性的基础。
#1
5
The servlet container has a class implementing this interface, and instantiates an object of this class. Just like when you do
servlet容器有一个实现此接口的类，并实例化该类的对象。就像你做的那样
List<String> list = new ArrayList<String>();
List is an interface, and you instantiate ArrayList, which is a class implementing List.
List是一个接口，您实例化ArrayList，它是一个实现List的类。
The servlet container does something like the following:
servlet容器执行以下操作：
HttpServletRequest request = new TomcatHttpServletRequestImpl();
This is the basis of OO and polymorphism.
这是OO和多态性的基础。