27. Spring MVC Complete Example [******* Important**********]

In this Example
1.       Model à Simple Beans
2.       Controllers
·         FrontController à DispatcherServlet
·         User Controller à Controller (Interface)

3.       View
·         JSP’s,
·         InternalresourceViewResolver class

4.       Xml’s
·         Web.xml à to configure FrontController
·         Spring.xml à Configure the Usercontroller (controller-servlet.xml)

Controller Interface
·         It is the Basic Controller
·         It contains public ModelandView handleRequest(req,res)
·         While returing ModelandView(“page” Map) we must place all the data to Map object

InternalresourceViewResolver Class
·         Used for  result page mappings
·         It has two properties, we have to configure these in spring.xml
·         Prefix à for Folder / Directory where pages are placed
·         Suffix à extension of result pages (.jsp, .html etc)
ModelandView Class
·         It contains the model data like id,name,bean data
·         View data like success, error, other pages
·         It has parameter constructor ModelandView(“page” Map)
·         Page contains result page name
·         Map contains all bean data return to resultpage
HandlerMapping class
·         It is a mediator between FrontController and User specific Controller
·         After getting request Dispacherservlet asks HandlerMapping , which Specific Controller to be called
·          HandlerMapping gives the Specific Controller to FrontController

Exmaple Code

Input.jsp
<form action="./hello.ds">
Name : <input type="text" name="name"><br>
<button type="submit">Submit</button>
</form>

Success.jsp
<h1>SUCCESS</h1>
${msg}

HelloServlet.java
package controller;

import java.util.HashMap;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;

public class HelloServlet implements Controller{
      
       @Override
       public ModelAndView handleRequest(HttpServletRequest req,
                     HttpServletResponse res) throws Exception {
              // TODO Auto-generated method stub
             
              String msg = req.getParameter("name");
              Map map = new HashMap();
              map.put("msg", msg);
             
              return new ModelAndView("success",map);
       }

}


Web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>MVC_1helloworld</display-name>
  <welcome-file-list>
 
    <welcome-file>input.jsp</welcome-file>
  
  </welcome-file-list>
 
  <servlet>
  <servlet-name>hello</servlet-name>
 <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> 
   </servlet>
 
  <servlet-mapping>
  <servlet-name>hello</servlet-name>
  <url-pattern>*.ds</url-pattern>
  </servlet-mapping>
</web-app>

hello-servlet.xml
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN"
                "http://www.springframework.org/dtd/spring-beans-2.0.dtd">
<beans>
<!-- 1. Handler Class Conguration -->
<bean class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping"></bean>

<!-- 1. Controller Class Conguration -->
<bean name="/hello.ds" class="controller.HelloServlet"></bean>

<!-- 1. ViewandResolve Class Conguration -->
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/" ></property>
<property name="suffix" value=".jsp"></property>
</bean>


</beans>
===============================================
EXCEPTION RESOLVING NOTES
==================================

in web.xml
                 / ==> means for all URLs
              *.ds ==> means URL's with .ds extension
            /hello ==> mean URL with hello as action

in hello-servlet.xml
          <bean name="/hello" class="controller.HelloServlet"></bean>
          name="/hello" ==> must be same as ACTION Name in <form action="hello">

xml name should be actionname-servlet.xml


==> all XML's web.xml and hello-servlet.xml must be Under WEB-INF/ Folder


------------------------XSD---------------------------

<beans xmlns="http://www.springframework.org/schema/beans"
   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
   xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mvc="http://www.springframework.org/schema/mvc"
   xsi:schemaLocation="http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans.xsd
   http://www.springframework.org/schema/context
   http://www.springframework.org/schema/context/spring-context.xsd
   http://www.springframework.org/schema/mvc
 http://www.springframework.org/schema/mvc/spring-mvc.xsd">

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