MVC (Model.view,controller)

(i) MVC

JavaBean: Java components that conform to a specification, that is, Java classes

Model models that manipulate data in the business processing layer and are independent of the presentation layer.

The view view, which displays data through the client data type and echoes the execution results of the model layer.

Conroller Controller. A bridge between the view layer and the model layer that controls the flow of data, accepts events emitted by the view layer, and redraws the view.

"Personal understanding: In the MVC design model is the model layer, for the management of data, operation of data, view is the views layer, is the effect of the page display, Conroller is the control layer, used to control how to do the operation, such as adding and removing changes, and then after successful execution, in the View display page, The most common MVC pattern is the Jsp,servlet, and JavaBean "

An implementation type of the MVC framework.

Jsp+servlet+javabean, with control as the core, JSP is only responsible for displaying and collecting data, servlets, connection views and models,

The view layer data, sent to the model layer, JavaBean, divided into business classes and data entities, business class processing business data, data entities, hosting data, basically most of the projects are using this MVC implementation pattern.

Combine struts to illustrate its use in the Web.

(ii) WebService

WebService is a (SOA) service-oriented programming architecture that is not dependent on the language, does not depend on the platform, and can

Implement mutual invocation of different language pieces. It is an SOA architecture that enables different programs to integrate by providing standard protocols and interfaces.

(iii) Middleware

Middleware is a variety of components that can be implanted in a program, reusable, and unrelated to the business logic.

(iv) Talk about the difference between HashMap and Hashtable

are classes of map interfaces that implement the mapping of unique keys to specific values.

HashMap is lightweight, thread unsafe, high-efficiency collection, unsynchronized, allowed to have null

Hashtable is a collection of heavyweight, thread-safe, and efficient. Synchronous, no NULL allowed

No sorting and sorting.

(v) Please ask the abstract class and interface

1, the pretext does not have any realization, but the abstract class it can have partial realization also can not;

2, if you need to reuse or share part of the code, you should use an abstract class instead of an interface.

3, inheritance does not resolve the type of conversion problem, the interface is to solve this problem (the Java single inheritance is the root cause of the interface) interface is an abstract third-party specification, with the object is not directly related.

(vi) What are the design patterns in development?

Singleton mode, DAO mode, Factory mode, MVC mode

(vii) The core characteristics of the class, inheriting the polymorphic encapsulation.

(eight) What is the difference between a class and an object?

Class: A general set of things that is the same or similar abstraction of the common characteristics of each food.

Object: In object-oriented concepts, an object is an instance of a class, and the relationship between an object and a class is just like the relationship of a variable to a data type.

MVC (Model.view,controller)