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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