Spring Framework

Overview to MVC

MVC or Model View Controller is a controller is a design pattern . This design pattern involves a Model(manages data and logic ), a view (interacting with user) and a controller(which is in between the model and view and controls the commands between model and view).Spring MVC is a module in spring framework as we discussed earlier.This chapter gives a very simple Spring MVC Tutorial . We are discussing a simple Spring MVC example

Concept of dispatcher servlet in Spring MVC

It is the central sevlet in Spring MVC which dispatches the requests from view to controller and vice versa. It does even more than that.It is integrated with Spring IoC container so that we can use every other feature that spring has.

Tools Used:

1)Eclipse
2)Apache Tomcat 8.0

Steps

1)Open Eclipse in suitable work space and create a new maven project
1

2)Select web app archetype while creating the project3_webapp_archtype
3)Give group id , artifact id version and package properly and press Finish

4

4)Create a new server instance and add the project to it

5_addserver

5)Right click on the project and select the configure build path option , if the project is having errors after creation

6

6)Select Add Library option

7_addlibrray

7)Add server run time libraries. We are using Apache Tomcat

8

8)Edit the pom.xml

	4.0.0
	com.samples
	SpringSample
	war
	0.0.1-SNAPSHOT
	SpringSample Maven Webapp
	http://maven.apache.org
	
		4.1.0.RELEASE
	
	
		
			junit
			junit
			3.8.1
			test
		
		
			org.springframework
			spring-core
			${org.springframework-version}
		
		
			org.springframework
			spring-context
			${org.springframework-version}
		
		
			org.springframework
			spring-webmvc
			${org.springframework-version}
		
		
			org.springframework
			spring-beans
			${org.springframework-version}
		
		
			org.springframework
			spring-expression
			${org.springframework-version}
		
		
			javax.servlet
			jstl
			1.2
			
	
	
		SpringSample
	

9)We are developing a login form with an annotated controller. The index.jsp is the welcome file. From the index page , it is redirecting to the /login of the controller and from there to loginpage.jsp.JSTL is using to do the redirect from index.jsp . The jsp page loginpage.jsp has the login form. When user submits the form ,the /login with POST method is invoking and the successpage.jsp will be rendered.

web.xml

	Archetype Created Web Application
	
		dispatcher
		
			org.springframework.web.servlet.DispatcherServlet
		
		
		1
		
	
	
		dispatcher
		/
	
	
 
 contextConfigLocation
 /WEB-INF/dispatcher-servlet.xml
 
 
 
 
 
 org.springframework.web.context.ContextLoaderListener
 

index.jsp

dispatcher-servlet.xml

 
	
 
	
		
			/WEB-INF/pages/
		
		
			.jsp
		
	

The servlet file defines the package where the container needs to look for dependencies . Also it provides the viewResolver bean which injects the view pages.

index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> 

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;
import com.sample.models.User;
@Controller
@RequestMapping("/")
public class LoginController {
	
	@RequestMapping(value = "login", method = RequestMethod.GET)
	public ModelAndView login(Model model) {
		System.out.println("Re directing to login page");
		model.addAttribute("user", new User()); 
		return new ModelAndView("loginpage");
	}
	@RequestMapping(value = "login", method = RequestMethod.POST)
	public ModelAndView doLogin(@ModelAttribute("user") User user,BindingResult result) {
		System.out.println("Received User Details : "+user);
		return new ModelAndView("successpage");
	}
}

public class User {
	private String userId;
	private String password;
	public String getUserId() {
		return userId;
	}
	public void setUserId(String userId) {
		this.userId = userId;
	}
	public String getPassword() {
		return password;
	}
	public void setPassword(String password) {
		this.password = password;
	}
	public String toString() {
		return "User Id = " + userId + " ; Password = " + password;
	}
}

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>

<%@taglib uri="http://www.springframework.org/tags/form" prefix="form"%>






	

		
			
				 Login Id
				 
				
			
			
				 Password
				 
				
			
			
				 
			
		
	

<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%>







Welcome