Java MVC (Model View Controller) ---- (JSP + servlet + javabean instance)

I finally came into contact with MVC in DRP. I feel that such an architecture system is indeed quite flexible. Now I feel that tomcat is used as a server for publishing much better than IIS. At least it is very simple and easy to use.

First, let's take a simple look at the basic knowledge of MVC. The full name of MVC is Model View Controller, short for model-view-controller, A software design model that organizes Code by means of explicit separation of business logic and data, and aggregates business logic into a component, the interface and user interaction around data can be improved and customized without re-writing the business logic.

Overview

MVC is uniquely developed to map traditional input, processing, and output functions in a logical graphical user interface structure. MVC is the embodiment of hierarchical thinking, but it is different from the three-tier design model (we will share the difference with you later ).

MVC is a framework model that forcibly separates the input, processing, and output of an application. MVC applications are divided into three core components: model, view, and controller. They process their own tasks. The most typical MVC is the JSP + servlet + javabean mode.

Instance resolution

UML diagram: familiar with MVC call process logic

First: JSP: the query interface query_condention.jsp, which consists of page commands and HTML, is similar to the current html page and asp page.

<% @ Page language = "java" contentType = "text/html; charset = GBK" %>Student Information

Second: the control layer SearchStudentServlet is used to accept the customer's request to process the process. It calls Model (StudentManager. java) and forwards it to the student_list.jsp page of the backend server to be requested.

Import java. text. *; import java. util. *; import java. io. *; import javax. servlet. http. *; import javax. servlet. *; import com. bjpowernode. exam. model. *; import com. bjpowernode. exam. manager. *; public class SearchStudentServlet extends HttpServlet {public void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {doPost (request, response);} public void doPost (HttpServletRequest, httpServletResponse response) throws ServletException, IOException {String sBeginDate = request. getParameter ("beginDate"); String sEndDate = request. getParameter ("endDate"); Date beginDate = new Date (); Date endDate = new Date (); try {beginDate = new SimpleDateFormat ("yyyy-MM-dd "). parse (sBeginDate); endDate = new SimpleDateFormat ("yyyy-MM-dd "). parse (sEndDate);} catch (Exception e) {e. printStackTrace ();} StudentManager studentManager = new StudentManagerImpl (); List
 
  
StudentList = studentManager. findStudentList (beginDate, endDate); // sets the student list to the requet range // request. setAttribute ("student_list", studentList); // forward, which is forwarded on the server and unknown on the client. // request. getRequestDispatcher ("/student_list.jsp "). forward (request, response); // put studentList in session HttpSession session = request. getSession (); session. setAttribute ("student_list", studentList); // redirection, does not share the request // The following syntax error. This "/" indicates port 8080 // response. sendRedirect ("/student_list.jsp"); response. sendRedirect (request. getContextPath () + "/student_list.jsp ");}}
 

Third: The student_list.jsp page receives data to form html, returns to the browser, and renders the data on the interface.

<% @ Page language = "java" contentType = "text/html; charset = GBK" %> <% @ page import = "java. util. * "%> <% @ page import =" java. text. * "%> <% @ page import =" com. bjpowernode. exam. model. * "%> <% @ page import =" com. bjpowernode. exam. manager. * "%>Student Information
 
  
StudentList = (List) request. getAttribute ("student_list"); List
  
   
StudentList = (List) session. getAttribute ("student_list"); for (Iterator
   
    
Iter = studentList. iterator (); iter. hasNext ();) {Student student = iter. next (); %>
   
  
 
 
 <% // List 
   <% Long B = 1000L * 60L * 60L * 24L * 365L; long a = System. currentTimeMillis ()-student. getBirthday (). getTime (); %> 
    <% }%> 
  

  
  
 
   
 
    
Student code
 
    
Name
 
    
Gender
 
    
Date of birth
 
    
Contact number
 
    
Home address
 
    
Class Name
 
    
Age
 
   
 
    
<% = Student. getStudentId () %>
 
    
<% = Student. getStudentName () %>
 
    
<% = Student. getSex () %>
 
    
<% = New SimpleDateFormat ("yyyy-MM-dd"). format (student. getBirthday () %>
 
    
<% = Student. getContactTel () %>
 
    
<% = Student. getAddress () %>
 
    
<% = Student. getClasses (). getClassesName () %>
<% = A/B %>
 
   
 
 

In View's student_list.jsp page, there is a large mix of html and java code. In the query condition interface, query_condention.jsp is mainly html, because it does not involve background data interaction.

Fourth: xml configuration Servlet:

 
 
  
   
    SearchStudentServlet
   
   
    SearchStudentServlet
   
  
  
   
    SearchStudentServlet
   
   
    /SearchStudentServlet
   
  
 

Fifth: display query results

Java is a type of blog that can be learned and improved together. Stay tuned!