<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.in28minutes</groupId>
	<artifactId>in28Minutes-first-webapp</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<packaging>war</packaging>

	<dependencies>
		<dependency>
			<groupId>javax</groupId>
			<artifactId>javaee-web-api</artifactId>
			<version>6.0</version>
			<scope>provided</scope>
		</dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>jstl</artifactId>
            <version>1.2</version>
        </dependency>
		
	</dependencies>

	<build>
		<pluginManagement>
			<plugins>
				<plugin>
					<groupId>org.apache.maven.plugins</groupId>
					<artifactId>maven-compiler-plugin</artifactId>
					<version>3.2</version>
					<configuration>
						<verbose>true</verbose>
						<source>1.7</source>
						<target>1.7</target>
						<showWarnings>true</showWarnings>
					</configuration>
				</plugin>
				<plugin>
					<groupId>org.apache.tomcat.maven</groupId>
					<artifactId>tomcat7-maven-plugin</artifactId>
					<version>2.2</version>
					<configuration>
						<path>/</path>
						<contextReloadable>true</contextReloadable>
					</configuration>
				</plugin>
			</plugins>
		</pluginManagement>
	</build>
</project>

package in28minutes.login;

public class LoginService {
	public boolean validateUser(String user, String password) {
		return user.equalsIgnoreCase("in28Minutes") && password.equals("dummy");
	}

}

package in28minutes.login;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


@WebServlet(urlPatterns = "/login.do")
public class LoginServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;
	private LoginService service = new LoginService();

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws IOException, ServletException {
		request.getRequestDispatcher("/WEB-INF/views/login.jsp").forward(request, response);
	}

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws IOException, ServletException {
		String name = request.getParameter("name");
		String password = request.getParameter("password");

		boolean isValidUser = service.validateUser(name, password);

		if (isValidUser) {
			response.sendRedirect("/todo.do");
		} else {
			request.setAttribute("errorMessage", "Invalid Credentials!!");
			request.getRequestDispatcher("/WEB-INF/views/login.jsp").forward(request, response);
		}
	}

}

package in28minutes.todo;

public class Todo {

	public Todo(String name) {
		super();
		this.name = name;
	}

	private String name;

	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}

	@Override
	public String toString() {
		return "Todo [name=" + name + "]";
	}
}

package in28minutes.todo;

import java.util.ArrayList;
import java.util.List;

public class TodoService {
	private static List<Todo> todos = new ArrayList<Todo>();

	static {
		todos.add(new Todo("Learn Web Application"));
		todos.add(new Todo("Learn Spring"));
		todos.add(new Todo("Learn Spring MVC"));
	}

	public List<Todo> retrieveTodos() {
		return todos;
	}

	public void addTodo(String todo) {
		todos.add(new Todo(todo));
	}
}

package in28minutes.todo;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(urlPatterns = "/todo.do")
public class TodoServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;
	private TodoService todoService = new TodoService();

	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws IOException, ServletException {
		request.setAttribute("todos", todoService.retrieveTodos());
		request.getRequestDispatcher("/WEB-INF/views/todo.jsp").forward(request, response);
	}

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws IOException, ServletException {
		String todo = request.getParameter("todo");
		if ("".equals(todo)) {
			request.setAttribute("errorMessage", "Enter a valid todo");
		} else {
			todoService.addTodo(todo);
		}
		request.setAttribute("todos", todoService.retrieveTodos());
		request.getRequestDispatcher("/WEB-INF/views/todo.jsp").forward(request, response);
	}

}

<html>
<head>
<title>Yahoo!!</title>
</head>
<body>
	<p><font color="red">${errorMessage}</font></p>
	<form action="/login.do" method="POST">
		Name : <input name="name" type="text" /> Password : <input name="password" type="password" /> <input type="submit" />
	</form>
</body>
</html>

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<html>
<head>
<title>Yahoo!!</title>
</head>
<body>
<H1>Welcome ${name}</H2>
<div>
Your Todos are
<ol>
<c:forEach items="${todos}" var="todo">
   <li>${todo.name}</li>
</c:forEach>
</ol>

<p><font color="red">${errorMessage}</font></p>
<form method="POST" action="/todo.do">
New Todo : <input name="todo" type="text" /> <input name="add" type="submit" />
</form>

</div>
</body>
</html>

<!-- webapp/WEB-INF/web.xml -->
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
	version="3.0">

	<display-name>To do List</display-name>

	<welcome-file-list>
		<welcome-file>login.do</welcome-file>
	</welcome-file-list>
</web-app>